@article {NORIEGA2025101425,
	title = {Approaches to quantify and manipulate insect hormone signals},
	journal = {Current Opinion in Insect Science},
	volume = {72},
	year = {2025},
	pages = {101425},
	abstract = {Hormones play a decisive role in many aspects of ins...ds from insect samples and to manipulate endocrine homeostasis.},
	issn = {2214-5745},
	doi = {10.1016/j.cois.2025.101425},
	url = {https://www.sciencedirect.com/science/article/pii/S2214574525000951},
	author = {Noriega, Fernando G. and Bloch, Guy and Moos, Martin and Simek, Petr and Jindra, Marek}
}
@article {27546,
	title = {Diversification of social complexity following a major evolutionary transition in bees},
	journal = {Current Biology},
	year = {2025},
	month = {2025},
	abstract = {How social complexity evolved remains a long-standing enigma. In most animal groups, social complexity is typically classified into a few discrete classes. This approach is oversimplified and constrains our inference of social evolution to a narrow trajectory consisting of transitions between classes. Such categorical classifications also limit quantitative studies on the molecular and environmental drivers of social complexity. The recent accumulation of relevant quantitative data has set the stage to overcome these limitations. Here, we propose a data-driven, high-dimensional approach for studying the full diversity of social phenotypes. We curated and analyzed a comprehensive dataset encompassing 17 social traits across 80 species and studied the evolution of social complexity in bees. We found that honey bees, stingless bees, and bumble bees underwent a major evolutionary transition \~80 mya, inconsistent with the stepwise progression of the social ladder conceptual framework. This major evolutionary transition was followed by a phase of substantial phenotypic diversification of social complexity. Other bee lineages display a continuum of social complexity, ranging from solitary to simple societies, but do not reach the levels of social complexity seen in honey bees, stingless bees, and bumble bees. Bee evolution, therefore, provides a remarkable demonstration of a macroevolutionary process in which a major transition removed biological constraints and opened novel evolutionary opportunities, driving the exploration of the landscape of social phenotypes. Our approach can be extended to incorporate additional data types and readily applied to illuminate the evolution of social complexity in other animal groups.},
	url = {https://www.sciencedirect.com/science/article/pii/S0960982225000090?dgcid=author},
	author = {Ohad Peled and Gili Greenbaum and Bloch, Guy}
}
@article {SHALEM2025101433,
	title = {Juvenile hormone signaling and social complexity in the Hymenoptera},
	journal = {Current Opinion in Insect Science},
	volume = {72},
	year = {2025},
	pages = {101433},
	abstract = {The seminal discovery that in adults of the highly social honey bee (Apis mellifera), juvenile hormone (JH) regulates age-related division of labor (DoL) but not adult fertility, unlike in most insects, has led to the hypothesis that the evolution of insect sociality involved modifications in JH signaling. Recent studies examining JH functions across the Hymenoptera provide two main insights: First, significant progress in studies of the bumble bee Bombus terrestris, which exhibits an intermediate level of social complexity relative to honey bees, shows that JH regulates multiple tissues involved in reproduction, but not task performance. JH also seems to function as a primary gonadotropin in bees showing solitary lifestyles or low levels of social complexity, highlighting a marked contrast with its roles in honey bees. Second, this association between JH function and social complexity in bees does not generalize to other lineages. The few studies on JH function in highly social stingless bees are not consistent with the honey bee model. In wasps and hornets, JH typically influences both fertility and age-related DoL. There is substantial variability across ant species, offering no consistent model linking JH function to social complexity. We propose that although JH signaling is commonly modified in social insects, the specific changes differ between {\textemdash} and sometimes within {\textemdash} lineages. There is no one model linking JH function to social complexity across major lineages, likely due to changes in related pathways. These modifications enable social insects to circumvent the trade-off between reproduction and maintenance.},
	issn = {2214-5745},
	doi = {https://doi.org/10.1016/j.cois.2025.101433},
	url = {https://www.sciencedirect.com/science/article/pii/S2214574525001038},
	author = {Yuval Shalem and Tzvi S Goldberg and Guy Bloch}
}
@article {GOLDBERG2025104902,
	title = {Precocene-I mediated reduction of juvenile hormone titers and ovarian activity is ephemeral in a bumble bee},
	journal = {Journal of Insect Physiology},
	volume = {167},
	year = {2025},
	pages = {104902},
	abstract = {Juvenile hormones (JHs) are key insect endocrine sig... compare methods for reducing circulating JH levels in insects.},
	keywords = {Bumble bee, Corpora allata, Juvenile hormone, Juvenile hormone analog, Reproduction},
	issn = {0022-1910},
	doi = {10.1016/j.jinsphys.2025.104902},
	url = {https://www.sciencedirect.com/science/article/pii/S0022191025001568},
	author = {Goldberg, Tzvi S. and Shalem, Yuval and Fujinaga, Daiki and Mauck, Kerry E. and Woodard, S. Hollis and Yamanaka, Naoki and Bloch, Guy}
}
@article {3214588,
	title = {The alkenes Z9-C29 and Z9-C31 function as quorum-sensing pheromones stimulating worker reproduction in the bumble bee <em>Bombus terrestris</em>},
	journal = {Nature Communications},
	volume = {16},
	year = {2025},
	month = {2025/11/28},
	pages = {10770},
	abstract = {Division of labor in reproduction in eusocial insects is governed by delicate and context- dependent mechanisms, yet the regulatory processes remain largely unclear. Here, we investigate social cues involved in the establishment of reproductive dominance in bumble bee (Bombus terrestris) workers. We reveal the roles of two alkenes, (Z)-9-nonacosene (Z9- C29) and (Z)-9-hentriacontene (Z9- C31) in the activation of ovarian development. These alkenes are found throughout the queenright bumble bee colony, including wax, workers, drones, and gynes, and their levels are positively correlated with colony size. They act as quorum-sensing pheromones that facilitate ovary maturation in a threshold-dependent manner under queenright conditions. A synergistic interaction between the perception of these two alkenes and the occurrence of dominance contests is essential for the ovary development of worker bumble bees, independent of temporal sequence. Artificial addition of these two alkenes into colonies confirms their stimulatory effects on the ovarian developmental potential of worker bees, even in the presence of a queen. Our findings highlight a quorum-sensing-like mechanism that primes the initiation of worker ovary development, providing insights into the complex regulation of context-dependent reproductive plasticity in social insects.},
	isbn = {2041-1723},
	url = {https://doi.org/10.1038/s41467-025-65812-x},
	author = {Ge, Zhuxi and Ge, Jin and Zhu, Dan and Nie, Xin and Millar, Jocelyn G. and Bloch, Guy and Wang, Xianhui}
}
@article {SCHEINER2024101257,
	title = {Editorial overview: How do social insects know their tasks?},
	journal = {Current Opinion in Insect Science},
	volume = {66},
	year = {2024},
	pages = {101257},
	issn = {2214-5745},
	doi = {https://doi.org/10.1016/j.cois.2024.101257},
	url = {https://www.sciencedirect.com/science/article/pii/S2214574524000993},
	author = {Ricarda Scheiner and Bloch, Guy}
}
@article {doi:10.1177/07487304241283863,
	title = {Sex-Related Variation in Circadian Rhythms in the Bumble Bee Bombus terrestris},
	journal = {Journal of Biological Rhythms},
	volume = {39},
	number = {6},
	year = {2024},
	note = {PMID: 39370745},
	pages = {594{\textendash}606},
	abstract = {Mating success depends on many factors, but first of all, a male and a female need to meet at the same place and time. The circadian clock is an endogenous system regulating activity and sex-related behaviors in animals. We studied bumble bees (Bombus terrestris) in which the influence of circadian rhythms on sexual behavior has been little explored. We characterized circadian rhythms in adult emergence and locomotor activity under different illumination regimes for males and gynes (unmated queens). We developed a method to monitor adult emergence from the pupal cocoon and found no circadian rhythms in this behavior for either males or gynes. These results are not consistent with the hypothesis that the circadian clock regulates emergence from the pupa in this species. Consistent with this premise, we found that both gynes and males do not show circadian rhythms in locomotor activity during the first 3 days after pupal emergence, but shortly after developed robust circadian rhythms that are readily shifted by a phase delay in illumination regime. We conclude that the bumble bees do not need strong rhythms in adult emergence and during early adult life in their protected and regulated nest environment, but do need strong activity rhythms for timing flights and mating-related behaviors. Next, we tested the hypothesis that the locomotor activity of males and gynes have a similar phase, which may improve mating success. We found that both males and gynes have strong endogenous circadian rhythms that are entrained by the illumination regime, but males show rhythms at an earlier age, their rhythms are stronger, and their phase is slightly advanced relative to that of gynes. An earlier phase may be advantageous to males competing to mate a receptive gyne. Our results are consistent with the hypothesis that sex-related variations in circadian rhythms is shaped by sexual selection.},
	doi = {10.1177/07487304241283863},
	url = {https://doi.org/10.1177/07487304241283863},
	author = {Gonulkirmaz-Cancalar, Ozlem and Bloch, Guy}
}
@article {insects14080707,
	title = {Bumble Bees (Bombus terrestris) Use Time-Memory to Associate Reward with Color and Time of Day},
	journal = {Insects},
	volume = {14},
	number = {8},
	year = {2023},
	abstract = {Circadian clocks regulate ecologically important complex behaviors in honey bees, but it is not clear whether similar capacities exist in other species of bees. One key behavior influenced by circadian clocks is time-memory, which enables foraging bees to precisely time flower visitation to periods of maximal pollen or nectar availability and reduces the costs of visiting a non-rewarding flower patch. Bumble bees live in smaller societies and typically forage over shorter distances than honey bees, and it is therefore not clear whether they can similarly associate reward with time of day. We trained individually marked bumble bee (Bombus terrestris) workers to forage for sugar syrup in a flight cage with yellow or blue feeders rewarding either during the morning or evening. After training for over two weeks, we recorded all visitations to colored feeders filled with only water. We performed two experiments, each with a different colony. We found that bees tended to show higher foraging activity during the morning and evening training sessions compared to other times during the day. During the test day, the trained bees were more likely to visit the rewarding rather than the non-rewarding colored feeders at the same time of day during the test sessions, indicating that they associated time of day and color with the sugar syrup reward. These observations lend credence to the hypothesis that bumble bees have efficient time-memory, indicating that this complex behavior is not limited to honey bees that evolved sophisticated social foraging behaviors over large distances.},
	issn = {2075-4450},
	doi = {10.3390/insects14080707},
	url = {https://www.mdpi.com/2075-4450/14/8/707},
	author = {Gonulkirmaz-Cancalar, Ozlem and Shertzer, Oded and Bloch, Guy}
}
@article {GOLDBERG2023101107,
	title = {Inhibitory signaling in collective social insect networks, is it indeed uncommon?},
	journal = {Current Opinion in Insect Science},
	year = {2023},
	pages = {101107},
	abstract = {Individual entities across levels of biological organization interact to reach collective decisions. In centralized neuronal networks, competing neural populations commonly accumulate information over time while increasing their own activity, and cross-inhibiting other populations until one group passes a given threshold. In social insects, there is good evidence for decisions mediated by positive feedbacks, but we found evidence for similar inhibitory signals only in honey bee (Apis mellifera) stop signals, and Pharaoh{\textquoteright}s ant (Monomorium pharaonic) repellent pheromones, with only the former occasionally being used as cross-inhibition. We discuss whether these differences stem from insufficient research effort or represent genuine differences across levels of biological organization.},
	issn = {2214-5745},
	doi = {https://doi.org/10.1016/j.cois.2023.101107},
	url = {https://www.sciencedirect.com/science/article/pii/S2214574523001049},
	author = {Tzvi S. Goldberg and Bloch, Guy}
}
@article {GE2023101115,
	title = {Integration of information from multiple sources drives and maintains the division of labour in bumble bee colonies},
	journal = {Current Opinion in Insect Science},
	year = {2023},
	pages = {101115},
	abstract = {Bumble bees are eusocial bees in which the division of labor in reproduction and in task performance changes during their annual life cycle. The queen monopolizes reproduction in young colonies, but at later stages some workers start to challenge the queen and lay their own unfertilized eggs. The division of colony maintenance and growth tasks relates to worker body size. Reproduction and task performance are regulated by multiple social signals of the queen, the workers, and the brood. Here we review recent studies suggesting that bumble bees use multiple sources of information to establish and maintain division of labor in both reproduction and in task performance. Juvenile hormone is an important neuroendocrine signal involved in the regulation of division of labor in reproduction but not in worker task performance. The reliance on multiple signals facilitate flexibility in face of changes in the social and geophysical environment. Data Availability No data were used for the research described in the article.},
	issn = {2214-5745},
	doi = {https://doi.org/10.1016/j.cois.2023.101115},
	url = {https://www.sciencedirect.com/science/article/pii/S2214574523001128},
	author = {Jin Ge and Yuval Madmon-Butbul Shalem and Zhuxi Ge and Jinpeng Liu and Xianhui Wang and Bloch, Guy}
}
@article { doi:10.1073/pnas.2302071120,
	title = {Substances in the mandibular glands mediate queen effects on larval development and colony organization in an annual bumble bee},
	journal = {Proceedings of the National Academy of Sciences},
	volume = {120},
	number = {45},
	year = {2023},
	pages = {e2302071120},
	abstract = {Social organization is commonly dynamic, with extreme examples in annual social insects, but little is known about the underlying signals and mechanisms. Bumble bee larvae with close contact to a queen do not differentiate into gynes, pupate at an earlier age, and are commonly smaller than siblings that do not contact a queen. We combined detailed observations, proteomics, microRNA transcriptomics, and gland removal surgery to study the regulation of brood development and division of labor in the annual social bumble bee Bombus terrestris. We found that regurgitates fed to larvae by queens and workers differ in their protein and microRNA composition. The proteome of the regurgitate overlaps significantly with that of the mandibular (MG) and hypopharyngeal glands (HPG), suggesting that these exocrine glands are sources of regurgitate proteins. The proteome of the MG and HPG, but not the salivary glands, differs between queens and workers, with caste-specificity preserved for the MG and regurgitate proteomes. Queens subjected to surgical removal of the MG showed normal behavior, brood care, and weight gain, but failed to shorten larval development. These findings suggest that substances in the queen MG are fed to larvae and influence their developmental program. We suggest that when workers emerge and contribute to larval feeding, they dilute the effects of the queen substances, until she can no longer manipulate the development of all larvae. Longer developmental duration may allow female larvae to differentiate into gynes rather than to workers, mediating the colony transition from the ergonomic to the reproductive phase.},
	doi = {10.1073/pnas.2302071120},
	url = {https://www.pnas.org/doi/abs/10.1073/pnas.2302071120},
	author = {Maayan Franco and Fassler, Rosi and Tzvi S. Goldberg and Hanna Chole and Yogev Herz and Woodard, S. Hollis and Reichmann, Dana and Bloch, Guy}
}
@article {26824,
	title = {The apiary at Tel Reḥov: An update\&rlm;.},
	journal = {Near Eastern Archaeology},
	volume = {85},
	number = {2},
	year = {2022},
	pages = {126-131},
	abstract = {The apiary discovered in Stratum V at Tel Reḥov in 2005{\textendash}2007 remains unique in the archaeology of the ancient Near East. Here the authors briefly summarize the data previously published in this journal and add results of new studies, mainly concerning the identification of ancient charred bees trapped in burnt honeycombs found in the hives. Measurements of two wings and one leg, and statistical work based on existing database of modern subspecies, are inconsistent with the Syrian subspecies local to Israel (Apis meliferra syriaca), but were found to be similar to the Anatolian bee (Apis meliferra anatoliaca). We discuss the implications of this result, suggesting trade relations with southern Anatolia. The authors suggest that the beeswax was perhaps related to the copper-based metallurgical industry that entailed casting in the lost wax method, at a time when the copper trade based on the Arabah mines was at its peak.},
	url = {https://doi.org/10.1086/719596},
	author = {Mazar, A and Panitz-Cohen, N and Bloch, G.}
}
@article {26706,
	title = {Earlier Morning Arrival to Pollen-Rewarding Flowers May Enable Feral Bumble Bees to Successfully Compete with Local Bee Species and Expand Their Distribution Range in a Mediterranean Habitat},
	journal = {Insects},
	volume = {13},
	number = {9},
	year = {2022},
	pages = {816},
	abstract = {During recent decades, bumble bees (Bombus terrestris) have continuously expanded their range in the Mediterranean climate regions of Israel. To assess their potential effects on local bee communities, we monitored their diurnal and seasonal activity patterns, as well as those of native bee species in the Judean Hills. We found that all bee species tend to visit pollen-providing flowers at earlier times compared to nectar-providing flowers. Bumble bees and honey bees start foraging at earlier times and colder temperatures compared to other species of bees. This means that the two species of commercially managed social bees are potentially depleting much of the pollen, which is typically non-replenished, before most local species arrive to gather it. Taking into consideration the long activity season of bumble bees in the Judean hills, their ability to forage at the low temperatures of the early morning, and their capacity to collect pollen at early hours in the dry Mediterranean climate, feral and range-expanding bumble bees potentially pose a significant competitive pressure on native bee fauna. Their effects on local bees can further modify pollination networks, and lead to changes in the local flora.},
	url = {https://www.mdpi.com/2075-4450/13/9/816/htm},
	author = {Noam Bar Shai and Motro, Uzi and Avishai Shmida and Bloch, Guy}
}
@article {26771,
	title = {Field-realistic concentrations of a neonicotinoid insecticide influence socially regulated brood development in a bumblebee},
	journal = {Proceedings of the Royal Society B},
	volume = {289},
	year = {2022},
	pages = {20220253},
	abstract = {The systemic neonicotinoid insecticides are considered as one of the key culprits contributing to ongoing declines in pollinator health and abundance. Bumblebees are among the most important pollinators of temperate zone plants, making their susceptibility to neonicotinoid exposure of great concern. We report that bumblebee (Bombus terrestris) colonies exposed to field-realistic concentrations of the commonly used neonicotinoid Imidacloprid grew slower, consumed less food, and produced fewer workers, males and gynes, but unexpectedly produced larger workers compared to control colonies. Behavioural observations show that queens in pesticide-treated colonies spend more time inactive and less time caring for the brood. We suggest that the observed effects on brood body size are driven by a decreased queen ability to manipulate the larva developmental programme. These findings reveal an intricate and previously unknown effect of insecticides on the social interactions controlling brood development in social insect colonies. Insecticide influences on the social mechanisms regulating larval development are potentially detrimental for bumblebees, in which body size strongly influences both caste differentiation and the division of labour among workers, two organization principles of insect societies},
	url = {https://royalsocietypublishing.org/doi/10.1098/rspb.2022.0253},
	author = {Hanna Chole and Miguel de Guinea and Woodard, S. Hollis and Bloch, Guy}
}
@article {26683,
	title = {The influences of illumination regime on egg-laying rhythms of honey bee queens},
	journal = {Journal of Biological Rhythms},
	year = {2022},
	abstract = {Honey bee queens show extreme fecundity, commonly laying more than a thousand eggs in a single day. It has proven challenging to study the temporal organization of egg-laying behavior because queens are typically active around the clock in the dark cavity of a densely populated nest. To contend with this challenge, we developed two novel methods allowing detailed monitoring of queen activity and egg-laying. We first adapted a high-resolution, continuous, tracking system allowing to track the position of barcode-tagged queens in observation hives with colonies foraging outside. We found that the queen is active  96\% of the day with typically no diurnal rhythm. Next, we developed a new laboratory procedure to monitor egg-laying at single egg resolution under different light regimes. We found that under constant darkness (DD) and temperature conditions, queens laid eggs with no circadian rhythms. Queen fecundity was severely reduced under constant light (LL). Under a 12:12 illumination regime, queen fecundity was comparable to under constant darkness, with a higher number of eggs during the light phase. These daily rhythms in egg-laying continued when these queens were released to DD conditions, suggesting that egg-laying rhythms are influenced by endogenous circadian clocks. These results suggest that honey bee queens are active and lay eggs around the clock with no diurnal rhythms. Light has complex influences on these behaviors, but more studies are needed to determine whether these effects reflect the influence of light directly on the queen or indirectly by affecting workers that interact with the queen.},
	url = {https://journals.sagepub.com/doi/10.1177/07487304221126782},
	author = {Shpigler, Hagai Y. and Almog Yaniv and Tim Gernat and Robinson, Gene E. and Bloch, Guy}
}
@article {insects12030236,
	title = {Body Size and Behavioural Plasticity Interact to Influence the Performance of Free-Foraging Bumble Bee Colonies},
	journal = {Insects},
	volume = {12},
	number = {3},
	year = {2021},
	abstract = {Specialisation and plasticity are important for many forms of collective behaviour, but the interplay between these factors is little understood. In insect societies, workers are often developmentally primed to specialise in different tasks, sometimes with morphological or physiological adaptations, facilitating a division of labour. Workers may also plastically switch between tasks or vary their effort. The degree to which developmentally primed specialisation limits plasticity is not clear and has not been systematically tested in ecologically relevant contexts. We addressed this question in 20 free-foraging bumble bee (Bombus terrestris) colonies by continually manipulating colonies to contain either a typically diverse, or a reduced ({\textquotedblleft}homogeneous{\textquotedblright}), worker body size distribution while keeping the same mean body size, over two trials. Pooling both trials, diverse colonies produced a larger comb mass, an index of colony performance. The link between body size and task was further corroborated by the finding that foragers were larger than nurses even in homogeneous colonies with a very narrow body size range. However, the overall effect of size diversity stemmed mostly from one trial. In the other trial, homogeneous and diverse colonies showed comparable performance. By comparing behavioural profiles based on several thousand observations of individuals, we found evidence that workers in homogeneous colonies in this trial rescued colony performance by plastically increasing behavioural specialisation and/or individual effort, compared to same-sized individuals in diverse colonies. Our results are consistent with a benefit to colonies of large and small specialists under certain conditions, but also suggest that plasticity or effort can compensate for reduced (size-related) specialisation. Thus, we suggest that an intricate interplay between specialisation and plasticity is functionally adaptive in bumble bee colonies.},
	issn = {2075-4450},
	doi = {10.3390/insects12030236},
	url = {https://www.mdpi.com/2075-4450/12/3/236},
	author = {Holland, Jacob G. G. and Nakayama, Shinnosuke and Porfiri, Maurizio and Nov, Oded and Bloch, Guy}
}
@article {25379,
	title = {Care-giver identity impacts offspring development and performance in an annually social bumble bee},
	volume = {21},
	number = {1},
	year = {2021},
	month = {2021},
	pages = {20},
	abstract = {The developmental fates of offspring have the potential to be influenced by the identity of their care-givers and by the nature of the care that they receive. In animals that exhibit both parental and alloparental care, such as the annually eusocial insects, the influence of care-giver identity can be directly assessed to yield mechanistic and evolutionary insights into the origins and elaboration of brood care. Here, we performed a comparative investigation of maternal and worker brood care in bumble bees, a pollinator group where mothers (queens) rear the first offspring in the nest, and then daughters (workers) assume this role upon their emergence. Specifically, we compared the effects of queen and worker brood care on offspring development and also offspring performance, for a set of traits related to sensory biology, learning, and stress resistance.},
	isbn = {2730-7182},
	url = {https://doi.org/10.1186/s12862-021-01756-2},
	author = {Costa, Claudin{\'e}ia P. and Fisher, Kaleigh and Guill{\'e}n, Blanca M. and Yamanaka, Naoki and Bloch, Guy and Woodard, S. Hollis}
}
@article {26142,
	title = {Kr{\"u}ppel-homologue 1 mediates hormonally-regulated dominance rank in a social bee},
	journal = {Biology (MDPI)},
	volume = {10},
	number = {11},
	year = {2021},
	month = {Nov 2021},
	pages = {1188},
	abstract = {Dominance hierarchies are ubiquitous in invertebrates and vertebrates, but little is known on how genes influence dominance rank. Our gaps in knowledge are specifically significant concerning female hierarchies, and in insects. To start filling these gaps, we studied the social bumble bee Bombus terrestris, in which social hierarchies among females are common and functionally significant. Dominance rank in this bee is influenced by multiple factors, including juvenile hormone (JH) that is a major gonadotropin in this species. We tested the hypothesis that the JH responsive transcription factor Kr{\"u}ppel homologue 1 (Kr-h1) mediates hormonal influences on dominance behavior. We first developed and validated a perfluorocarbon nanoparticles-based RNA interference protocol for knocking down Kr-h1 expression. We then used this procedure to show that Kr-h1 mediates the influence of JH not only on oogenesis and wax production, but also on aggression and dominance rank. To the best of our knowledge, this is the first study causally linking a gene to dominance rank in social insects, and one of only a few such studies in insects or in female hierarchies. These findings are important for determining whether there are general molecular principles governing dominance rank across gender and taxa.},
	url = {https://www.mdpi.com/2079-7737/10/11/1188},
	author = {Pandey, Atul and Bloch, Guy}
}
@article {26157,
	title = {Remarkable sensitivity of young honey bee workers to multiple non-photic, non-thermal, forager cues that synchronize their daily activity rhythms},
	journal = {Frontiers in Physiology-Chronobiology},
	volume = {12},
	year = {2021},
	month = {19 Nov 2021},
	pages = {2249},
	abstract = {Honey bees live in colonies containing tens of thousands of workers that coordinate their activities to produce efficient colony-level behavior. In free-foraging colonies, nest bees are entrained to the forager daily phase of activity even when experiencing conflicting light-dark illumination regime, but little is known on the cues mediating this potent social synchronization. We monitored locomotor activity in an array of individually caged bees in which we manipulated the contact with neighbour bees. We used circular statistics and coupling function analyses to estimate the degree of social synchronization. We found that young bees in cages connected to cages housing foragers showed stronger rhythms, better synchronization with each other, higher coupling strength, and a phase more similar to that of the foragers compared to similar bees in unconnected cages. These findings suggest that close distance contacts are sufficient for social synchronization or that cage connection facilitated the propagation of time-giving social cues. Coupling strength was higher for bees placed on the same tray compared with bees at a similar distance but on a different tray, consistent with the hypothesis that substrate borne vibrations mediate phase synchronization. Additional manipulation of the contact between cages showed that social synchronization is better among bees in cages connected with tube with a single mesh partition compared to sealed tubes consistent with the notion that volatile cues act additively to substrate borne vibrations. These findings are consistent with self-organization models for social synchronization of activity rhythms and suggest that the circadian system of honey bees evolved remarkable sensitivity to non-photic, non-thermal, time giving entraining cues enabling them to tightly coordinate their behavior in the dark and constant physical environment of their nests.},
	url = {https://www.frontiersin.org/articles/10.3389/fphys.2021.789773/abstract},
	author = {Oliver Seihler and Wang, Shuo and Bloch, Guy}
}
@article {25773,
	title = {Social synchronization of circadian rhythms with a focus on honeybees},
	journal = {Phil. Trans. R. Soc. B},
	volume = {376},
	year = {2021},
	pages = {20200342},
	abstract = {Many animals benefit from synchronizing their daily activities with conspecifics. In this hybrid paper, we first review recent literature supporting and extending earlier evidence for a lack of clear relationship between the level of sociality and social entrainment of circadian rhythms. Social entrainment is specifically potent in social animals that live in constant environments in which some or all individuals do not experience the ambient day-night cycles. We next focus on highly social honeybees in which there is good evidence that social cues entrain the circadian clocks of nest bees and can override the influence of conflicting light-dark cycles. The current understanding of social synchronization in honeybees is consistent with self-organization models in which surrogates of forager activity, such as substrate-borne vibrations and colony volatiles, entrain the circadianclocks of bees dwelling in the dark cavity of the nest. Finally, we present original findings showing that social synchronization is effective even in an array of individually caged callow bees placed on the same substrate and is improved for bees in connected cages. These findings reveal remarkable sensitivity to social time-giving cues and show that bees with attenuated rhythms (weak oscillators) can nevertheless be socially synchronized to acommon phase of activity.This article is part of the theme issue {\textquoteleft}Synchrony and rhythm interaction: from the brain to behavioural ecology{\textquoteright}.},
	url = {https://doi.org/10.1098/rstb.2020.0342},
	author = {Siehler, Oliver and Wang, Shuo and Bloch, Guy}
}
@article {Kapheim730317,
	title = {Brain microRNAs among social and solitary bees},
	journal = {Royal Society Open Science},
	volume = {7},
	number = {7},
	year = {2020},
	pages = {200517},
	publisher = {Cold Spring Harbor Laboratory},
	abstract = {Evolutionary transitions to a social lifestyle in insects are associated with lineage-specific changes in gene expression, but the key nodes that drive these regulatory changes are unknown. We examined the relationship between social organization and lineage-specific microRNAs (miRNAs). Genome scans across 12 bee species showed that miRNA copy-number is mostly conserved and not associated with sociality. However, deep sequencing of small RNAs in six bee species revealed a substantial proportion (20-35\%) of detected miRNAs had lineage-specific expression in the brain, 24-72\% of which did not have homologs in other species. Lineage-specific miRNAs disproportionately target lineage-specific genes, and have lower expression levels than shared miRNAs. The predicted targets of lineage-specific miRNAs are not enriched for genes with caste-biased expression or genes under positive selection in social species. Together, these results suggest that novel miRNAs may coevolve with novel genes, and thus contribute to lineage-specific patterns of evolution in bees, but do not appear to have significant influence on social evolution. Our analyses also support the hypothesis that many new miRNAs are purged by selection due to deleterious effects on mRNA targets, and suggest genome structure is not as influential in regulating bee miRNA evolution as has been shown for mammalian miRNAs.},
	doi = {10.1101/730317},
	url = {https://royalsocietypublishing.org/doi/10.1098/rsos.200517},
	author = {Kapheim, Karen M. and Jones, Beryl M. and S{\o}vik, Eirik and Stolle, Eckart and Waterhouse, Robert M. and Bloch, Guy and Ben-Shahar, Yehuda}
}
@article {24495,
	title = {Circadian plasticity in honey bees},
	journal = {Biochem (Lond)},
	volume = {42},
	number = {2},
	year = {2020},
	month = {2020/03/31/},
	pages = {22 - 26},
	abstract = {Circadian rhythms of about a day are ubiquitous in animals and considered functionally significant. Honey bees show remarkable circadian plasticity that is related to the complex social organization of their societies. Forager bees show robust circadian rhythms that support time-compensated sun-compass navigation, dance communication and timing visits to flowers. Nest-dwelling nurse bees care for the young brood around the clock. Here, we review our current understanding of the molecular and neuroanatomical mechanisms underlying this remarkable natural plasticity in circadian rhythms.},
	isbn = {0954-982X},
	url = {https://doi.org/10.1042/BIO04202002},
	author = {Beer, Katharina and Bloch, Guy}
}
@article {Siehler850891,
	title = {Colony Volatiles and Substrate-borne Vibrations Entrain Circadian Rhythms and Are Potential Cues Mediating Social Synchronization in Honey Bee Colonies},
	journal = {Journal of Biological Rhythms},
	volume = {35},
	number = {3},
	year = {2020},
	pages = {246-256},
	publisher = {Cold Spring Harbor Laboratory},
	abstract = {Internal circadian clocks organize animal behavior and physiology and are entrained by ecologically relevant external time-givers such as light and temperature cycles. In the highly social honey bee, social time-givers are potent and can override photic entrainment, but the cues mediating social entrainment are unknown. Here, we tested whether substrate-borne vibrations and hive volatiles can mediate social synchronization in honey bees. We first placed newly emerged worker bees on the same or on a different substrate on which we placed cages with foragers entrained to ambient day-night cycles, while minimizing the spread of volatiles between cages. In the second experiment, we exposed young bees to constant airflow drawn from either a free-foraging colony or a similar-size control hive containing only heated empty honeycombs, while minimizing transfer of substrate-borne vibrations between cages. After 6 days, we isolated each focal bee in an individual cage in an environmental chamber and monitored her locomotor activity. We repeated each experiment 5 times, each trial with bees from a different source colony, monitoring a total of more than 1000 bees representing diverse genotypes. We found that bees placed on the same substrate as foragers showed a stronger phase coherence and a phase more similar to that of foragers compared with bees placed on a different substrate. In the second experiment, bees exposed to air drawn from a colony showed a stronger phase coherence and a phase more similar to that of foragers compared with bees exposed to air from an empty hive. These findings lend credence to the hypothesis that surrogates of activity entrain circadian rhythms and suggest that multiple social cues can act in concert to entrain social insect colonies to a common phase.},
	doi = {10.1101/850891},
	url = {https://journals.sagepub.com/eprint/VFC2SEWBEKSCAJYITK7K/full},
	author = {Siehler, Oliver and Bloch, Guy}
}
@article {24668,
	title = {The complexity of social complexity: a quantitative multidimensional approach for studies on social organisation},
	journal = {The American Naturalist},
	volume = {196},
	number = {5},
	year = {2020},
	abstract = {\&nbsp;The rapid increase in {\textquotedblleft}big data{\textquotedblright} of the post-genomic era makes it crucial to appropriately measure the level of social complexity in comparative studies. We argue that commonly-used qualitative classifications lump together species showing a broad range of social complexity, and falsely imply that social evolution always progresses along a single linear stepwise trajectory that can be deduced from comparing extant species. To illustrate this point, we compared widely-used social complexity measures in "primitively social" bumble bees with {\textquotedblleft}advanced eusocial{\textquotedblright} stingless bees, honey bees, and attine ants. We find that a single species can have both higher and lower levels of complexity compared to other taxa, depending on the social trait measured. We propose that measuring the complexity of individual social traits switches focus from semantic discussions and offers several directions for progress. Firstly, quantitative social traits can be correlated with molecular, developmental, and physiological processes within and across lineages of social animals. This approach is particularly promising for identifying processes that influence or have been affected by social evolution. Secondly, key social complexity traits can be combined into multidimensional lineage-specific quantitative indices enabling fine scale comparison across species that are currently bundled within the same level of social complexity.\&nbsp;},
	url = {https://www.journals.uchicago.edu/doi/abs/10.1086/710957},
	author = {Holland, Jacob G. and Bloch, Guy}
}
@article {PANDEY2020100056,
	title = {Juvenile hormone affects the development and strength of circadian rhythms in young bumble bee (Bombus terrestris) workers},
	journal = {Neurobiology of Sleep and Circadian Rhythms},
	year = {2020},
	pages = {100056},
	abstract = {The circadian and endocrine systems influence many physiological processes in animals, but little is known on the ways they interact in insects. We tested the hypothesis that juvenile hormone (JH) influences circadian rhythms in the social bumble bee Bombus terrestris. JH is the major gonadotropin in this species coordinating processes such as vitellogenesis, oogenesis, wax production, and behaviors associated with reproduction. It is unknown however, whether it also influences circadian processes. We topically treated newly-emerged bees with the allatoxin Precocene-I (P-I) to reduce circulating JH titers and applied the natural JH (JH-III) for replacement therapy. We repeated this experiment in three trials, each with bees from different source colonies. Measurements of ovarian activity suggest that our JH manipulations were effective; bees treated with P-I had inactive ovaries, and this effect was fully recovered by subsequent JH treatment. We found that JH augments the strength of circadian rhythms and the pace of rhythm development in individually isolated newly emerged worker bees. JH manipulation did not affect the free-running circadian period, overall level of locomotor activity, sleep amount, or sleep structure. Given that acute manipulation at an early age produced relatively long-lasting effects, we propose that JH effects on circadian rhythms are mostly organizational, accelerating the development or integration of the circadian system.},
	keywords = {Bumble bee, Circadian rhythms, Gonadotropin, Hormone, Juvenile hormone, Locomotor activity, sleep},
	issn = {2451-9944},
	doi = {https://doi.org/10.1016/j.nbscr.2020.100056},
	url = {http://www.sciencedirect.com/science/article/pii/S2451994420300080},
	author = {Pandey, Atul and Motro, Uzi and Bloch, Guy}
}
@article {Pandey626382,
	title = {Juvenile hormone interacts with multiple factors to modulate aggression and dominance in a social bumblebee},
	journal = {Hormones and Behavior},
	volume = {117},
	year = {2020},
	pages = {104602},
	publisher = {Cold Spring Harbor Laboratory},
	abstract = {Juvenile hormone (JH) is a key regulator of insect development and reproduction. Given that JH commonly affects adult insect fertility, it has been hypothesized to also regulate behaviors such as dominance and aggression that are associated with reproduction. We tested this hypothesis in the bumblebee Bombus terrestris for which JH has been shown to be the major gonadotropin. We used the allatoxin precocene-I (P-I) to reduce hemolymph JH titers and replacement therapy with JH-III to revert this effect. In small orphan groups of workers with similar body size but mixed treatment, P-I treated bees showed lower aggressiveness, oogenesis, and dominance rank compared with control and replacement therapy treated bees. In similar groups in which all bees were treated similarly, there was a clear dominance hierarchy, even in P-I and replacement therapy groups in which the bees showed similar levels of ovarian activation. In a similar experiment in which bees differed in body size, larger bees were more likely to be dominant despite their similar JH treatment and ovarian state. In the last experiment, we show that JH manipulation does not affect dominance rank in groups that had already established a stable dominance hierarchy. These findings solve previous ambiguities concerning whether or not JH affects dominance in bumblebees. JH positively affects dominance, but bees with similar levels of JH can nevertheless establish dominance hierarchies. Thus, multiple factors including JH, body size, and previous experience affect dominance and aggression in social bumblebees.},
	doi = {10.1101/626382},
	url = {https://www.sciencedirect.com/science/article/pii/S0018506X19301886?dgcid=author},
	author = {Pandey, Atul and Motro, Uzi and Bloch, Guy}
}
@article {SHPIGLER2020104844,
	title = {Juvenile hormone regulates brain-reproduction tradeoff in bumble bees but not in honey bees},
	journal = {Hormones and Behavior},
	volume = {126},
	year = {2020},
	pages = {104844},
	abstract = {Gonadotropic hormones coordinate processes in diverse tissues regulating animal reproductive physiology and behavior. Juvenile hormone (JH) is the ancient and most common gonadotropin in insects, but not in advanced eusocial honey bees and some ants. To start probing the evolutionary basis of this change, we combined endocrine manipulations, transcriptomics, and behavioral analyses to study JH regulated processes in a bumble bee showing a relatively simple level of eusociality. We found that in worker fat body, more JH-regulated genes were up- rather than down-regulated, and enriched for metabolic and biosynthetic pathways. This transcriptomic pattern is consistent with earlier evidence that JH is the major gonadotropin in bumble bees. In the brain, more JH-regulated genes were down- rather than up-regulated and enriched for protein turnover pathways. Brain ribosomal protein gene expression shows a similar trend of downregulation in dominant workers, which naturally have high JH titers. In other species, similar downregulation of protein turnover is found in aging brains or under stress, associated with compromised long-term memory and health. These findings suggest a previously unknown gonadotropin-mediated tradeoff. Analysis of published data reveals no such downregulation of protein turnover pathways in the brain of honey bee workers, which exhibit more complex eusociality and in which JH is not a gonadotropin but rather regulates division of labor. These results suggest that the evolution of complex eusociality in honey bees was associated with modifications in hormonal signalling supporting extended and extremely high fertility while reducing the ancient costs of high gonadotropin titers to the brain.},
	keywords = {Bees, Functional genomics, Gonadotropin, Juvenile hormone, Social evolution},
	issn = {0018-506X},
	doi = {https://doi.org/10.1016/j.yhbeh.2020.104844},
	url = {http://www.sciencedirect.com/science/article/pii/S0018506X20301707},
	author = {Shpigler, Hagai Y. and Herb, Brian and Drnevich, Jenny and Band, Mark and Robinson, Gene E. and Bloch, Guy}
}
@article {Merling673509,
	title = {Worker body size but not its age influences phototaxis in a bumblebee (Bombus terrestris, L.)},
	journal = {Apidologie},
	volume = {51},
	year = {2020},
	pages = {763{\textendash}776},
	publisher = {Cold Spring Harbor Laboratory},
	abstract = {We studied phtototaxis, the directional movement relative to light in the bumblebee Bombus terrestris. We first developed and validated a MATLAB based system enabling reliable high-resolution tracking of a bumblebee relative to a changing LED light source. Our tracking protocol enables us to separate the phototaxis response from simple directional movement, overall levels of locomotor activity, or arousal state. We next used this system to compare the phototactic response of workers varying in their body size, age, or task performance. In all our experiments the bees showed a positive phototaxis. The strength of the phototactic response was influenced by body size but not age, and this effect was significant when the light source was weak. In one of two trials foragers that were larger showed stronger phototactic response than nurses when tested with the weak light source. Taken together, the evidence that phototaxis is associated with size-based division of labor in the bumblebee and with age-related division of labor in the honeybee, lend credence to response threshold models implicating the response to light in the organization of division of labor in cavity dwelling social insect.},
	doi = {10.1101/673509},
	url = {https://link.springer.com/article/10.1007/s13592-020-00759-0?wt_mc=Internal.Event.1.SEM.ArticleAuthorOnlineFirst},
	author = {Merling, Michal and Eisenmann, Shmuel and Bloch, Guy}
}
@article {CHOLE2019,
	title = {Body size variation in bees: regulation, mechanisms, and relationship to social organization},
	journal = {Current Opinion in Insect Science},
	volume = {35},
	year = {2019},
	pages = {77-87},
	abstract = {Size polymorphism is common in bees, and is determined by environmental factors such as temperature, brood cell size, and the diet provided to developing larvae. In social bees, these factors are further influenced by intricate interactions between the queen, workers, and the developing brood which eventually determine the final size and caste of developing larvae. Environmental and social factors act in part on juvenile hormone and ecdysteroids, which are key hormonal regulators of body size and caste determination. In some social bees, body size variation is central for social organization because it structures reproductive division of labor, task allocation among workers, or both. At ecological scales, body size also impacts bee-mediated pollination services in solitary and social species by influencing floral visitation and pollination efficacy.},
	issn = {2214-5745},
	doi = {https://doi.org/10.1016/j.cois.2019.07.006},
	url = {http://www.sciencedirect.com/science/article/pii/S2214574518302062},
	author = {Hanna Chole and Woodard, S. Hollis and Bloch, Guy}
}
@article {Nagari500744,
	title = {Bumble bee workers give up sleep to care for offspring that are not their own},
	journal = {Current Biology},
	year = {2019},
	publisher = {Cold Spring Harbor Laboratory},
	abstract = {Sleep is ubiquitous in vertebrates and invertebrates and its loss is typically associatedwith reduced performance, health, or survival, for reasons that are yet unclear [1{\textemdash}3].Nevertheless, some animals can reduce sleep for increasing foraging time [4], underpredation risk [5{\textemdash}8], during \&nbsp;seasonal migration [9{\textemdash}11], or for having greater matingopportunities [12,13]. Here we tested the hypothesis that social bumble bee (Bombusterrestris) workers give-up sleep for improving brood-care. We combined video-recordings, detailed behavioral analyses, sleep-deprivation experiments, andresponse-threshold assessments, to characterize the sleep behavior of worker beesand showed that immobility bouts of >= 5{\textquoteright} provide a reliable proxy for sleep. We nextused this index to study sleep with an automated video-based activity monitoringsystem. We found that isolated workers severely reduce sleep time in the presence ofboth larvae that need to be fed, or pupae that do not. Reduced sleep was alsocorrelated with around-the-clock activity and wax-pot building, which are typical fornest-founding mother queens. Cocoons, from which we removed the pupae, elicited asimilar but transient sleep-loss in tending workers, suggesting that the pupa effect onsleep is mediated by pheromonal signals. Sleep time increased following broodremoval, but remained lower compared to control bees, suggesting that the broodmodulated sleep-need. This first evidence for brood modulation of sleep in an insectsuggests that plasticity in sleep can evolve as a mechanism to improve care fordependent juveniles, even in social insect workers that do not care for their ownoffspring.},
	doi = {10.1101/500744},
	url = {https://www.cell.com/current-biology/fulltext/S0960-9822(19)31017-6?_returnURL=https\%3A\%2F\%2Flinkinghub.elsevier.com\%2Fretrieve\%2Fpii\%2FS0960982219310176\%3Fshowall\%3Dtrue},
	author = {Nagari, Moshe and Gera, Ariel and Jonsson, Sara and Bloch, Guy}
}
@article {23405,
	title = {RNA editing is abundant and correlates with task performance in a social bumblebee},
	journal = {Nature Communications},
	volume = {10},
	number = {1},
	year = {2019},
	month = {2019},
	pages = {1605},
	abstract = {Colonies of the bumblebee Bombus terrestris are characterized by wide phenotypic variability among genetically similar full-sister workers, suggesting a major role for epigenetic processes. Here, we report a high level of ADAR-mediated RNA editing in the bumblebee, despite the lack of an ADAR1-homolog. We identify 1.15 million unique genomic sites, and 164 recoding sites residing in 100 protein coding genes, including ion channels, transporters, and receptors predicted to affect brain function and behavior. Some edited sites are similarly edited in other insects, cephalopods and even mammals. The global editing level of protein coding and non-coding transcripts weakly correlates with task performance (brood care vs. foraging), but not affected by dominance rank or juvenile hormone known to influence physiology and behavior. Taken together, our findings show that brain editing levels are high in naturally behaving bees, and may be regulated by relatively short-term effects associated with brood care or foraging activities.},
	isbn = {2041-1723},
	url = {https://doi.org/10.1038/s41467-019-09543-w},
	author = {Porath, Hagit T. and Hazan, Esther and Shpigler, Hagai and Cohen, Mira and Band, Mark and Ben-Shahar, Yehuda and Levanon, Erez Y. and Eisenberg, Eli and Bloch, Guy}
}
@article {Wang201721286,
	title = {Inferring dynamic topology for decoding spatiotemporal structures in complex heterogeneous networks},
	journal = {Proceedings of the National Academy of Sciences},
	year = {2018},
	publisher = {National Academy of Sciences},
	abstract = {Inferring connections forms a critical step toward understanding large and diverse complex networks. To date, reliable and efficient methods for the reconstruction of network topology from measurement data remain a challenge due to the high complexity and nonlinearity of the system dynamics. These obstacles also form a bottleneck for analyzing and controlling the dynamic structures (e.g., synchrony) and collective behavior in such complex networks. The novel contribution of this work is to develop a unified data-driven approach to reliably and efficiently reveal the dynamic topology of complex networks in different scales{\textemdash}from cells to societies. The developed technique provides guidelines for the refinement of experimental designs toward a comprehensive understanding of complex heterogeneous networks.Extracting complex interactions (i.e., dynamic topologies) has been an essential, but difficult, step toward understanding large, complex, and diverse systems including biological, financial, and electrical networks. However, reliable and efficient methods for the recovery or estimation of network topology remain a challenge due to the tremendous scale of emerging systems (e.g., brain and social networks) and the inherent nonlinearity within and between individual units. We develop a unified, data-driven approach to efficiently infer connections of networks (ICON). We apply ICON to determine topology of networks of oscillators with different periodicities, degree nodes, coupling functions, and time scales, arising in silico, and in electrochemistry, neuronal networks, and groups of mice. This method enables the formulation of these large-scale, nonlinear estimation problems as a linear inverse problem that can be solved using parallel computing. Working with data from networks, ICON is robust and versatile enough to reliably reveal full and partial resonance among fast chemical oscillators, coherent circadian rhythms among hundreds of cells, and functional connectivity mediating social synchronization of circadian rhythmicity among mice over weeks.},
	issn = {0027-8424},
	doi = {10.1073/pnas.1721286115},
	url = {http://www.pnas.org/content/early/2018/08/23/1721286115},
	author = {Wang, Shuo and Herzog, Erik D. and Kiss, Istv{\'a}n Z. and Schwartz, William J. and Bloch, Guy and Sebek, Michael and Granados-Fuentes, Daniel and Wang, Liang and Li, Jr-Shin}
}
@article {10.3389/fevo.2018.00016,
	title = {The Influence of Social Information and Self-expertise on Emergent Task Allocation in Virtual Groups},
	journal = {Frontiers in Ecology and Evolution},
	volume = {6},
	year = {2018},
	pages = {16},
	abstract = {Dynamic group coordination facilitates adaptive division of labor in response to group-level changes. Yet, little is known about how it can be operationalized in online collaborations among individuals with limited information about each other. We hypothesized that simple social information about the task distribution of others can elicit emergent task allocation. We conducted an online experiment where participants analyze images of a polluted canal by freely switching between two tasks: creating keyword-based tags for images and categorizing existing tags. During the task execution, we presented experimentally manipulated information about the contrasting group-level task distributions. Participants did not change the effort allocation between the tasks when they were notified that the group deficits workers in the task they intrinsically prefer. By contrast, they allocated more effort to the less preferred task than they would intrinsically do when their intrinsic effort allocation counterbalances the current distribution of workers in the group. Such behavioral changes were observed more strongly among those with higher skills in the less preferred task. Our results demonstrate the possibility of optimizing group coordination through design interventions at the individual level that lead to spontaneous adaption of division of labor at the group level. When participants were provided information about the group-level task distribution, they tend to allocate more effort to the task against their intrinsic preference.},
	issn = {2296-701X},
	doi = {10.3389/fevo.2018.00016},
	url = {https://www.frontiersin.org/article/10.3389/fevo.2018.00016},
	author = {Nakayama, Shinnosuke and Diner, David and Holland, Jacob G. and Bloch, Guy and Porfiri, Maurizio and Nov, Oded}
}
@article {Beer170224,
	title = {Pigment-Dispersing Factor-expressing neurons convey circadian information in the honey bee brain},
	journal = {Open Biology},
	volume = {8},
	number = {1},
	year = {2018},
	publisher = {Royal Society Journals},
	abstract = {Pigment-Dispersing Factor (PDF) is an important neuropeptide in the brain circadian network of Drosophila and other insects, but its role in bees in which the circadian clock influences complex behaviour is not well understood. We combined high-resolution neuroanatomical characterizations, quantification of PDF levels over the day and brain injections of synthetic PDF peptide to study the role of PDF in the honey bee Apis mellifera. We show that PDF co-localizes with the clock protein Period (PER) in a cluster of laterally located neurons and that the widespread arborizations of these PER/PDF neurons are in close vicinity to other PER-positive cells (neurons and glia). PDF-immunostaining intensity oscillates in a diurnal and circadian manner with possible influences for age or worker task on synchrony of oscillations in different brain areas. Finally, PDF injection into the area between optic lobes and the central brain at the end of the subjective day produced a consistent trend of phase-delayed circadian rhythms in locomotor activity. Altogether, these results are consistent with the hypothesis that PDF is a neuromodulator that conveys circadian information from pacemaker cells to brain centres involved in diverse functions including locomotion, time memory and sun-compass orientation.},
	doi = {10.1098/rsob.170224},
	url = {http://rsob.royalsocietypublishing.org/content/8/1/170224},
	author = {Beer, Katharina and Kolbe, Esther and Kahana, Noa B. and Yayon, Nadav and Weiss, Ron and Menegazzi, Pamela and Bloch, Guy and Helfrich-F{\"o}rster, Charlotte}
}
@article {doi:10.1111/desc.12665,
	title = {Prosocial and self-interested intra-twin pair behavior in monozygotic and dizygotic twins in the early to middle childhood transition},
	journal = {Developmental Science},
	volume = {21},
	number = {6},
	year = {2018},
	pages = {e12665},
	abstract = {Abstract Several related and complementary theoretical frameworks have been proposed to explain the existence of prosocial behavior, despite its potential fitness cost to the individual. These include kin selection theory, proposing that organisms have a propensity to help those to whom they are genetically related, and reciprocity, referring to the benefit of being prosocial, depending on past and future mutual interactions. A useful paradigm to examine prosociality is to compare mean levels of this behavior between monozygotic (MZ) and dizygotic (DZ) twins. Here, we examined the performance of 883 6.5-year-old twins (139 MZ and 302 DZ same-sex 6.5-year-old full twin pairs) in the Differential Productivity Task. In this task, the twins{\textquoteright} behaviors were observed under two conditions: working for themselves vs. working for their co-twin. There were no significant differences between the performances of MZ and DZ twins in the prosocial condition of the task. Correlations within the twin dyads were significantly higher in MZ than DZ twins in the self-interested condition. However, similar MZ and DZ correlations were found in the prosocial condition, supporting the role of reciprocity in twins{\textquoteright} prosociality towards each other.},
	doi = {10.1111/desc.12665},
	url = {https://onlinelibrary.wiley.com/doi/full/10.1111/desc.12665},
	author = {Karen Yirmiya and Nancy L. Segal and Bloch, Guy and Ariel Knafo-Noam}
}
@article {18156,
	title = {Capped-brood, which does not require feeding, is tended around-the-clock by nurse honeybee works},
	journal = {The Journal of Experimental Biology},
	volume = {220},
	year = {2017},
	pages = {4130-4140},
	abstract = {{\textquotedblleft}Nurse{\textquotedblright} honeybees tend brood around-the-clock with attenuated or no circadian rhythms, but the brood signals inducing this behavior remain elusive.\&nbsp; We first tested the hypothesis that worker circadian rhythms are regulated by brood pheromones. We monitored locomotor activity of individually isolated nurse bees that were either exposed to various doses of larval extracts or synthetic brood ester pheromone (BEP). Bees orally treated with larvae extracts showed attenuated circadian rhythms in one of four\&nbsp;tested trials; a similar but statistically non-significant trend was seen in two an additional trial. Nurse bees treated with synthetic BEP showed rhythm attenuation in one of three trials. Next, we tested the hypothesis that capped brood, which does not require feeding, is nevertheless tended around-the-clock by nurse. By combining a new protocol that enables brood care by individually isolated nurse bees, detailed behavioral observations, and automatic high resolution monitoring of locomotor activity, we found that isolated nurses tended capped brood around-the-clock with attenuated circadian rhythms. Bees individually isolated in similar cages but without brood, showed strong circadian rhythms in locomotor activity and rest. This study shows for the first time that the need to feed hungry larvae is not the only factor accounting for around-the-clock activity in nurse bees. Our results further suggest that the transition between activity with and without circadian rhythms is not a simple switch triggered by brood pheromones. Around-the-clock tending may enhance brood development and health in multiple ways that may include improved larval feeding, thermoregulation and hygienic behavior.\&nbsp;},
	url = {http://jeb.biologists.org/content/220/22/4130},
	author = {Nagari, Moshe and Brenner, Yafit and Bloch, Guy}
}
@inbook {15990,
	title = {Endocrine influences on insect societies},
	booktitle = {Hormones, Brain and Behavior},
	volume = {2},
	year = {2017},
	pages = {421-451},
	publisher = {Academic Press},
	organization = {Academic Press},
	edition = {3rd},
	address = {Oxford},
	abstract = {\&nbsp;Chapter Outline30.1 Introduction30.2 Overview of Division of Labor in Insect Societies\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.2.1 Division of Labor for Reproduction\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.2.2 Division of Labor among Workers\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.2.3 Primitive and Advanced Eusociality30.3 Insect Hormones That Influence Division of Labor30.4 Endocrine Signaling in Reproductive Division of Labor\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.4.1 JH and Reproductive Division of Labor\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.4.2 Ecdysone and Reproductive Division of Labor\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.4.3 Nutrition and Metabolic Factors Influencing Reproductive Division of Labor\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.4.4 Biogenic Amines and Reproductive Division of Labor30.5 Endocrine Influences on Division of Labor Among Workers: Behavioral Maturation\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.5.1 Juvenile Hormone and Behavioral Maturation\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.5.2 Ecdysone and Behavioral Maturation\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.5.3 Nutrition and Metabolic Factors Influencing Behavioral Maturation\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.5.4 Biogenic Amines and Behavioral Maturation30.6 Endocrine Influences on Division of Labor Among Workers: Morphologically Distinct Castes\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.6.1 Juvenile Hormone and Worker Caste Differentiation \&nbsp;30.7 The Transcriptomic Architecture Linking Endocrine Signaling and Behavioral State30.8 Evolutionary Perspectives\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.8.1 Endocrine-Related Signatures of Selection\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.8.2 Speculation on the Evolution of Division of Labor: A Neuroendocrine Perspective\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.8.3 Level One: Incipient Societies and Endocrine-Mediated Social Inhibition among Adults\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.8.4 Level Two: Pre-Adult Endocrine-Mediated Social Inhibition30.8.5 Level Three: Pre-Adult, Endocrine-Mediated Social Inhibition Enhanced by DisruptiveSelection\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp;\&nbsp; 30.8.6 Level Four: Division of Labor among Adult Workers and its Regulation by Endocrine-Mediated Social Inhibition30.8.7 Level Five: Division of Labor among Morphologically Distinct Adult Workers and ItsRegulation by Pre-Adult, Endocrine-Mediated Social Inhibition30.8.8 Concluding Remarks\&nbsp;},
	url = {DOI: 10.1016/B978-0-12-803592-4.00037-7},
	author = {Hamilton, Adam R and Shpigler, Hagai Y. and Bloch, Guy and Wheeler, Diana and Robinson, Gene E.}
}
@article {Fuchikawa170047,
	title = {Neuronal circadian clock protein oscillations are similar in behaviourally rhythmic forager honeybees and in arrhythmic nurses},
	journal = {Open Biology},
	volume = {7},
	year = {2017},
	publisher = {Royal Society Journals},
	abstract = {Internal clocks driving rhythms of about a day (circadian) are ubiquitous in animals, allowing them to anticipate environmental changes. Genetic or environmental disturbances to circadian clocks or the rhythms they produce are commonly associated with illness, compromised performance or reduced survival. Nevertheless, some animals including Arctic mammals, open sea fish and social insects such as honeybees are active around-the-clock with no apparent ill effects. The mechanisms allowing this remarkable natural plasticity are unknown. We generated and validated a new and specific antibody against the clock protein PERIOD of the honeybee Apis mellifera (amPER) and used it to characterize the circadian network in the honeybee brain. We found many similarities to Drosophila melanogaster and other insects, suggesting common anatomical organization principles in the insect clock that have not been appreciated before. Time course analyses revealed strong daily oscillations in amPER levels in foragers, which show circadian rhythms, and also in nurses that do not, although the latter have attenuated oscillations in brain mRNA clock gene levels. The oscillations in nurses show that activity can be uncoupled from the circadian network and support the hypothesis that a ticking circadian clock is essential even in around-the-clock active animals in a constant physical environment.},
	doi = {10.1098/rsob.170047},
	url = {http://rsob.royalsocietypublishing.org/content/7/6/170047},
	author = {Fuchikawa, T. and Beer, K. and Linke-Winnebeck, C. and Ben-David, R. and Kotowoy, A. and Tsang, V. W. K. and Warman, G. R. and Winnebeck, E. C. and Helfrich-F{\"o}rster, C. and Bloch, G.}
}
@article {17298,
	title = {Task-related phasing of circadian rhythms in antennal responsiveness to general odorants and pheromones in honeybees},
	journal = {Journal of Biological Rhythms},
	volume = {1},
	number = {1},
	year = {2017},
	month = {2017},
	pages = {11},
	abstract = {\&nbsp;The insect antennae receive olfactory information from the environment. In some insects it was shown that the antennal responsiveness is dynamically regulated by circadian clocks. However, it is unknown how general this phenomenon is and what functions it serves. Circadian regulation in honeybee workers is particularly interesting in this regard because they show natural task-related chronobiological plasticity. Forager bees show strong circadian rhythms in behavior and brain gene expression, whereas nurse bees tend brood around-the-clock and have attenuated circadian rhythms in activity and whole brain gene expression. Here we tested the hypothesis that there is task-related plasticity in circadian rhythms of antennal responsiveness to odorants in worker honeybees. We used electroantennogram (EAG) to measure the antennal responsiveness of nurses and foragers to general odorants and pheromones around the day. The capacity to track 10 Hz odorant pulses varied with time-of-day for both task-groups, but with different phases. The antennal pulse-tracking capacity was higher during the subjective day for the day-active foragers whereas it was better during the night for around-the-clock active nurses. The task-related phases of pulse-tracking rhythms were similar for all the tested stimuli. We also found evidence for circadian rhythms in the EAG response magnitude of foragers, but not of nurses. To the best of our knowledge, these results provide the first evidence for circadian regulation of antennal olfactory responsiveness and odorant pulse tracking capacity in bees, or any other hymenopteran insect. Importantly, our study shows for the first time that the circadian phase of olfactory responsiveness may be socially regulated.\&nbsp;},
	url = {http://journals.sagepub.com/doi/full/10.1177/0748730417733573$\#$articleCitationDownloadContainer},
	author = {Nagari, Moshe and Paul Szyszka and Giovanni Galizia and Bloch, Guy}
}
@article {18155,
	title = {Time is honey: circadian clocks of bees and flowers and how their interactions may influence ecological communities},
	journal = {Phil. Trans. R. Soc. B},
	volume = {20160256},
	year = {2017},
	abstract = {The interactions between flowering plants and insect pollinators shape eco-logical communities and provide one of the best examples of coevolution.Although these interactions have received much attention in both ecologyand evolution, their temporal aspects are little explored. Here we reviewstudies on the circadian organization of pollination-related traits in beesand flowers. Research, mostly with the honeybee, Apis mellifera, has impli-cated the circadian clock in key aspects of their foraging for flowerrewards. These include anticipation, timing of visits to flowers at specifiedlocations and time-compensated sun-compass orientation. Floral rhythmsin traits such as petal opening, scent release and reward availability alsoshow robust daily rhythms. However, in only few studies it was possibleto adequately determine whether these oscillations are driven by externaltime givers such as light and temperature cycles, or endogenous circadianclocks. The interplay between the timing of flowers and pollinators rhythmsmay be ecologically significant. Circadian regulation of pollination-relatedtraits in only few species may influence the entire pollination network andthus affect community structure and local biodiversity. We speculate thatthese intricate chronobiological interactions may be vulnerable to anthropo-genic effects such as the introduction of alien invasive species, pesticides orenvironmental pollutants Q1 .This article is part of the themed issue {\textquoteleft}Wild clocks: integrating chrono-biology and ecology to understand timekeeping in free-living animals{\textquoteright}.},
	url = {http://dx.doi.org/10.1098/rstb.2016.0256},
	author = {Bloch, Guy and Bar-Shai, Noam and Cytter, Yotam and Green, Rachel}
}
@article {18594,
	title = {Two sides of a coin: ecological and chronobiological perspectives of timing in the wild},
	journal = {Philosophical Transactions of the Royal Society B},
	volume = {20160246},
	year = {2017},
	abstract = {Most processes within organisms, and most interactions between organisms and their environment, have distinct time profiles. The temporal coordination of such processes is crucial across levels of biological organization, but diferent disciplines differ widely in their approaches to study timing. Such differences are accentuated between ecologists, who are centrally concerned with a holistic view of an organism in relation to its external environment, and chronobiologists, who emphasize internal timekeeping within an organism and the mechanisms of its adjustment to the environment. We argue that ecological and chronobiological perspectives are complementary, and that studies at the intersection will enable both fields to jointly overcome obstacles that currently hinder progress. However, to achieve this integration, we first have to cross some conceptual barriers, clarifying prohibitively inaccessible terminologies. We critically assess main assumptions and concepts in either field, as well as their common interests. Both approaches intersect in their need to understand the extent and regulation of temporal plasticity, and in the concept of {\textquoteleft}chronotype{\textquoteright}, i.e. the characteristic temporal properties of individuals which are the targets of natural and sexual selection. We then highlight promising developments, point out open questions, acknowledge difficulties and propose directions for further integration of ecological and chronobiological perspectives through Wild Clock research.This article is part of the themed issue {\textquoteleft}Wild Clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals{\textquoteright}.},
	url = {http://dx.doi.org/10.1098/rstb.2016.0246},
	author = {Helm, B and Visser, ME and Schwartz, W and Kronfeld-Schor, N and Gerkema, M and Piersma, T and Bloch, Guy}
}
@article { ISI:000383819400011,
	title = {No effect of juvenile hormone on task performance in a bumblebee (Bombus terrestris) supports an evolutionary link between endocrine signaling and social complexity},
	journal = {HORMONES AND BEHAVIOR},
	volume = {85},
	year = {2016},
	month = {SEP},
	pages = {67-75},
	abstract = {A hallmark of insect societies is a division of labor among workers specializing in different tasks. In bumblebees the division of labor is related to body size; relatively small workers are more likely to stay inside the nest and tend ({\textquoteright}{\textquoteright}nurse{\textquoteright}{\textquoteright}) brood, whereas their larger sisters are more likely to forage. Despite their ecological and economic importance, very little is known about the endocrine regulation of division of labor in bumblebees. We studied the influence of juvenile hormone OH) on task performance in the bumblebee Bombus terrestris. We first used a radioimmunoassay to measure circulating JH titers in workers specializing in nursing and foraging activities. Next, we developed new protocols for manipulating JH titers by combining a size-adjusted topical treatment with the allatotoxin Precocene-I and replacement therapy with JH-III. Finally, we used this protocol to test the influence of JH on task performance. JH levels were either similar for nurses and foragers (three colonies), or higher in nurses (two colonies). Nurses had better developed ovaries and JH levels were typically positively correlated with ovarian state. Manipulation of JH titers influenced ovarian development and wax secretion, consistent with earlier allatectomy studies. These manipulations however, did not affect nursing or foraging activity, or the likelihood to specialize in nursing or foraging activity. These findings contrast with honeybees in which JH influences age -related division of labor but not adult female fertility. Thus, the evolution of complex societies in bees was associated with modifications in the way JH influences social behavior. (C) 2016 Elsevier Inc. All rights reserved.},
	issn = {0018-506X},
	doi = {10.1016/j.yhbeh.2016.08.004},
	author = {Shpigler, Hagai Y. and Siegel, Adam J. and Huang, Zachary Y. and Bloch, Guy}
}
@article { ISI:000376204800001,
	title = {Potent social synchronization can override photic entrainment of circadian rhythms},
	journal = {NATURE COMMUNICATIONS},
	volume = {7},
	year = {2016},
	month = {MAY},
	abstract = {Circadian rhythms in behaviour and physiology are important for animal health and survival. Studies with individually isolated animals in the laboratory have consistently emphasized the dominant role of light for the entrainment of circadian rhythms to relevant environmental cycles. Although in nature interactions with conspecifics are functionally significant, social signals are typically not considered important time-givers for the animal circadian clock. Our results challenge this view. By studying honeybees in an ecologically relevant context and using a massive data set, we demonstrate that social entrainment can be potent, may act without direct contact with other individuals and does not rely on gating the exposure to light. We show for the first time that social time cues stably entrain the clock, even in animals experiencing conflicting photic and social environmental cycles. These findings add to the growing appreciation for the importance of studying circadian rhythms in ecologically relevant contexts.},
	issn = {2041-1723},
	doi = {10.1038/ncomms11662},
	author = {Fuchikawa, Taro and Eban-Rothschild, Ada and Nagari, Moshe and Shemesh, Yair and Bloch, Guy}
}
@article { ISI:000349404300017,
	title = {The colony environment modulates sleep in honey bee workers},
	journal = {JOURNAL OF EXPERIMENTAL BIOLOGY},
	volume = {218},
	year = {2015},
	month = {FEB},
	pages = {404-411},
	abstract = {One of the most important and evolutionarily conserved roles of sleep is the processing and consolidation of information acquired during wakefulness. In both insects and mammals, environmental and social stimuli can modify sleep physiology and behavior, yet relatively little is known about the specifics of the wake experiences and their relative contribution to experience-dependent modulation of sleep. Honey bees provide an excellent model system in this regard because their behavioral repertoire is well characterized and the environment they experience during the day can be manipulated while keeping an ecologically and sociobiologically relevant context. We examined whether social experience modulates sleep in honey bees, and evaluated the relative contribution of different social signals. We exposed newly emerged bees to different components of their natural social environment and then monitored their sleep behavior in individual cages in a constant lab environment. We found that rich waking experience modulates subsequent sleep. Bees that experienced the colony environment for 1 or 2 days slept more than same-age sister bees that were caged individually or in small groups in the lab. Furthermore, bees placed in mesh-enclosures in the colony, that prevented direct contact with nestmates, slept similarly to bees freely moving in the colony. These results suggest that social signals that do not require direct or close distance interactions between bees are sufficiently rich to encompass almost the entire effect of the colony on sleep. Our findings provide a remarkable example of social experience- dependent modulation of an essential biological process.},
	issn = {0022-0949},
	doi = {10.1242/jeb.110619},
	author = {Eban-Rothschild, Ada and Bloch, Guy}
}
@article {10.3389/fgene.2015.00193,
	title = {Function and evolution of microRNAs in eusocial Hymenoptera},
	journal = {Frontiers in Genetics},
	volume = {6},
	year = {2015},
	pages = {193},
	abstract = {The emergence of eusociality ({\textquotedblleft}true sociality{\textquotedblright}) in several insect lineages represents one of the most successful evolutionary adaptations in the animal kingdom in terms of species richness and global biomass. In contrast to solitary insects, eusocial insects evolved a set of unique behavioral and physiological traits such as reproductive division of labor and cooperative brood care, which likely played a major role in their ecological success. The molecular mechanisms that support the social regulation of behavior in eusocial insects, and their evolution, are mostly unknown. The recent whole-genome sequencing of several eusocial insect species set the stage for deciphering the molecular and genetic bases of eusociality, and the possible evolutionary modifications that led to it. Studies of mRNA expression patterns in the brains of diverse eusocial insect species have indicated that specific social behavioral states of individual workers and queens are often associated with particular tissue-specific transcriptional profiles. Here we discuss recent findings that highlight the role of non-coding microRNAs (miRNAs) in modulating traits associated with reproductive and behavioral divisions of labor in eusocial insects. We provide bioinformatic and phylogenetic data, which suggest that some Hymenoptera-specific miRNA may have contributed to the evolution of traits important for the evolution of eusociality in this group.},
	issn = {1664-8021},
	doi = {10.3389/fgene.2015.00193},
	url = {https://www.frontiersin.org/article/10.3389/fgene.2015.00193},
	author = {S{\o}vik, Eirik and Bloch, Guy and Ben-Shahar, Yehuda}
}
@article { ISI:000353676700001,
	title = {The genomes of two key bumblebee species with primitive eusocial organization},
	journal = {GENOME BIOLOGY},
	volume = {16},
	year = {2015},
	month = {APR 24},
	abstract = {Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation.},
	issn = {1465-6906},
	doi = {10.1186/s13059-015-0623-3},
	author = {Sadd, Ben M. and Barribeau, Seth M. and Bloch, Guy and de Graaf, Dirk C. and Dearden, Peter and Elsik, Christine G. and Gadau, Juergen and Grimmelikhuijzen, Cornelis J. P. and Hasselmann, Martin and Lozier, Jeffrey D. and Robertson, Hugh M. and Smagghe, Guy and Stolle, Eckart and Van Vaerenbergh, Matthias and Waterhouse, Robert M. and Bornberg-Bauer, Erich and Klasberg, Steffen and Bennett, Anna K. and Camara, Francisco and Guigo, Roderic and Hoff, Katharina and Mariotti, Marco and Munoz-Torres, Monica and Murphy, Terence and Santesmasses, Didac and Amdam, Gro V. and Beckers, Matthew and Beye, Martin and Biewer, Matthias and Bitondi, Marcia M. G. and Blaxter, Mark L. and Bourke, Andrew F. G. and Brown, Mark J. F. and Buechel, Severine D. and Cameron, Rossanah and Cappelle, Kaat and Carolan, James C. and Christiaens, Olivier and Ciborowski, Kate L. and Clarke, David F. and Colgan, Thomas J. and Collins, David H. and Cridge, Andrew G. and Dalmay, Tamas and Dreier, Stephanie and du Plessis, Louis and Duncan, Elizabeth and Erler, Silvio and Evans, Jay and Falcon, Tiago and Flores, Kevin and Freitas, Flavia C. P. and Fuchikawa, Taro and Gempe, Tanja and Hartfelder, Klaus and Hauser, Frank and Helbing, Sophie and Humann, Fernanda C. and Irvine, Frano and Jermiin, Lars S. and Johnson, Claire E. and Johnson, Reed M. and Jones, Andrew K. and Kadowaki, Tatsuhiko and Kidner, Jonathan H. and Koch, Vasco and Koehler, Arian and Kraus, F. Bernhard and Lattorff, H. Michael G. and Leask, Megan and Lockett, Gabrielle A. and Mallon, Eamonn B. and Antonio, David S. Marco and Marxer, Monika and Meeus, Ivan and Moritz, Robin F. A. and Nair, Ajay and Napflin, Kathrin and Nissen, Inga and Niu, Jinzhi and Nunes, Francis M. F. and Oakeshott, John G. and Osborne, Amy and Otte, Marianne and Pinheiro, Daniel G. and Rossie, Nina and Rueppell, Olav and Santos, Carolina G. and Schmid-Hempel, Regula and Schmitt, Bjoern D. and Schulte, Christina and Simoes, Zila L. P. and Soares, Michelle P. M. and Swevers, Luc and Winnebeck, Eva C. and Wolschin, Florian and Yu, Na and Zdobnov, Evgeny M. and Aqrawi, Peshtewani K. and Blankenburg, Kerstin P. and Coyle, Marcus and Francisco, Liezl and Hernandez, Alvaro G. and Holder, Michael and Hudson, Matthew E. and Jackson, LaRonda and Jayaseelan, Joy and Joshi, Vandita and Kovar, Christie and Lee, Sandra L. and Mata, Robert and Mathew, Tittu and Newsham, Irene F. and Ngo, Robin and Okwuonu, Geoffrey and Pham, Christopher and Pu, Ling-Ling and Saada, Nehad and Santibanez, Jireh and Simmons, DeNard and Thornton, Rebecca and Venkat, Aarti and Walden, Kimberly K. O. and Wu, Yuan-Qing and Debyser, Griet and Devreese, Bart and Asher, Claire and Blommaert, Julie and Chipman, Ariel D. and Chittka, Lars and Fouks, Bertrand and Liu, Jisheng and O{\textquoteright}Neill, Meaghan P. and Sumner, Seirian and Puiu, Daniela and Qu, Jiaxin and Salzberg, Steven L. and Scherer, Steven E. and Muzny, Donna M. and Richards, Stephen and Robinson, Gene E. and Gibbs, Richard A. and Schmid-Hempel, Paul and Worley, Kim C.}
}
@article { ISI:000369017900006,
	title = {Juvenile hormone and ecdysteroids as major regulators of brain and behavior in bees},
	journal = {CURRENT OPINION IN INSECT SCIENCE},
	volume = {12},
	year = {2015},
	month = {DEC},
	pages = {26-37},
	abstract = {The genome sequencing of several bee species, and the development of functional genomics tools, paved the way for understanding the fascinating behaviors of bees in molecular terms. Here we review recent progress in research on the hormonal regulation of bee behavior, with emphasis on two key insect hormones: Juvenile hormones (JH) and ecdysteroids (Ec). We discuss recent progress in deciphering the molecular bases for JH regulation of gene expression in the nervous system and other tissues. The patterns of JH-dependent changes in gene expression show many similarities across tissues, which are associated with the effects of JH on worker task allocation. Ec, which have previously been studied mainly in the context of insect development, now appear to also play imortant roles in the regulation of many molecular processes in the brain that are asociated with bee behavior. Finally, we discuss the possibility that JH-signaling and Ec-signaling pathways interact to shape the complex behavioral repertoire of bees.},
	issn = {2214-5745},
	doi = {10.1016/j.cois.2015.09.006},
	author = {Pandey, Atul and Bloch, Guy}
}
@article { ISI:000338404900001,
	title = {The expression and phylogenetics of the Inhibitor Cysteine Knot peptide OCLP1 in the honey bee Apis mellifera},
	journal = {JOURNAL OF INSECT PHYSIOLOGY},
	volume = {65},
	year = {2014},
	month = {JUN},
	pages = {1-8},
	abstract = {Small cysteine-rich peptides have diverse functions in insects including antimicrobial defense, phenoloxidase activity regulation, and toxic inhibition of ion channels of prey or predator. We combined bioinformatics and measurements of transcript abundance to start characterizing AmOCLP1, a recently discovered Inhibitor Cysteine Knot peptide in the honey bee Apis mellifera. We found that the genomes of ants, bees, and the wasp Nasonia vitripennis encode orthologous sequences indicating that OCLP1 is a conserved peptide and not unique to the honey bee. Search of available EST libraries and quantitative real time PCR analyses indicate that the transcript of AmOCLP1 is ubiquitous with expression in life stages ranging from embryos to adults and in all tested tissues. In worker honey bees AmOCLP1 expression was not associated with age or task and did not show clear enrichment in any of the tested tissues. There was however a consistent trend toward higher transcript levels in the abdomen of foragers relative to levels in the head or thorax, and compared to levels in the abdomen of younger worker bees. By contrast, in drones AmOCLP1 transcript levels appeared higher in the head relative to the abdomen. Finer analyses of the head and abdomen indicated that the AmOCLP1 transcript is not enriched in the stinger and the associated venom sac or in cephalic exocrine glands. The evolutionary conservation in the Hymenoptera, the ubiquitous expression, and the lack of enrichment in the venom gland, stinger, exocrine glands, and the brain are not consistent with the hypotheses that OCLP1 is a secreted honeybee toxin or an endotoxin acting in the central nervous system. Rather we hypothesize that OCLP1 is a conserved antimicrobial or phenoloxidase inhibitor peptide. (C) 2014 Elsevier Ltd. All rights reserved.},
	issn = {0022-1910},
	doi = {10.1016/j.jinsphys.2014.04.001},
	author = {Bloch, Guy and Cohen, Mira}
}
@article { ISI:000338633900066,
	title = {Gonadotropic and Physiological Functions of Juvenile Hormone in Bumblebee (Bombus terrestris) Workers},
	journal = {PLOS ONE},
	volume = {9},
	year = {2014},
	month = {JUN 24},
	abstract = {The evolution of advanced sociality in bees is associated with apparent modifications in juvenile hormone (JH) signaling. By contrast to most insects in which JH is a gonadotropin regulating female fertility, in the highly eusocial honey bee (Apis mellifera) JH has lost its gonadotrophic function in adult females, and instead regulates age-related division of labor among worker bees. In order to shed light on the evolution of JH signaling in bees we performed allatectomy and replacement therapies to manipulate JH levels in workers of the {\textquoteleft}{\textquoteleft}primitively eusocial{\textquoteright}{\textquoteright} bumblebee Bombus terrestris. Allatectomized worker bees showed remarkable reduction in ovarian development, egg laying, Vitellogenin and Kruppel homolog 1 fat body transcript levels, hemolymph Vitellogenin protein abundance, wax secretion, and egg-cell construction. These effects were reverted, at least partially, by treating allatectomized bees with JH-III, the natural JH of bees. Allatectomy also affected the amount of ester component in Dufour{\textquoteright}s gland secretion, which is thought to convey a social signal relating to worker fertility. These findings provide a strong support for the hypothesis that in contrast to honey bees, JH is a gonadotropin in bumblebees and lend credence to the hypothesis that the evolution of advanced eusociality in honey bees was associated with major modifications in JH signaling.},
	issn = {1932-6203},
	doi = {10.1371/journal.pone.0100650},
	author = {Shpigler, Hagai and Amsalem, Etya and Huang, Zachary Y. and Cohen, Mira and Siegel, Adam J. and Hefetz, Abraham and Bloch, Guy}
}
@article { ISI:000332383100006,
	title = {Molecular heterochrony and the evolution of sociality in bumblebees (Bombus terrestris)},
	journal = {PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES},
	volume = {281},
	year = {2014},
	month = {APR 7},
	abstract = {Sibling care is a hallmark of social insects, but its evolution remains challenging to explain at the molecular level. The hypothesis that sibling care evolved from ancestral maternal care in primitively eusocial insects has been elaborated to involve heterochronic changes in gene expression. This elaboration leads to the prediction that workers in these species will show patterns of gene expression more similar to foundress queens, who express maternal care behaviour, than to established queens engaged solely in reproductive behaviour. We tested this idea in bumblebees (Bombus terrestris) using a microarray platform with approximately 4500 genes. Unlike the wasp Polistes metricus, in which support for the above prediction has been obtained, we found that patterns of brain gene expression in foundress and queen bumblebees were more similar to each other than to workers. Comparisons of differentially expressed genes derived from this study and gene lists from microarray studies in Polistes and the honeybee Apis mellifera yielded a shared set of genes involved in the regulation of related social behaviours across independent eusocial lineages. Together, these results suggest that multiple independent evolutions of eusociality in the insects might have involved different evolutionary routes, but nevertheless involved some similarities at the molecular level.},
	issn = {0962-8452},
	doi = {10.1098/rspb.2013.2419},
	author = {Woodard, S. Hollis and Bloch, Guy M. and Band, Mark R. and Robinson, Gene E.}
}
@article { ISI:000321255700004,
	title = {Animal activity around the clock with no overt circadian rhythms: patterns, mechanisms and adaptive value},
	journal = {PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES},
	volume = {280},
	year = {2013},
	month = {AUG 22},
	abstract = {Circadian rhythms are ubiquitous in many organisms. Animals that are forced to be active around the clock typically show reduced performance, health and survival. Nevertheless, we review evidence of animals showing prolonged intervals of activity with attenuated or nil overt circadian rhythms and no apparent ill effects. We show that around-the-clock and ultradian activity patterns are more common than is generally appreciated, particularly in herbivores, in animals inhabiting polar regions and habitats with constant physical environments, in animals during specific life-history stages (such as migration or reproduction), and in highly social animals. The underlying mechanisms are diverse, but studies suggest that some circadian pacemakers continue to measure time in animals active around the clock. The prevalence of around-the-clock activity in diverse animals and habitats, and an apparent diversity of underlying mechanisms, are consistent with convergent evolution. We suggest that the basic organizational principles of the circadian system and its complexity encompass the potential for chronobiological plasticity. There may be trade-offs between benefits of persistent daily rhythms versus plasticity, which for reasons still poorly understood make overt daily arrhythmicity functionally adaptive only in selected habitats and for selected lifestyles.},
	issn = {0962-8452},
	doi = {10.1098/rspb.2013.0019},
	author = {Bloch, Guy and Barnes, Brian M. and Gerkema, Menno P. and Helm, Barbara}
}
@article { ISI:000321255700028,
	title = {Animal clocks: when science meets nature},
	journal = {PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES},
	volume = {280},
	year = {2013},
	month = {AUG 22},
	abstract = {Daily rhythms of physiology and behaviour are governed by an endogenous timekeeping mechanism (a circadian {\textquoteleft}clock{\textquoteright}), with the alternation of environmental light and darkness synchronizing (entraining) these rhythms to the natural day-night cycle. Our knowledge of the circadian system of animals at the molecular, cellular, tissue and organismal levels is remarkable, and we are beginning to understand how each of these levels contributes to the emergent properties and increased complexity of the system as a whole. For the most part, these analyses have been carried out using model organisms in standard laboratory housing, but to begin to understand the adaptive significance of the clock, we must expand our scope to study diverse animal species from different taxonomic groups, showing diverse activity patterns, in their natural environments. The seven papers in this Special Feature of Proceedings of the Royal Society B take on this challenge, reviewing the influences of moonlight, latitudinal clines, evolutionary history, social interactions, specialized temporal niches, annual variation and recently appreciated post-transcriptional molecular mechanisms. The papers emphasize that the complexity and diversity of the natural world represent a powerful experimental resource.},
	issn = {0962-8452},
	doi = {10.1098/rspb.2013.1354},
	author = {Kronfeld-Schor, Noga and Bloch, Guy and Schwartz, William J.}
}
@article { ISI:000315004500008,
	title = {Circadian rhythms and endocrine functions in adult insects},
	journal = {JOURNAL OF INSECT PHYSIOLOGY},
	volume = {59},
	year = {2013},
	month = {JAN},
	pages = {56-69},
	abstract = {Many behavioral and physiological processes in adult insects are influenced by both the endocrine and circadian systems, suggesting that these two key physiological systems interact. We reviewed the literature and found that experiments explicitly testing these interactions in adult insects have only been conducted for a few species. There is a shortage of measurements of hormone titers throughout the day under constant conditions even for the juvenile hormones (JHs) and ecdysteroids, the best studied insect hormones. Nevertheless, the available measurements of hormone titers coupled with indirect evidence for circadian modulation of hormone biosynthesis rate, and the expression of genes encoding proteins involved in hormone biosynthesis, binding or degradation are consistent with the hypothesis that the circulating levels of many insect hormones are influenced by the circadian system. Whole genome microarray studies suggest that the modulation of farnesol oxidase levels is important for the circadian regulation of JH biosynthesis in honey bees, mosquitoes, and fruit flies. Several studies have begun to address the functional significance of circadian oscillations in endocrine signaling. The best understood system is the circadian regulation of Pheromone Biosynthesis Activating Neuropeptide (PBAN) titers which is important for the temporal organization of sexual behavior in female moths. The evidence that the circadian and endocrine systems interact has important implications for studies of insect physiology and behavior. Additional studies on diverse species and physiological processes are needed for identifying basic principles underlying the interactions between the circadian and endocrine systems in insects. (C) 2012 Elsevier Ltd. All rights reserved.},
	issn = {0022-1910},
	doi = {10.1016/j.jinsphys.2012.10.012},
	author = {Bloch, Guy and Hazan, Esther and Rafaeli, Ada}
}
@article { ISI:000324104500006,
	title = {Social influences on body size and developmental time in the bumblebee Bombus terrestris},
	journal = {BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY},
	volume = {67},
	year = {2013},
	month = {OCT},
	pages = {1601-1612},
	abstract = {In many social insects, including bumblebees, the division of labor between workers relates to body size, but little is known about the factors influencing larval development and final size. We confirmed and extend the evidence that in the bumblebee Bombus terrestris the adult bee body size is positively correlated with colony age. We next performed cross-fostering experiments in which eggs were switched between incipient (before worker emergence) and later stage colonies with workers. The introduced eggs developed into adults similar in size to their unrelated nestmates and not to their same-age full sisters developing in their mother colony. Detailed observations revealed that brood tending by the queen decreases, but does not cease, in young colonies with workers. We next showed that both worker number and the queen presence influenced the final size of the developing brood, but only the queen influence was mediated by shortening developmental time. In colonies separated by a queen excluder, brood developmental time was shorter in the queenright compartment. These findings suggest that differences in body size are regulated by the brood interactions with the queen and workers, and not by factors inside the eggs that could vary along with colony development. Finally, we developed a model showing that the typical increase in worker number and the decrease in brood contact with the queen can account for the typical increase in body size. Similar self-organized social regulation of brood development may contribute to the optimization of growth and reproduction in additional social insects.},
	issn = {0340-5443},
	doi = {10.1007/s00265-013-1571-0},
	author = {Shpigler, Hagai and Tamarkin, Matan and Gruber, Yael and Poleg, Maayan and Siegel, Adam J. and Bloch, Guy}
}
@article { ISI:000323617300016,
	title = {Social regulation of maternal traits in nest-founding bumble bee (Bombus terrestris) queens},
	journal = {JOURNAL OF EXPERIMENTAL BIOLOGY},
	volume = {216},
	year = {2013},
	month = {SEP},
	pages = {3474-3482},
	abstract = {During the nest-founding phase of the bumble bee colony cycle, queens undergo striking changes in maternal care behavior. Early in the founding phase, prior to the emergence of workers in the nest, queens are reproductive and also provision and feed their offspring. However, later in the founding phase, queens reduce their feeding of larvae and become specialized on reproduction. This transition is synchronized with the emergence of workers in the colony, who assume the task of feeding their siblings. Using a social manipulation experiment with the bumble bee Bombus terrestris, we tested the hypothesis that workers regulate the transition from feeding brood to specialization on reproduction in nest-founding bumble bee queens. Consistent with this hypothesis, we found that early-stage nest-founding queens with workers prematurely added to their nests reduce their brood-feeding behavior and increase egg laying, and likewise, late-stage nest-founding queens increase their brood-feeding behavior and decrease egg-laying when workers are removed from their nests. Further, brood-feeding and egg-laying behaviors were negatively correlated. We used Agilent microarrays designed from B. terrestris brain expressed sequenced tags (ESTs) to explore a second hypothesis, that workers alter brain gene expression in nest-founding queens. We found evidence that brain gene expression in nest-founding queens is altered by the presence of workers, with the effect being much stronger in late-stage founding queens. This study provides new insights into how the transition from feeding brood to specialization on reproduction in queen bumble bees is regulated during the nest initiation phase of the colony cycle.},
	issn = {0022-0949},
	doi = {10.1242/jeb.087403},
	author = {Woodard, S. Hollis and Bloch, Guy and Band, Mark R. and Robinson, Gene E.}
}
@article { ISI:000321255700005,
	title = {Socially synchronized circadian oscillators},
	journal = {PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES},
	volume = {280},
	year = {2013},
	month = {AUG 22},
	abstract = {Daily rhythms of physiology and behaviour are governed by an endogenous timekeeping mechanism (a circadian {\textquoteleft}clock{\textquoteright}). The alternation of environmental light and darkness synchronizes (entrains) these rhythms to the natural day-night cycle, and underlying mechanisms have been investigated using singly housed animals in the laboratory. But, most species ordinarily would not live out their lives in such seclusion; in their natural habitats, they interact with other individuals, and some live in colonies with highly developed social structures requiring temporal synchronization. Social cues may thus be critical to the adaptive function of the circadian system, but elucidating their role and the responsible mechanisms has proven elusive. Here, we highlight three model systems that are now being applied to understanding the biology of socially synchronized circadian oscillators: the fruitfly, with its powerful array of molecular genetic tools; the honeybee, with its complex natural society and clear division of labour; and, at a different level of biological organization, the rodent suprachiasmatic nucleus, site of the brain{\textquoteright}s circadian clock, with its network of mutually coupled single-cell oscillators. Analyses at the {\textquoteleft}group{\textquoteright} level of circadian organization will likely generate a more complex, but ultimately more comprehensive, view of clocks and rhythms and their contribution to fitness in nature.},
	issn = {0962-8452},
	doi = {10.1098/rspb.2013.0035},
	author = {Bloch, Guy and Herzog, Erik D. and Levine, Joel D. and Schwartz, William J.}
}
@inbook {Eban-Rothschild2012,
	title = {Circadian Rhythms and Sleep in Honey Bees},
	booktitle = {Honeybee Neurobiology and Behavior: A Tribute to Randolf Menzel},
	year = {2012},
	pages = {31{\textendash}45},
	publisher = {Springer Netherlands},
	organization = {Springer Netherlands},
	address = {Dordrecht},
	isbn = {978-94-007-2099-2},
	doi = {10.1007/978-94-007-2099-2_3},
	url = {http://dx.doi.org/10.1007/978-94-007-2099-2_3},
	author = {Eban-Rothschild, Ada and Bloch, Guy},
	editor = {Galizia, C. Giovanni and Eisenhardt, Dorothea and Giurfa, Martin}
}
@article { ISI:000304715700004,
	title = {The Colony Environment, but Not Direct Contact with Conspecifics, Influences the Development of Circadian Rhythms in Honey Bees},
	journal = {JOURNAL OF BIOLOGICAL RHYTHMS},
	volume = {27},
	year = {2012},
	month = {JUN},
	pages = {217-225},
	abstract = {Honey bee (Apis mellifera) workers emerge from the pupae with no circadian rhythms in behavior or brain clock gene expression but show strong rhythms later in life. This postembryonic development of circadian rhythms is reminiscent of that of infants of humans and other primates but contrasts with most insects, which typically emerge from the pupae with strong circadian rhythms. Very little is known about the internal and external factors regulating the ontogeny of circadian rhythms in bees or in other animals. We tested the hypothesis that the environment during early life influences the later expression of circadian rhythms in locomotor activity in young honey bees. We reared newly emerged bees in various social environments, transferred them to individual cages in constant laboratory conditions, and monitored their locomotor activity. We found that the percentage of rhythmic individuals among bees that experienced the colony environment for their first 48 h of adult life was similar to that of older sister foragers, but their rhythms were weaker. Sister bees isolated individually in the laboratory for the same period were significantly less likely to show circadian rhythms in locomotor activity. Bees experiencing the colony environment for only 24 h, or staying for 48 h with 30 same-age sister bees in the laboratory, were similar to bees individually isolated in the laboratory. By contrast, bees that were caged individually or in groups in single- or double-mesh enclosures inside a field colony were as likely to exhibit circadian rhythms as their sisters that were freely moving in the same colony. These findings suggest that the development of the circadian system in young adult honey bees is faster in the colony than in isolation. Direct contact with the queen, workers, or the brood, contact pheromones, and trophallaxis, which are all important means of communication in honey bees, cannot account for the influence of the colony environment, since they were all withheld from the bees in the double-mesh enclosures. Our results suggest that volatile pheromones, the colony microenvironment, or both influence the ontogeny of circadian rhythms in honey bees.},
	issn = {0748-7304},
	doi = {10.1177/0748730412440851},
	author = {Eban-Rothschild, Ada and Shemesh, Yair and Bloch, Guy}
}
@article { ISI:000303602100062,
	title = {General anesthesia alters time perception by phase shifting the circadian clock},
	journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
	volume = {109},
	year = {2012},
	month = {MAY 1},
	pages = {7061-7066},
	abstract = {Following general anesthesia, people are often confused about the time of day and experience sleep disruption and fatigue. It has been hypothesized that these symptoms may be caused by general anesthesia affecting the circadian clock. The circadian clock is fundamental to our well-being because it regulates almost all aspects of our daily biochemistry, physiology, and behavior. Here, we investigated the effects of the most common general anesthetic, isoflurane, on time perception and the circadian clock using the honeybee (Apis mellifera) as a model. A 6-h daytime anesthetic systematically altered the time-compensated sun compass orientation of the bees, with a mean anticlockwise shift in vanishing bearing of 87 in the Southern Hemisphere and a clockwise shift in flight direction of 58 in the Northern Hemisphere. Using the same 6-h anesthetic treatment, time-trained bees showed a delay in the start of foraging of 3.3 h, and whole-hive locomotor-activity rhythms were delayed by an average of 4.3 h. We show that these effects are all attributable to a phase delay in the core molecular clockwork. mRNA oscillations of the central clock genes cryptochrome-m and period were delayed by 4.9 and 4.3 h, respectively. However, this effect is dependent on the time of day of administration, as is common for clock effects, and nighttime anesthesia did not shift the clock. Taken together, our results suggest that general anesthesia during the day causes a persistent and marked shift of the clock effectively inducing {\textquoteleft}{\textquoteleft}jet lag{\textquoteright}{\textquoteright} and causing impaired time perception. Managing this effect in humans is likely to help expedite postoperative recovery.},
	issn = {0027-8424},
	doi = {10.1073/pnas.1201734109},
	author = {Cheeseman, James F. and Winnebeck, Eva C. and Millar, Craig D. and Kirkland, Lisa S. and Sleigh, James and Goodwin, Mark and Pawley, Matt D. M. and Bloch, Guy and Lehmann, Konstantin and Menzel, Randolf and Warman, Guy R.}
}
@article { ISI:000307154600008,
	title = {The involvement of the antennae in mediating the brood influence on circadian rhythms in {\textquoteleft}{\textquoteleft}nurse{\textquoteright}{\textquoteright} honey bee (Apis mellifera) workers},
	journal = {JOURNAL OF INSECT PHYSIOLOGY},
	volume = {58},
	year = {2012},
	month = {AUG},
	pages = {1096-1103},
	abstract = {Age-related division of labor in honey bees is associated with plasticity in circadian rhythms. Forager bees that are typically older than 3 weeks of age show strong behavioral and molecular circadian rhythms with higher activity during the day. Younger bees that typically care for ({\textquoteright}{\textquoteright}nurse{\textquoteright}{\textquoteright}) the brood are active around the clock with similar brain clock gene levels throughout the day. However, nurses that are caged on brood-less combs inside or outside the hive show robust circadian rhythms with higher activity during the day, suggesting that direct contact with the brood mediates the plasticity in the circadian system. The nature of the brood signals affecting the workers{\textquoteright} circadian system and the modalities by which they are detected are unknown. Given that the antennae are pivotal sensory organs in bees, we hypothesized that they are involved in mediating the brood influence on the plasticity in circadian rhythms. The flagella of the antennae are densely covered with diverse sensory structures able to detect a wide range of signals. To test our hypothesis, we removed the flagella of nurses and observed their behavior in isolation and in free-foraging colonies. We found that individually-isolated flagella-less bees under constant laboratory conditions show robust circadian rhythms in locomotor activity. In observation hives, flagella-less bees cared for the brood, but were more active during the day. By contrast, sham-treated bees were active around the clock as typical of nurses. Detailed video recordings showed that the brood-tending behavior of flagella-less and sham-treated bees is similar. These observations suggest that the difference in the patterns of brood care activity is not because the flagella-less bees did not contact the brood. Our results suggest that nurses are able to find the brood in the dark environment of the hive without their flagella, perhaps by using other sensory organs. The higher activity of flagella-less bees during the day further suggests that the flagella are involved in mediating the brood signals modulating plasticity in the circadian system. (C) 2012 Elsevier Ltd. All rights reserved.},
	issn = {0022-1910},
	doi = {10.1016/j.jinsphys.2012.05.007},
	author = {Nagari, Moshe and Bloch, Guy}
}
@article { ISI:000299848100002,
	title = {Microarray Analysis of Natural Socially Regulated Plasticity in Circadian Rhythms of Honey Bees},
	journal = {JOURNAL OF BIOLOGICAL RHYTHMS},
	volume = {27},
	year = {2012},
	month = {FEB},
	pages = {12-24},
	abstract = {Honey bee workers care for ({\textquoteright}{\textquoteright}nurse{\textquoteright}{\textquoteright}) the brood around the clock without circadian rhythmicity, but then they forage outside with strong circadian rhythms and a consolidated nightly rest. This chronobiological plasticity is associated with variation in the expression of the canonical {\textquoteleft}{\textquoteleft}clock genes{\textquoteright}{\textquoteright} that regulate the circadian clock: nurse bees show no brain rhythms of expression, while foragers do. These results suggest that the circadian system is organized differently in nurses and foragers. Nurses switch to activity with circadian rhythms shortly after being removed from the hive, suggesting that at least some clock cells in their brain continue to measure time while in the hive. We performed a microarray genome-wide survey to determine general patterns of brain gene expression in nurses and foragers sampled around the clock. We found 160 and 541 transcripts that exhibited significant sinusoidal oscillations in nurses and foragers, respectively, with peaks of expression distributed throughout the day in both task groups. Consistent with earlier studies, transcripts of genes involved in circadian rhythms, including Clockwork Orange that has not been studied before in bees, oscillated in foragers but not in nurses. The oscillating transcripts also were enriched for genes involved in the visual system, {\textquoteleft}{\textquoteleft}development{\textquoteright}{\textquoteright} and {\textquoteleft}{\textquoteleft}response to stimuli{\textquoteright}{\textquoteright} (foragers), {\textquoteleft}{\textquoteleft}muscle contraction{\textquoteright}{\textquoteright} and {\textquoteleft}{\textquoteleft}microfilament motor gene expression{\textquoteright}{\textquoteright} (nurses), and {\textquoteleft}{\textquoteleft}generation of precursor metabolites{\textquoteright}{\textquoteright} and {\textquoteleft}{\textquoteleft}energy{\textquoteright}{\textquoteright} (both). Transcripts of genes encoding P450 enzymes oscillated in both nurses and foragers but with a different phase. This study identified new putative clock-controlled genes in the honey bee and suggests that some brain functions show circadian rhythmicity even in nurse bees that are active around the clock.},
	issn = {0748-7304},
	doi = {10.1177/0748730411431404},
	author = {Rodriguez-Zas, Sandra L. and Southey, Bruce R. and Shemesh, Yair and Rubin, Elad B. and Cohen, Mira and Robinson, Gene E. and Bloch, Guy}
}
@article { ISI:000311234600002,
	title = {The Molecular Clockwork of the Fire Ant Solenopsis invicta},
	journal = {PLOS ONE},
	volume = {7},
	year = {2012},
	month = {NOV 13},
	abstract = {The circadian clock is a core molecular mechanism that allows organisms to anticipate daily environmental changes and adapt the timing of behaviors to maximize efficiency. In social insects, the ability to maintain the appropriate temporal order is thought to improve colony efficiency and fitness. We used the newly sequenced fire ant (Solenopsis invicta) genome to characterize the first ant circadian clock. Our results reveal that the fire ant clock is similar to the clock of the honeybee, a social insect with an independent evolutionary origin of sociality. Gene trees for the eight core clock genes, period, cycle, clock, cryptochrome-m, timeout, vrille, par domain protein 1 \& clockwork orange, show ant species grouping closely with honeybees and Nasonia wasps as an outgroup to the social Hymenoptera. Expression patterns for these genes suggest that the ant clock functions similar to the honeybee clock, with period and cry-m mRNA levels increasing during the night and cycle and clockwork orange mRNAs cycling approximately anti-phase to period. Gene models for five of these genes also parallel honeybee models. In particular, the single ant cryptochrome is an ortholog of the mammalian-type (cry-m), rather than Drosophila-like protein (cry-d). Additionally, we find a conserved VPIFAL C-tail region in clockwork orange shared by insects but absent in vertebrates. Overall, our characterization of the ant clock demonstrates that two social insect lineages, ants and bees, share a similar, mammalian-like circadian clock. This study represents the first characterization of clock genes in an ant and is a key step towards understanding socially-regulated plasticity in circadian rhythms by facilitating comparative studies on the organization of circadian clockwork.},
	issn = {1932-6203},
	doi = {10.1371/journal.pone.0045715},
	author = {Ingram, Krista K. and Kutowoi, Alexander and Wurm, Yannick and Shoemaker, DeWayne and Meier, Rudolf and Bloch, Guy}
}
@article { ISI:000303796000003,
	title = {Raalin, a transcript enriched in the honey bee brain, is a remnant of genomic rearrangement in hymenoptera},
	journal = {INSECT MOLECULAR BIOLOGY},
	volume = {21},
	year = {2012},
	month = {JUN},
	pages = {305-318},
	abstract = {We identified a predicted compact cysteine-rich sequence in the honey bee genome that we called Raalin. Raalin transcripts are enriched in the brain of adult honey bee workers and drones, with only minimum expression in other tissues or in pre-adult stages. Open-reading frame (ORF) homologues of Raalin were identified in the transcriptomes of fruit flies, mosquitoes and moths. The Raalin-like gene from Drosophila melanogaster encodes for a short secreted protein that is maximally expressed in the adult brain with negligible expression in other tissues or pre-imaginal stages. Raalin-like sequences have also been found in the recently sequenced genomes of six ant species, but not in the jewel wasp Nasonia vitripennis. As in the honey bee, the Raalin-like sequences of ants do not have an ORF. A comparison of the genome region containing Raalin in the genomes of bees, ants and the wasp provides evolutionary support for an extensive genome rearrangement in this sequence. Our analyses identify a new family of ancient cysteine-rich short sequences in insects in which insertions and genome rearrangements may have disrupted this locus in the branch leading to the Hymenoptera. The regulated expression of this transcript suggests that it has a brain-specific function.},
	issn = {0962-1075},
	doi = {10.1111/j.1365-2583.2012.01138.x},
	author = {Tirosh, Y. and Morpurgo, N. and Cohen, M and Linial, M. and Bloch, G.}
}
@article { ISI:000303796000004,
	title = {Size-related variation in protein abundance in the brain and abdominal tissue of bumble bee workers},
	journal = {INSECT MOLECULAR BIOLOGY},
	volume = {21},
	year = {2012},
	month = {JUN},
	pages = {319-325},
	abstract = {Female bumble bee workers of the same species often show a profound body size variation that is linked to a division of labour. Large individuals are more likely to forage whereas small individuals are more likely to perform in-nest activities. A higher sensory sensitivity, stronger circadian rhythms as well as better learning and memory performances appear to better equip large individuals for outdoor activities compared to their smaller siblings. The molecular mechanisms underlying worker functional polymorphism remain unclear. Proteins are major determinants of an individual{\textquoteright}s morphology and behaviour. We hypothesized that the abundance of proteins such as metabolic enzymes as well as proteins involved in neuronal functions would differ with body size and provide insights into the mechanisms underlying size-dependent physiological specialization in bumble bee workers. We conducted protein quantification measurements based on liquid chromatography coupled with tandem mass spectrometry on tissue samples derived from small and large Bombus impatiens and Bombus terrestris workers. Proteins found to differ significantly in abundance between small and large workers belong to the categories of structure, energy metabolism and stress response. These findings provide the first proteomic insight into mechanisms associated with size-based division of labour in social insects.},
	issn = {0962-1075},
	doi = {10.1111/j.1365-2583.2012.01142.x},
	author = {Wolschin, F. and Shpigler, H. and Amdam, G. V. and Bloch, G.}
}
@inbook { ISI:000310242200001,
	title = {Social Influences on Circadian Rhythms and Sleep in Insects},
	booktitle = {GENE-ENVIRONMENT INTERPLAY},
	series = {Advances in Genetics},
	volume = {77},
	year = {2012},
	pages = {1-32},
	abstract = {The diverse social lifestyle and the small and accessible nervous system of insects make them valuable for research on the adaptive value and the organization principles of circadian rhythms and sleep. We focus on two complementary model insects, the fruit fly Drosophila melanogaster, which is amenable to extensive transgenic manipulations, and the honey bee Apis mellifera, which has rich and well-studied social behaviors. Social entrainment of activity rhythms (social synchronization) has been studied in many animals. Social time givers appear to be specifically important in dark cavity-dwelling social animals, but here there are no other clear relationships between the degree of sociality and the effectiveness of social entrainment. The olfactory system is important for social entrainment in insects. Little is known, however, about the molecular and neuronal pathways linking olfactory neurons to the central clock. In the honey bee, the expression, phase, and development of circadian rhythms are socially regulated, apparently by different signals. Peripheral clocks regulating pheromone synthesis and the olfactory system have been implicated in social influences on circadian rhythms in the fruit fly. An enriched social environment increases the total amount of sleep in both fruit flies and honey bees. In fruit flies, these changes have been linked to molecular and neuronal processes involved in learning, memory, and synaptic plasticity. The studies on insects suggest that social influences on the clock are richer than previously appreciated and have led to important breakthroughs in our understanding of the mechanisms underlying social influences on sleep and circadian rhythms. (C) 2012, Elsevier Inc.},
	isbn = {978-0-12-387687-4},
	issn = {0065-2660},
	doi = {10.1016/B9780-0-12-387687-4.00001-5},
	author = {Eban-Rothschild, Ada and Bloch, Guy},
	editor = {Sokolowski, MB and Goodwin, SF}
}
@article { ISI:000296579800007,
	title = {Maternity-related plasticity in circadian rhythms of bumble-bee queens},
	journal = {PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES},
	volume = {278},
	year = {2011},
	month = {DEC 7},
	pages = {3510-3516},
	abstract = {Unlike most animals studied so far in which the activity with no circadian rhythms is pathological or linked to deteriorating performance, worker bees and ants naturally care for their sibling brood around the clock with no apparent ill effects. Here, we tested whether bumble-bee queens that care alone for their first batch of offspring are also capable of a similar chronobiological plasticity. We monitored locomotor activity of Bombus terrestris queens at various life cycle stages, and queens for which we manipulated the presence of brood or removed the ovaries. We found that gynes typically emerged from the pupae with no circadian rhythms, but after several days showed robust rhythms that were not affected by mating or diapauses. Colony-founding queens with brood showed attenuated circadian rhythms, irrespective of the presence of ovaries. By contrast, queens that lost their brood switched again to activity with strong circadian rhythms. The discovery that circadian rhythms in bumble-bee queens are regulated by the life cycle and the presence of brood suggests that plasticity in the circadian clock of bees is ancient and related to maternal behaviour or physiology, and is not a derived trait that evolved with the evolution of the worker caste.},
	issn = {0962-8452},
	doi = {10.1098/rspb.2011.0579},
	author = {Eban-Rothschild, Ada and Belluci, Selma and Bloch, Guy}
}
@article {12702,
	title = {New Biological Books General Biology Photoperiodism: The Biological Calendar. Edited by Randy J. Nelson, David L. Denlinger, and David E. Somers. Oxford and New York: Oxford University Press. 581},
	journal = {The Quarterly Review of Biology},
	volume = {86},
	number = {1},
	year = {2011},
	author = {Bloch, Guy and Green, Rachel}
}
@article { ISI:000291784000009,
	title = {Social molecular pathways and the evolution of bee societies},
	journal = {PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES},
	volume = {366},
	year = {2011},
	month = {JUL 27},
	pages = {2155-2170},
	abstract = {Bees provide an excellent model with which to study the neuronal and molecular modifications associated with the evolution of sociality because relatively closely related species differ profoundly in social behaviour, from solitary to highly social. The recent development of powerful genomic tools and resources has set the stage for studying the social behaviour of bees in molecular terms. We review {\textquoteleft}ground plan{\textquoteright} and {\textquoteleft}genetic toolkit{\textquoteright} models which hypothesize that discrete pathways or sets of genes that regulate fundamental behavioural and physiological processes in solitary species have been co-opted to regulate complex social behaviours in social species. We further develop these models and propose that these conserved pathways and genes may be incorporated into {\textquoteleft}social pathways{\textquoteright}, which consist of relatively independent modules involved in social signal detection, integration and processing within the nervous and endocrine systems, and subsequent behavioural outputs. Modifications within modules or in their connections result in the evolution of novel behavioural patterns. We describe how the evolution of pheromonal regulation of social pathways may lead to the expression of behaviour under new social contexts, and review plasticity in circadian rhythms as an example for a social pathway with a modular structure.},
	issn = {0962-8436},
	doi = {10.1098/rstb.2010.0346},
	author = {Bloch, Guy and Grozinger, Christina M.}
}
@article { ISI:000279058000018,
	title = {Industrial apiculture in the Jordan valley during Biblical times with Anatolian honeybees},
	journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
	volume = {107},
	year = {2010},
	month = {JUN 22},
	pages = {11240-11244},
	abstract = {Although texts and wall paintings suggest that bees were kept in the Ancient Near East for the production of precious wax and honey, archaeological evidence for beekeeping has never been found. The Biblical term {\textquoteleft}{\textquoteleft}honey{\textquoteright}{\textquoteright} commonly was interpreted as the sweet product of fruits, such as dates and figs. The recent discovery of unfired clay cylinders similar to traditional hives still used in the Near East at the site of Tel Rehov in the Jordan valley in northern Israel suggests that a large-scale apiary was located inside the town, dating to the 10th-early 9th centuries B.C.E. This paper reports the discovery of remains of honeybee workers, drones, pupae, and larvae inside these hives. The exceptional preservation of these remains provides unequivocal identification of the clay cylinders as the most ancient beehives yet found. Morphometric analyses indicate that these bees differ from the local subspecies Apis mellifera syriaca and from all subspecies other than A. m. anatoliaca, which presently resides in parts of Turkey. This finding suggests either that the Western honeybee subspecies distribution has undergone rapid change during the last 3,000 years or that the ancient inhabitants of Tel Rehov imported bees superior to the local bees in terms of their milder temper and improved honey yield.},
	issn = {0027-8424},
	doi = {10.1073/pnas.1003265107},
	author = {Bloch, Guy and Francoy, Tiago M. and Wachtel, Ido and Panitz-Cohen, Nava and Fuchs, Stefan and Mazar, Amihai}
}
@article { ISI:000281798700029,
	title = {Molecular Dynamics and Social Regulation of Context-Dependent Plasticity in the Circadian Clockwork of the Honey Bee},
	journal = {JOURNAL OF NEUROSCIENCE},
	volume = {30},
	year = {2010},
	month = {SEP 15},
	pages = {12517-12525},
	abstract = {The social environment influences the circadian clock of diverse animals, but little is known about the functional significance, the specifics of the social signals, or the dynamics of socially mediated changes in the clock. Honey bees switch between activities with and without circadian rhythms according to their social task. Forager bees have strong circadian rhythms, whereas {\textquoteleft}{\textquoteleft}nurse{\textquoteright}{\textquoteright} bees typically care for the brood around-the-clock with no circadian rhythms in behavior or clock gene expression. Here we show that nurse-age bees that were restricted to a broodless comb inside or outside the hive showed robust behavioral and molecular circadian rhythms. By contrast, young nurses tended brood with no circadian rhythms in behavior or clock gene expression, even under a light-dark illumination regime or when placed with brood-but no queen-in a small cage outside the hive. This behavior is context-dependent because nurses showed circadian rhythms in locomotor activity shortly after removal from the hive, and in clock gene expression after similar to 16 h. These findings suggest that direct interaction with the brood modulates the circadian system of honey bees. The dynamics of rhythm development best fit models positing that at least some pacemakers continue to oscillate and be entrained by the environment in nurses that are active around the clock. These cells set the phase to the clock network when the nurse is removed from the hive. These findings suggest that despite its robustness, the circadian system exhibits profound plasticity, enabling adjustment to rapid changes in the social environment.},
	issn = {0270-6474},
	doi = {10.1523/JNEUROSCI.1490-10.2010},
	author = {Shemesh, Yair and Eban-Rothschild, Ada and Cohen, Mira and Bloch, Guy}
}
@article { ISI:000282251300001,
	title = {The Social Clock of the Honeybee},
	journal = {JOURNAL OF BIOLOGICAL RHYTHMS},
	volume = {25},
	year = {2010},
	month = {OCT},
	pages = {307-317},
	abstract = {The honeybee has long been an important model for studying the interplay between the circadian clock and complex behaviors. This article reviews studies further implicating the circadian clock in complex social behaviors in bees. The article starts by introducing honeybee social behavior and sociality and then briefly summarizes current findings on the molecular biology and neuroanatomy of the circadian system of honeybees that point to molecular similarities to the mammalian clockwork rather than to that of Drosophila. Foraging is a social behavior in honeybees that relies on the circadian clock for timing visits to flowers, time-compensated sun-compass navigation, and dance communication used by foragers to recruit nestmates to rewarding flower patches. The circadian clock is also important for the social organization of honeybee societies. Social factors influence the ontogeny of circadian rhythms and are important for social synchronization of worker activities. Both queen and worker bees switch between activities with and without circadian rhythms. In workers this remarkable plasticity is associated with the division of labor; nurse bees care for the brood around the clock with similar levels of clock gene expression throughout the day, whereas foragers have strong behavioral circadian rhythms with oscillating brain clock gene levels. This plasticity in circadian rhythms is regulated by direct contact with the brood and is context-specific in that nurse bees that are removed from the hive exhibit activity with strong behavioral and molecular rhythms. These studies on the sociochronobiology of honeybees and comparative studies with other social insects suggest that the evolution of sociality has influenced the characteristics of the circadian system in honeybees.},
	issn = {0748-7304},
	doi = {10.1177/0748730410380149},
	author = {Bloch, Guy}
}
@article { ISI:000278369600001,
	title = {The transcription factor Kruppel homolog 1 is linked to hormone mediated social organization in bees},
	journal = {BMC EVOLUTIONARY BIOLOGY},
	volume = {10},
	year = {2010},
	month = {APR 30},
	abstract = {Background: Regulation of worker behavior by dominant queens or workers is a hallmark of insect societies, but the underlying molecular mechanisms and their evolutionary conservation are not well understood. Honey bee and bumble bee colonies consist of a single reproductive queen and facultatively sterile workers. The queens{\textquoteright} influences on the workers are mediated largely via inhibition of juvenile hormone titers, which affect division of labor in honey bees and worker reproduction in bumble bees. Studies in honey bees identified a transcription factor, Kruppel-homolog 1 (Kr-h1), whose expression in worker brains is significantly downregulated in the presence of a queen or queen pheromone and higher in forager bees, making this gene an ideal candidate for examining the evolutionary conservation of socially regulated pathways in Hymenoptera. Results: In contrast to honey bees, bumble bees foragers do not have higher Kr-h1 levels relative to nurses: in one of three colonies levels were similar in nurses and foragers, and in two colonies levels were higher in nurses. Similarly to honey bees, brain Kr-h1 levels were significantly downregulated in the presence versus absence of a queen. Furthermore, in small queenless groups, Kr-h1 levels were downregulated in subordinate workers with undeveloped ovaries relative to dominant individuals with active ovaries. Brain Kr-h1 levels were upregulated by juvenile hormone treatment relative to a vehicle control. Finally, phylogenetic analysis indicates that KR-H1 orthologs are presence across insect orders. Though this protein is highly conserved between honey bees and bumble bees, there are significant differences between orthologs of insects from different orders. Conclusions: Our results suggest that Kr-h1 is associated with juvenile hormone mediated regulation of reproduction in bumble bees. The expression of this transcription factor is inhibited by the queen and associated with endocrine mediated regulation of social organization in two species of bees. Thus, KR-H1 may transcriptionally regulate a conserved genetic module that is part of a pathway that has been co-opted to function in social behavior, and adjusts the behavior of workers to their social environmental context.},
	issn = {1471-2148},
	doi = {10.1186/1471-2148-10-120},
	author = {Shpigler, Hagai and Patch, Harland M. and Cohen, Mira and Fan, Yongliang and Grozinger, Christina M. and Bloch, Guy}
}
@article { ISI:000265961700013,
	title = {Body size-related variation in Pigment Dispersing Factor-immunoreactivity in the brain of the bumblebee Bombus terrestris (Hymenoptera, Apidae)},
	journal = {JOURNAL OF INSECT PHYSIOLOGY},
	volume = {55},
	year = {2009},
	note = {Symposium on Biological Clocks - From Genes to Physiology and Behavior held at the 23rd International Congress of Entomology, Durban, SOUTH AFRICA, JUL 06-12, 2008},
	month = {MAY},
	pages = {479-487},
	abstract = {Large bumblebee (Bombus terrestris) workers typically visit flowers to collect pollen and nectar during the day and rest in the nest at night. Small workers are less likely to forage, but instead stay in the nest and tend brood around the clock. Because Pigment Dispersing Factor (PDF) has been identified as a neuromodulator in the circadian network of insects, we used an antiserum that recognizes this peptide to compare patterns of PDF-immunoreactivity (PDF-ir) in the brains of large and small workers. Our study provides the first description of PDF distribution in the bumblebee brain, and shows a pattern that is overall similar to that of the honey bee,Apis mellifera. The brains of large bumblebee workers contained a slightly but significantly higher number of PDF-ir neurons than did the brains of small sister bees. Body size was positively correlated with area of the PDF-ir somata and negatively correlated with the maximal staining intensity. These results provide a neuronal correlate to the previously reported body size-associated variation in behavioral circadian rhythmicity. These differences in PDF-ir are consistent with the hypothesis that body size-based division of labor in bumblebees is associated with adaptations of the morphology and function of the brain circadian system. (C) 2009 Published by Elsevier Ltd.},
	issn = {0022-1910},
	doi = {10.1016/j.jinsphys.2009.01.016},
	author = {Weiss, Ron and Dov, Avital and Fahrbach, Susan E. and Bloch, Guy}
}
@inbook {12699,
	title = {Chapter 30. Endocrine Influences on the Organization of Insect Societies},
	booktitle = {Hormones, Brain and Behavior},
	volume = {2},
	year = {2009},
	pages = {1027- 1068},
	publisher = {Academic Press; 2009},
	organization = {Academic Press; 2009},
	edition = {2nd},
	address = {San Diego},
	abstract = {Chapter Outline 30.1 Introduction 1028 30.2 Overview of Division of Labor in Insect Societies 1028 30.2.1 Division of Labor for Reproduction 1029 30.2.2 Division of Labor among Workers 1029 30.2.3 Primitive and Advanced Eusociality 1030 30.3 Insect Hormones That Influence Division of Labor 1031 30.4 Division of Labor for Reproduction: Endocrine-Mediated Social Interactions among Adult Colony Members 1032 30.4.1 JH and Primitively Eusocial Insects 1033 30.4.2 JH and Advanced Eusocial Insects 1035 30.4.3 Ecdysteroids and Reproductive Division of Labor 1038 30.4.4 Biogenic Amines and Reproductive Division of Labor 1040 30.5 Division of Labor for Reproduction: Endocrine-Mediated Queen/Worker Determination 1041 30.5.1 Physical Factors 1041 30.5.2 Pheromones 1041 30.5.3 Nutrition 1042 30.5.4 Hormonal Integration 1042 30.5.5 Tissue Responses to Caste-Determining Endocrine Factors 1044 30.6 Division of Labor for Colony Growth and Development: Endocrine Influences on Age-Related Division of Labor among Workers 1044 30.6.1 Other Neuroendocrine and Neuromodulatory Factors That Influence Age-Related Division of Labor in Honeybee Colonies 1047 30.7 Division of Labor for Colony Growth and Development: Endocrine Influences on Worker Size and Subcaste 1049 30.7.1 Physical Factors 1049 30.7.2 Nutrition and Pheromones 1049 30.7.3 Hormonal Integration 1050 30.7.4 Tissue Responses to Worker Caste-Determining Endocrine Factors 1050 30.8 Summary 1051 30.9 Speculation on the Evolution of Division of Labor: A Neuroendocrine Perspective 1051 30.9.1 Level One: Incipient Societies and Endocrine-Mediated Social Inhibition among Adults 1053 30.9.2 Level Two: Pre-Adult, Endocrine-Mediated Social Inhibition 1054 30.9.3 Level Three: Pre-Adult, Endocrine-Mediated Social Inhibition Enhanced by Disruptive Selection 1054 30.9.4 Level Four: Division of Labor among Adult Workers and Its Regulation by Endocrine-Mediated Social Inhibition 1055 30.9.5 Level Five: Division of Labor among Morphologically Distinct Adult Workers and Its Regulation by Pre-Adult, Endocrine-Mediated Social Inhibition 1056 30.9.6 Concluding Remarks 1056 References 1057 Further Reading 1067},
	url = {https://www.researchgate.net/profile/Guy_Bloch/publication/255718572_3_Bloch_G_Shpigler_H_Wheeler_D_E_and_Robinson_G_E_2009_Endocrine_influences_on_the_organization_of_insect_societies_Volume_II_Non-Mammalian_Hormone-Behavior_Systems_Non-Mammalian_Inverte},
	author = {Bloch, Guy and Shpigler, Hagai and DE Wheeler and Robinson, GE},
	editor = {Donald W. Pfaff}
}
@article {12701,
	title = {Plasticity in the circadian clock and the temporal organization of insect societies},
	journal = {Organization of insect societies: from genome to sociocomplexity. Harvard University Press, Cambridge},
	year = {2009},
	pages = {402-432},
	author = {Bloch, G.}
}
@article { ISI:000257620300014,
	title = {Differences in the sleep architecture of forager and young honeybees (Apis mellifera)},
	journal = {JOURNAL OF EXPERIMENTAL BIOLOGY},
	volume = {211},
	year = {2008},
	month = {AUG 1},
	pages = {2408-2416},
	abstract = {Honeybee (Apis mellifera) foragers are among the first invertebrates for which sleep behavior has been described. Foragers (typically older than 21 days) have strong circadian rhythms; they are active during the day, and sleep during the night. We explored whether young bees (similar to 3 days of age), which are typically active around-the-clock with no circadian rhythms, also exhibit sleep behavior. We combined 24-hour video recordings, detailed behavioral observations, and analyses of response thresholds to a light pulse for individually housed bees in various arousal states. We characterized three sleep stages in foragers on the basis of differences in body posture, bout duration, antennae movements and response threshold. Young bees exhibited sleep behavior consisting of the same three stages as observed in foragers. Sleep was interrupted by brief awakenings, which were as frequent in young bees as in foragers. Beyond these similarities, we found differences in the sleep architecture of young bees and foragers. Young bees passed more frequently between the three sleep stages, and stayed longer in the lightest sleep stage than foragers. These differences in sleep architecture may represent developmental and/or environmentally induced variations in the neuronal network underlying sleep in honeybees. To the best of our knowledge, this is the first evidence for plasticity in sleep behavior in insects.},
	issn = {0022-0949},
	doi = {10.1242/jeb.016915},
	author = {Eban-Rothschild, Ada D. and Bloch, Guy}
}
@article { ISI:000254920800009,
	title = {Temporal variation in group aggressiveness of honeybee (Apis mellifera) guards},
	journal = {APIDOLOGIE},
	volume = {39},
	year = {2008},
	month = {MAR-APR},
	pages = {283-291},
	abstract = {Little is known about the temporal organization of defensive behavior in honeybees. We studied {\textquoteleft}{\textquoteleft}guards{\textquoteright}{\textquoteright}, the best-characterized class of colony defenders. We synchronized small groups under a light-dark illumination regime (LD), and video recorded their aggression toward an intruder bumblebee worker. In 1 out of 3 trials (each trial with a different source colony), the latency before the first attack was longer during the night in LD, or subjective night in constant conditions (DD); a similar trend was observed in DD in the two other trials. In 2 out of 3 trials, the number of stinging attempts varied with highest levels during the day in DD, but not in LD. There was a similar trend for the number of biting events. These findings reveal temporal variation in aggression under constant conditions, consistent with the hypothesis that the circadian clock influences guard aggressiveness. Nevertheless, the variability between LD and DD and across colonies calls for additional studies before reaching a definitive conclusion.},
	issn = {0044-8435},
	doi = {10.1051/apido:2008005},
	author = {Troen, Hadassah and Dubrovsky, Irit and Tamir, Ram and Bloch, Guy}
}
@article { ISI:000247707400005,
	title = {Genes encoding putative Takeout/juvenile hormone binding proteins in the honeybee (Apis mellifera) and modulation by age and juvenile hormone of the takeout-like gene GB19811},
	journal = {INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY},
	volume = {37},
	year = {2007},
	month = {JUL},
	pages = {689-701},
	abstract = {We identified and characterized eight genes encoding putative Takeout/juvenile hormone binding proteins (To/JHBP) in the honeybee genome. Phylogenetic analyses revealed nine distinct lineages within this gene family, including those containing Takeout (To) and JHBP for which there are no honeybee homologs. Their diversity and ubiquitous expression suggest that To/JHBP proteins are involved in diverse and important processes in insects. We further characterized the expression of one of these genes, GB19811 that is ubiquitously expressed. GB19811 transcript levels in the abdomen increased, and decreased in the head with worker age. There was no influence of colony environment or brood care behavior on GB19811 expression in young bees. Young bees treated with juvenile hormone (JH) showed a decrease in head GB19811 mRNA levels. This finding is consistent with the premise that JH, for which titers typically increase with age, is involved in age-related modulation of GB19811 expression. In contrast to Drosophila Takeout, the expression of GB19811 did not vary with diurnal or circadian rhythms. Taken together, these findings suggest that GB19811 is not an ortholog of Takeout, and is involved in JH-mediated regulation of adult honeybee worker development. (c) 2007 Elsevier Ltd. All rights reserved.},
	issn = {0965-1748},
	doi = {10.1016/j.ibmb.2007.04.002},
	author = {Hagai, Tzachi and Cohen, Mira and Bloch, Guy}
}
@article { ISI:000243820000004,
	title = {Influences of octopamine and juvenile hormone on locomotor behavior and period gene expression in the honeybee, Apis mellifera},
	journal = {JOURNAL OF COMPARATIVE PHYSIOLOGY A-NEUROETHOLOGY SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY},
	volume = {193},
	year = {2007},
	month = {FEB},
	pages = {181-199},
	abstract = {Octopamine (OA) and juvenile hormone (JH) are implicated in the regulation of age-based division of labor in the honeybee, Apis mellifera. We tested the hypothesis that these two neuroendocrine signals influence task-associated plasticity in circadian and diurnal rhythms, and in brain expression of the clock gene period (per). Treatment with OA, OA antagonist (epinastine), or both, did not affect the age at onset of circadian rhythmicity or the free running period in constant darkness (DD). Young bees orally treated with OA in light-dark (LD) illumination regime for 6 days followed by DD showed reduced alpha (the period between the daily onset and offset of activity) during the first 4 days in LD and the first 4 days in DD. Oral treatment with OA, epinastine, or both, but not manipulations of JH levels, caused increased average daily levels and aberrant patterns of brain per mRNA oscillation in young bees. These results suggest that OA and JH do not influence the development or function of the central pacemaker but rather that OA influences the brain expression of a clock gene and characteristics of locomotor behavior that are not thought to be under direct control of the circadian pacemaker.},
	issn = {0340-7594},
	doi = {10.1007/s00359-006-0179-5},
	author = {Bloch, Guy and Meshi, Avital}
}
@article { ISI:000248334400007,
	title = {Monitoring circadian rhythms of individual honey bees in a social environment reveals social influences on postembryonic ontogeny of activity rhythms},
	journal = {JOURNAL OF BIOLOGICAL RHYTHMS},
	volume = {22},
	year = {2007},
	month = {AUG},
	pages = {343-355},
	abstract = {Social factors constitute an important component of the environment of many animals and have a profound influence on their physiology and behavior. Studies of social influences on circadian rhythms have been hampered by a methodological trade-off: automatic data acquisition systems obtain high-quality data but are effective only for individually isolated animals and therefore compromise by requiring a context that may not be sociobiologically relevant. Human observers can monitor animal activity in complex social environments but are limited in the resolution and quality of data that can be gathered. The authors developed and validated a method for prolonged, automatic, high-quality monitoring of focal honey bees in a relatively complex social environment and with minimal illumination. The method can be adapted for studies on other animals. The authors show that the system provides a reliable estimation of the actual path of a focal bee, only rarely misses its location for > I min, and removes most nonspecific signals from the background. Using this system, the authors provide the first evidence of social influence on the ontogeny of activity rhythms. Young bees that were housed with old foragers show similar to 24-h rhythms in locomotor activity at a younger age and with stronger rhythms than bees housed with a similar number of young bees. By contrast, the maturation of the hypopharyngeal glands was slower in bees housed with foragers, similar to findings in previous studies. The morphology and function of the hypopharyngeal glands vary along with age-based division of labor. Therefore, these findings indicate that social inhibition of task-related maturation was effective in the experimental setup. This study suggests that although the ontogeny of circadian rhythms is typically correlated with the age-based division of labor, their social regulation is different.},
	issn = {0748-7304},
	doi = {10.1177/0748730407301989},
	author = {Meshi, A. and Bloch, G.}
}
@article { ISI:000248454400005,
	title = {Natural plasticity in circadian rhythms is mediated by reorganization in the molecular clockwork in honeybees},
	journal = {FASEB JOURNAL},
	volume = {21},
	year = {2007},
	month = {AUG},
	pages = {2304-2311},
	abstract = {Various animals naturally switch to considerable periods of around-the-clock activity with no apparent ill effects. Such plasticity in overt circadian rhythms might be observed because the clock is masked by the influence of external factors, is uncoupled from behavioral outputs, or results from genuine plasticity in the clock machinery. We studied honeybees in which plasticity in circadian rhythms is socially modulated and associated with the division of labor. We confirm that {\textquoteleft}{\textquoteleft}nurse{\textquoteright}{\textquoteright} bees care for the brood around-the-clock even when experiencing a light: dark illumination regime. However, nurses transferred from the hive to individual cages in constant conditions have robust circadian rhythms in locomotor activity with an onset of activity at the subjective morning. These data indicate that circadian rhythmicity in nurses depends on their environment, and suggest that some clockwork components were entrained even in nurses active around the clock while in the hive. Brain oscillations in transcript abundance for the putative clock genes Period, Cryptochrome-m, Cycle, and Timeout were attenuated or totally suppressed in nurses as compared to behaviorally rhythmic foragers, irrespective of the illumination regime. These findings provide the first support for the hypothesis that natural plasticity in circadian rhythms is associated with reorganization of the internal clock-work.},
	issn = {0892-6638},
	doi = {10.1096/fj.06-8032com},
	author = {Shemesh, Yair and Cohen, Mira and Bloch, Guy}
}
@article { ISI:000236676700012,
	title = {Developmentally determined attenuation in circadian rhythms links chronobiology to social organization in bees},
	journal = {JOURNAL OF EXPERIMENTAL BIOLOGY},
	volume = {209},
	year = {2006},
	month = {MAR 15},
	pages = {1044-1051},
	abstract = {We investigated labor- related plasticity in the circadian clock of the bumblebee Bombus terrestris. Bumblebee workers vary enormously in body size, and we found that size, division of labor, and diurnal rhythms in activity are correlated in B. terrestris colonies. Large workers typically perform foraging activities with strong diurnal rhythms and low activity at night, whereas small bees typically care for ( nurse) brood around the clock with weak or no diurnal rhythms. Under constant laboratory conditions, circadian rhythms in locomotor activity were weaker, less stable, and developed at a later age in small ( nurse- size) bees compared to their larger ( forager- size) sisters. Under a light: dark illumination regime, many small bees, particularly at a young age, were active during the dark phase, fewer small bees developed rhythms, and they did so later compared to large bees. Taken together these findings reveal naturally occurring attenuation or suppression in the circadian clock of small bees that is determined during pre- adult development. This deficiency in clock function, however, does not result in pathology but rather appears to be functionally significant, because it is associated with around- the- clock brood care activity and therefore apparently improves divisions of labor and colony efficiency. This in turn suggests that variation in social biology influences traits of the circadian clock.},
	issn = {0022-0949},
	doi = {10.1242/jeb.02125},
	author = {Yerushalmi, S and Bodenhaimer, S and Bloch, G.}
}
@article { ISI:000241523400044,
	title = {Insights into social insects from the genome of the honeybee Apis mellifera},
	journal = {NATURE},
	volume = {443},
	year = {2006},
	month = {OCT 26},
	pages = {931-949},
	abstract = {Here we report the genome sequence of the honeybee Apis mellifera, a key model for social behaviour and essential to global ecology through pollination. Compared with other sequenced insect genomes, the A. mellifera genome has high A+T and CpG contents, lacks major transposon families, evolves more slowly, and is more similar to vertebrates for circadian rhythm, RNA interference and DNA methylation genes, among others. Furthermore, A. mellifera has fewer genes for innate immunity, detoxification enzymes, cuticle-forming proteins and gustatory receptors, more genes for odorant receptors, and novel genes for nectar and pollen utilization, consistent with its ecology and social organization. Compared to Drosophila, genes in early developmental pathways differ in Apis, whereas similarities exist for functions that differ markedly, such as sex determination, brain function and behaviour. Population genetics suggests a novel African origin for the species A. mellifera and insights into whether Africanized bees spread throughout the New World via hybridization or displacement.},
	issn = {0028-0836},
	doi = {10.1038/nature05260},
	author = {Weinstock, George M. and Robinson, Gene E. and Gibbs, Richard A. and Worley, Kim C. and Evans, Jay D. and Maleszka, Ryszard and Robertson, Hugh M. and Weaver, Daniel B. and Beye, Martin and Bork, Peer and Elsik, Christine G. and Hartfelder, Klaus and Hunt, Greg J. and Zdobnov, Evgeny M. and Amdam, Gro V. and Bitondi, Marcia M. G. and Collins, Anita M. and Cristino, Alexandre S. and Lattorff, H. Michael G. and Lobo, Carlos H. and Moritz, Robin F. A. and Nunes, Francis M. F. and Page, Jr., Robert E. and Simoes, Zila L. P. and Wheeler, Diana and Carninci, Piero and Fukuda, Shiro and Hayashizaki, Yoshihide and Kai, Chikatoshi and Kawai, Jun and Sakazume, Naoko and Sasaki, Daisuke and Tagami, Michihira and Albert, Stefan and Baggerman, Geert and Beggs, Kyle T. and Bloch, Guy and Cazzamali, Giuseppe and Cohen, Mira and Drapeau, Mark David and Eisenhardt, Dorothea and Emore, Christine and Ewing, Michael A. and Fahrbach, Susan E. and Foret, Sylvain and Grimmelikhuijzen, Cornelis J. P. and Hauser, Frank and Hummon, Amanda B. and Huybrechts, Jurgen and Jones, Andrew K. and Kadowaki, Tatsuhiko and Kaplan, Noam and Kucharski, Robert and Leboulle, Gerard and Linial, Michal and Littleton, J. Troy and Mercer, Alison R. and Richmond, Timothy A. and Rodriguez-Zas, Sandra L. and Rubin, Elad B. and Sattelle, David B. and Schlipalius, David and Schoofs, Liliane and Shemesh, Yair and Sweedler, Jonathan V. and Velarde, Rodrigo and Verleyen, Peter and Vierstraete, Evy and Williamson, Michael R. and Ament, Seth A. and Brown, Susan J. and Corona, Miguel and Dearden, Peter K. and Dunn, W. Augustine and Elekonich, Michelle M. and Fujiyuki, Tomoko and Gattermeier, Irene and Gempe, Tanja and Hasselmann, Martin and Kadowaki, Tatsuhiko and Kage, Eriko and Kamikouchi, Azusa and Kubo, Takeo and Kucharski, Robert and Kunieda, Takekazu and Lorenzen, Marce D. and Milshina, Natalia V. and Morioka, Mizue and Ohashi, Kazuaki and Overbeek, Ross and Ross, Christian A. and Schioett, Morten and Shippy, Teresa and Takeuchi, Hideaki and Toth, Amy L. and Willis, Judith H. and Wilson, Megan J. and Gordon, Karl H. J. and Letunic, Ivica and Hackett, Kevin and Peterson, Jane and Felsenfeld, Adam and Guyer, Mark and Solignac, Michel and Agarwala, Richa and Cornuet, Jean Marie and Monnerot, Monique and Mougel, Florence and Reese, Justin T. and Vautrin, Dominique and Gillespie, Joseph J. and Cannone, Jamie J. and Gutell, Robin R. and Johnston, J. Spencer and Eisen, Michael B. and Iyer, Venky N. and Iyer, Vivek and Kosarev, Peter and Mackey, Aaron J. and Solovyev, Victor and Souvorov, Alexandre and Aronstein, Katherine A. and Bilikova, Katarina and Chen, Yan Ping and Clark, Andrew G. and Decanini, Laura I. and Gelbart, William M and Hetru, Charles and Hultmark, Dan and Imler, Jean-Luc and Jiang, Haobo and Kanost, Michael and Kimura, Kiyoshi and Lazzaro, Brian P. and Lopez, Dawn L. and Simuth, Jozef and Thompson, Graham J. and Zou, Zhen and De Jong, Pieter and Sodergren, Erica and Csuroes, Miklos and Milosavljevic, Aleksandar and Osoegawa, Kazutoyo and Richards, Stephen and Shu, Chung-Li and Duret, Laurent and Elhaik, Eran and Graur, Dan and Anzola, Juan M. and Campbell, Kathryn S. and Childs, Kevin L. and Collinge, Derek and Crosby, Madeline A. and Dickens, C. Michael and Grametes, L. Sian and Grozinger, Christina M. and Jones, Peter L. and Jorda, Mireia and Ling, Xu and Matthews, Beverly B. and Miller, Jonathan and Mizzen, Craig and Peinado, Miguel A. and Reid, Jeffrey G. and Russo, Susan M. and Schroeder, Andrew J. and St Pierre, Susan E. and Wang, Ying and Zhou, Pinglei and Jiang, Huaiyang and Kitts, Paul and Ruef, Barbara and Venkatraman, Anand and Zhang, Lan and Aquino-Perez, Gildardo and Whitfield, Charles W. and Behura, Susanta K. and Berlocher, Stewart H. and Sheppard, Walter S. and Smith, Deborah R. and Suarez, Andrew V. and Tsutsui, Neil D. and Wei, Xuehong and Wheeler, David and Havlak, Paul and Li, Bingshan and Liu, Yue and Sodergren, Erica and Jolivet, Angela and Lee, Sandra and Nazareth, Lynne V. and Pu, Ling-Ling and Thorn, Rachel and Stolc, Viktor and Newman, Thomas and Samanta, Manoj and Tongprasit, Waraporn A. and Claudianos, Charles and Berenbaum, May R. and Biswas, Sunita and de Graaf, Dirk C. and Feyereisen, Rene and Johnson, Reed M. and Oakeshott, John G. and Ranson, Hilary and Schuler, Mary A. and Muzny, Donna and Chacko, Joseph and Davis, Clay and Dinh, Huyen and Gill, Rachel and Hernandez, Judith and Hines, Sandra and Hume, Jennifer and Jackson, LaRonda and Kovar, Christie and Lewis, Lora and Miner, George and Morgan, Margaret and Nguyen, Ngoc and Okwuonu, Geoffrey and Paul, Heidi and Santibanez, Jireh and Savery, Glenford and Svatek, Amanda and Villasana, Donna and Wright, Rita and Honeybee Genome Sequencing Consort}
}
@article { ISI:000241702700005,
	title = {Molecular and phylogenetic analyses reveal mammalian-like clockwork in the honey bee (Apis mellifera) and shed new light on the molecular evolution of the circadian clock},
	journal = {GENOME RESEARCH},
	volume = {16},
	year = {2006},
	month = {NOV},
	pages = {1352-1365},
	abstract = {The circadian clock of the honey bee is implicated in ecologically relevant complex behaviors. These include time sensing, time-compensated sun-compass navigation, and social behaviors such as coordination of activity, dance language communication, and division of labor. The molecular underpinnings of the bee circadian clock are largely unknown. We show that clock gene structure and expression pattern in the honey bee are more similar to the mouse than to Drosophila. The honey bee genome does not encode an ortholog of Drosophila Timeless (Tim1), has only the mammalian type Cryptochrome (Cry-m), and has a single ortholog for each of the other canonical {\textquoteleft}{\textquoteleft}clock genes.{\textquoteright}{\textquoteright} In foragers that typically have strong circadian rhythms, brain mRNA levels of amCry, but not amTim as in Drosophila, consistently oscillate with strong amplitude and a phase similar to amPeriod (amPer) under both light-dark and constant darkness illumination regimes. In contrast to Drosophila, the honey bee amCYC protein contains a transactivation domain and its brain transcript levels oscillate at virtually an anti-phase to amPer, as it does in the mouse. Phylogenetic analyses indicate that the basal insect lineage had both the mammalian and Drosophila types of Cry and Tim. Our results suggest that during evolution, Drosophila diverged from the ancestral insect clock and specialized in using a set of clock gene orthologs that was lost by both mammals and bees, which in turn converged and specialized in the other set. These findings illustrate a previously unappreciated diversity of insect clockwork and raise critical questions concerning the evolution and functional significance of species-specific variation in molecular clockwork.},
	issn = {1088-9051},
	doi = {10.1101/gr.5094806},
	author = {Rubin, Elad B. and Shemesh, Yair and Cohen, Mira and Elgavish, Sharona and Robertson, Hugh M. and Bloch, Guy}
}
@article { ISI:000235635500017,
	title = {Seasonal and task-related variation in free running activity rhythms in honey bees (Apis mellifera)},
	journal = {INSECTES SOCIAUX},
	volume = {53},
	year = {2006},
	month = {FEB},
	pages = {115-118},
	abstract = {We measured seasonal variation in the locomotor behavior of newly emerged adult honey bee workers in the laboratory. Analyses of bees from 12 colonies, 7 of which were tested once and 5 tested more than once, revealed seasonal changes in the free-running period (FRP) of the rhythm for locomotor behavior, with an increase from spring to summer. At the same time there was a decrease in the age at onset of circadian rhythmicity. There were no seasonal changes in overall levels of locomotor activity. Temperature and photoperiod, the only factors known to mediate plasticity in the insect clock, cannot account for the observed seasonal variation because bees were maintained under constant conditions. In a second experiment we found no differences in the FRP of nurses and foragers obtained from colonies maintained in a 12 h light: 12 h dark illumination regime. These findings suggest that exposure to unknown cues during preadult stages may affect the circadian behavior of adult bees.},
	issn = {0020-1812},
	doi = {10.1007/s00040-005-0844-7},
	author = {Bloch, G. and Shemesh, Y and Robinson, GE}
}
@article { ISI:000231717400008,
	title = {Reproductive division of labor, dominance, and ecdysteroid levels in hemolymph and ovary of the bumble bee Bombus terrestris},
	journal = {JOURNAL OF INSECT PHYSIOLOGY},
	volume = {51},
	year = {2005},
	month = {JUL},
	pages = {811-823},
	abstract = {To determine whether ecdysteroids are associated with reproductive division of labor in Bombus terrestris, we measured their levels in hemolymph and ovaries of queens and workers. Queens heading colonies had large active ovaries with high ecdysteroid content, whereas virgin gynes and mated queens before and after diapause had undeveloped ovaries with low ecdysteroid content. The hemolymph ecdysteroid titer was rather variable, but in a pooled analysis of mated queens before and after diapause versus colony-heading queens, ecdysteroid titers were higher in the latter group. In workers, agonistic behavior, ovarian activity, ovarian ecdysteroid content, and hemolymph ecdysteroid titers were positively correlated, and were lowest when a queen was present. In queenless workers, ecdysteroid levels were elevated in dominant workers, and were also influenced by the presence of brood and by group demography; hormone levels were higher in bees kept in larger groups. These findings are consistent with the premise that in B. terrestris the ovary is the primary site of ecdysteroid synthesis, and they show that ecdysteroids levels vary with the social environment. (c) 2005 Elsevier Ltd. All rights reserved.},
	issn = {0022-1910},
	doi = {10.1016/j.jinsphys.2005.03.009},
	author = {Geva, S and Hartfelder, K and Bloch, G.}
}
@article { ISI:000224001200001,
	title = {period expression in the honey bee brain is developmentally regulated and not affected by light, flight experience, or colony type},
	journal = {INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY},
	volume = {34},
	year = {2004},
	month = {SEP},
	pages = {879-891},
	abstract = {Changes in circadian rhythms of behavior are related to age-based division of labor in honey bee colonies. The expression of the clock gene period (per) in the bee brain is associated with age-related changes in circadian rhythms of behavior, but previous efforts to firmly associate per brain expression with division of labor or age have produced variable results. We explored whether this variability was due to differences in light and flight experience, which vary with division of labor, or differences in colony environment, which are known to affect honey bee behavioral development. Our results support the hypothesis that per mRNA expression in the bee brain is developmentally regulated. One-day-old bees had the lowest levels of expression and rarely showed evidence of diurnal fluctuation, while foragers and forager-age bees (>21 days of age) always had high levels of brain per and strong and consistent diurnal patterns. Results from laboratory and field experiments do not support the hypothesis that light, flight experience, and colony type influence per expression. Our results suggest that the rate of developmental elevation in per expression is influenced by factors other than the ones studied in our experiments, and that young bees are more sensitive to these factors than foragers. (C) 2004 Elsevier Ltd. All rights reserved.},
	issn = {0965-1748},
	doi = {10.1016/j.ibmb.2004.05.004},
	author = {Bloch, G. and Rubinstein, CD and Robinson, GE}
}
@article { ISI:000184776400002,
	title = {Patterns of PERIOD and pigment-dispersing hormone immunoreactivity in the brain of the European honeybee (Apis mellifera): Age- and time-related plasticity},
	journal = {JOURNAL OF COMPARATIVE NEUROLOGY},
	volume = {464},
	year = {2003},
	month = {SEP 22},
	pages = {269-284},
	abstract = {We explored the neural basis of age- and task-related plasticity in circadian patterns of activity in the honeybee. To identify putative circadian pacemakers in the bee brain, we used antibodies against Drosophila melanogaster and Antheraea pernyi PERIOD and an antiserum to crustacean pigment-dispersing hormone (PDH) known to cross-react with insect pigment-dispersing factors (PDFs). In contrast to previous results from Drosophila, PDH and PER immunoreactivity (-ir) were not colocalized in bee neurons. The most intense PER-ir was cytoplasmic, in two groups of large neurons in the protocerebrum. The number of protocerebral PER-ir neurons and PER-ir intensity within individual cells were highest in brains collected during subjective night and higher in old bees than in young bees. These results are consistent with previous analyses of brain per mRNA in honeybees. Nuclear PER-ir was found throughout the brain, including the optic and antennal lobes. A single group of PDH-ir neurons (approximately 20/optic lobe) was consistently and intensely labeled at the medial margin of the medulla, independent of age or time of day. The processes of these neurons extended to specific neuropils in the protocerebrum and the optic lobes but not to the deutocerebrum. The patterns displayed by PER- and PDH-ir do not completely match any patterns previously described. This suggests that, although clock proteins are conserved across insect groups, there is no universal pattern of coexpression that allows ready identification of pacemaker neurons within the insect brain. J. Comp. Neurol. (C) 2003 Wiley-Liss, Inc.},
	issn = {0021-9967},
	doi = {10.1002/cne.10778},
	author = {Bloch, G. and Solomon, SM and Robinson, GE and Fahrbach, SE}
}
@inbook {BLOCH2002195,
	title = {40 - Endocrine Influences on the Organization of Insect Societies},
	booktitle = {Hormones, Brain and Behavior},
	year = {2002},
	pages = {195-235},
	publisher = {Academic Press},
	organization = {Academic Press},
	address = {San Diego},
	abstract = {Publisher Summary This chapter reviews the evidence for endocrine influences on division of labor in insect societies. Juvenile hormone (JH) has been studied most extensively. The influence of JH is widespread. It is involved in the control of four major forms of division of labor: division of labor for reproduction among adults, division of labor for reproduction via caste differentiation, division of labor for colony growth and development among adults, and division of labor for colony growth and development via adult physical castes. These controls involve both pre-adult developmental processes of caste determination, and processes of physiological and behavioral maturation in adults. Studies on ecdysteroids and biogenic amines in these contexts have been started. Ecdysteroids are implicated in the control of caste determination and reproductive maturation in bees. The biogenic amine, octopamine, influences the division of labor among workers; octopamine and serotonin exert neurohormonal influences on the production of JH by the corpora allata in both larval and adult honey bees; and octopamine and dopamine are correlated suggestively with aspects of reproductive development in both bumble bees and honey bees.},
	isbn = {978-0-12-532104-4},
	doi = {https://doi.org/10.1016/B978-012532104-4/50042-1},
	url = {https://www.sciencedirect.com/science/article/pii/B9780125321044500421},
	author = {Bloch, Guy and Diana E. Wheeler and Robinson, Gene E.},
	editor = {Donald W. Pfaff and Arthur P. Arnold and Susan E. Fahrbach and Anne M. Etgen and Robert T. Rubin}
}
@article { ISI:000179662400006,
	title = {Juvenile hormone and circadian locomotor activity in the honey bee Apis mellifera},
	journal = {JOURNAL OF INSECT PHYSIOLOGY},
	volume = {48},
	year = {2002},
	month = {DEC},
	pages = {1123-1131},
	abstract = {Age-related division of labor in honeybees is associated with plasticity in circadian rhythms. Young nest bees care for brood around the clock with no circadian rhythms while older foragers have strong circadian rhythms that are used for sun compass navigation and for timing visits to flowers. Since juvenile hormone (JH) is involved in the coordination of physiological and behavioral processes underlying age-related division of labor in honey bees, we tested the hypothesis that JH influences the ontogeny of circadian rhythms and other clock parameters in young worker bees. Treatments with the JH analog methoprene or allatectomy did not influence the onset of rhythmicity, overall locomotor activity, or the free-running period of rhythmic locomotor behavior. There were, however, significant differences in the onset of rhythmicity, overall locomotor activity, and longevity between bees from different source colonies, suggesting that there is significant genetic variation for these traits. Our results suggest that JH does not coordinate all aspects of division of labor in bees and that coordination of task performance with circadian rhythms is probably mediated by other regulatory systems. (C) 2002 Elsevier Science Ltd. All rights reserved.},
	issn = {0022-1910},
	doi = {10.1016/S0022-1910(02)00205-6},
	author = {Bloch, G. and Sullivan, JP and Robinson, GE}
}
@article { ISI:000171904300003,
	title = {Behavioral rhythmicity, age, division of labor and period expression in the honey bee brain},
	journal = {JOURNAL OF BIOLOGICAL RHYTHMS},
	volume = {16},
	year = {2001},
	month = {OCT},
	pages = {444-456},
	abstract = {Young adult honey bees work inside the beehive {\textquoteleft}{\textquoteleft}nursing{\textquoteright}{\textquoteright} brood around the clock with no circadian rhythms; older bees forage for nectar and pollen outside with strong circadian rhythms. Previous research has shown that the development of an endogenous rhythm of activity is also seen in the laboratory in a constant environment. Newly emerging bees maintained in isolation are typically arrhythmic during the first few days of adult life and develop strong circadian rhythms by about a few days of age. In addition, average daily levels of period (per) mRNA in the brain are higher in foragers or forager-age bees (> 21 days of age) relative to young nest bees (similar to 7 days of age). The authors used social manipulations to uncouple behavioral rhythmicity, age, and task to determine the relationship between these factors and per. There was no obligate link between average daily levels of per brain mRNA and either behavioral rhythmicity or age. There also were no differences in per brain mRNA levels between nurse bees and foragers in social environments that promote precocious or reversed behavioral development. Nurses and other hive-age bees can have high or low levels of per mRNA levels in the brain, depending on the social environment, while foragers and foraging-age bees always have high levels. These findings suggest a link between honey bee foraging behavior and per up-regulation. Results also suggest task-related differences in the amplitude of per mRNA oscillation in the brain, with foragers having larger diurnal fluctuation in per than nurses, regardless of age. Taken together, these results suggest that social factors may exert potent influences on the regulation of clock genes.},
	issn = {0748-7304},
	doi = {10.1177/074873001129002123},
	author = {Bloch, G. and Toma, DP and Robinson, GE}
}
@article { ISI:000168285500036,
	title = {Chronobiology - Reversal of honeybee behavioural rhythms},
	journal = {NATURE},
	volume = {410},
	year = {2001},
	month = {APR 26},
	pages = {1048},
	issn = {0028-0836},
	doi = {10.1038/35074183},
	author = {Bloch, G. and Robinson, GE}
}
@article { ISI:000170925500003,
	title = {Juvenile hormone levels in honey bee (Apis mellifera L.) foragers: foraging experience and diurnal variation},
	journal = {JOURNAL OF INSECT PHYSIOLOGY},
	volume = {47},
	year = {2001},
	month = {SEP},
	pages = {1119-1125},
	abstract = {A rising blood titer of juvenile hormone (JH) in adult worker honey bees is associated with the shift from working in the hive to foraging. We determined whether the JH increase occurs in anticipation of foraging or whether it is a result of actual foraging experience and/or diurnal changes in exposure to sunlight. We recorded all foraging flights of tagged bees observed at a feeder in a large outdoor flight cage. We measured JH from bees that had taken 1, 3-5, or > 100 foraging flights and foragers of indeterminate experience leaving or entering the hive. To study diurnal variation in JH, we sampled foragers every 6 h over one day. Titers of JH in foragers were high relative to nurses as in previous studies, suggesting that conditions in the flight cage had no effect on the relationship between foraging behavior and JH. Titers of JH in foragers showed no significant effects of foraging experience, but did show significant diurnal variation. Our results indicate that the high titer of JH in foragers anticipates the onset of foraging and is not affected by foraging experience, but is modulated diurnally. (C) 2001 Elsevier Science Ltd. All rights reserved.},
	issn = {0022-1910},
	author = {Elekonich, MM and Schulz, DJ and Bloch, G. and Robinson, GE}
}
@article { ISI:000088642300006,
	title = {Brain biogenic amines and reproductive dominance in bumble bees (Bombus terrestris)},
	journal = {JOURNAL OF COMPARATIVE PHYSIOLOGY A-SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY},
	volume = {186},
	year = {2000},
	month = {MAR},
	pages = {261-268},
	abstract = {To begin to explore the role of biogenic amines in reproductive division of labor in social insects, brain levels of dopamine, serotonin, and octopamine were measured in bumble bee (Bombus terrestris) workers and queens that differ in behavioral and reproductive state. Levels of all three amines were similar for mated and virgin queens. Young workers that developed with or without a queen had similar amine levels, but in queenright colonies differences in biogenic amine levels were associated with differences in behavior and reproductive physiology. Dominant workers had significantly higher octopamine levels compared with workers of lower dominance status but of similar size, age, and ovary state. High dopamine levels were associated with the last stages of oocyte development irrespective of worker social status and behavior. These results suggest that biogenic amines are involved in behavioral and physiological aspects of regulation of reproduction in bumble bees.},
	issn = {0340-7594},
	doi = {10.1007/s003590050426},
	author = {Bloch, G. and Simon, T and Robinson, GE and Hefetz, A}
}
@article { ISI:000087526300121,
	title = {Changes in period mRNA levels in the brain and division of labor in honey bee colonies},
	journal = {PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA},
	volume = {97},
	year = {2000},
	month = {JUN 6},
	pages = {6914-6919},
	abstract = {Previous research showed that age-related division of labor in honey bees is associated with changes in activity rhythms; young adult bees perform hive tasks with no daily rhythms, whereas older bees forage with strong daily rhythms. We report that this division of labor is also associated with differences in both circadian rhythms and mRNA levels of period, a gene well known for its role in circadian rhythms. The level of period mRNA in the brain oscillated in bees of all ages, but was significantly higher at all times in foragers, Elevated period mRNA levels cannot be attributed exclusively to aging, because bees induced to forage precociously because of a change in social environment had levels similar to normal age foragers, These results extend the regulation of a {\textquoteleft}{\textquoteleft}clock gene{\textquoteright}{\textquoteright} to a social context and suggest that there are connections at the molecular level between division of labor and chronobiology in social insects.},
	issn = {0027-8424},
	doi = {10.1073/pnas.97.12.6914},
	author = {Toma, DP and Bloch, G. and Moore, D and Robinson, GE}
}
@article { ISI:000087110100022,
	title = {Ecdysteroid titer, ovary status, and dominance in adult worker and queen bumble bees (Bombus terrestris)},
	journal = {JOURNAL OF INSECT PHYSIOLOGY},
	volume = {46},
	year = {2000},
	month = {JUN},
	pages = {1033-1040},
	abstract = {The role of ecdysteroids in the regulation of dominance and reproduction in social Hymenoptera is little explored. In the current study we compared ecdysteroid titers in hemolymph of individual queen and worker bumble bees (Bombus terrestris) that differ in their behavior, reproductive status and social environment. Egg-laying queens that head colonies and have ovaries exhibiting all stages of follicle development, had a higher ecdysteroid titer than virgin queens whose ovaries contained only follicles at initial stages. In workers, the relationship between ecdysteroid titers and follicle development appears to be more complex and to be influenced by the bee{\textquoteright}s social status and social environment. Shortly after emergence, young workers had only follicles at the initial stages of oogenesis and they exhibited a low ecdysteroid titer. No significant, correlation was detected between ovary status and ecdysteroid titer in workers, with some workers showing activated ovaries but low ecdysteroid titers. However, at six days of age, a trend towards higher ecdysteroid titer was observed for workers in queenless groups, a condition characterized by rapid follicle development relative to queenright conditions. In these queenless groups, high social status was associated with high ecdysteroid titers. By contrast, in queenright workers ecdysteroid titers were low, even for bees with presumably high social status that had activated ovaries and were observed performing oviposition behavior. This study suggests that ecdysteroids are involved in regulation of reproduction in B. terrestris. (C) 2000 Elsevier Science Ltd. All rights reserved.},
	issn = {0022-1910},
	doi = {10.1016/S0022-1910(99)00214-0},
	author = {Bloch, G. and Hefetz, A and Hartfelder, K}
}
@article { ISI:000087073500007,
	title = {The effect of queen-worker conflict on caste determination in the bumblebee Bombus terrestris},
	journal = {BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY},
	volume = {47},
	year = {2000},
	month = {APR},
	pages = {346-352},
	abstract = {Endocrine analyses were used to investigate the well-known association between queen production and the onset of worker reproduction (termed the competition phase, CPh) in Bombus terrestris. Larvae that reached the age of 5 days before the CPh had a worker-like profile: low juvenile hormone (JH) biosynthesis rates and low JH hemolymph titers. In contrast, larvae that reached the age of 5 days during the CPh had a queen-like profile: high JH biosynthesis rates and high hemolymph JH levels. Larval fate could be manipulated by transplanting egg cells into host colonies with different social structures. There was a steep rise in JH production in larvae transplanted into colonies near or during the CPh. This indicates that during colony development, larvae switch from the {\textquoteleft}{\textquoteleft}worker developmental pathway{\textquoteright}{\textquoteright} to the {\textquoteleft}{\textquoteleft}queen developmental pathway,{\textquoteright}{\textquoteright} and that the switch is socially regulated. In small rearing groups, larvae reared with queens before the CPh developed into workers, whereas those reared with queens after the CPh developed into queens. Variation in worker type (naive or experienced) did not affect caste determination. Therefore, we hypothesize that queens produce a pheromone that directly inhibits queen differentiation by larvae. We also present two alternative scenarios that explain the timing of gyne production in B. terrestris, one based on ecological constraints and the other based on queen-worker competition.},
	issn = {0340-5443},
	doi = {10.1007/s002650050675},
	author = {Cnaani, J and Robinson, GE and Bloch, G. and Borst, D and Hefetz, A}
}
@article { ISI:000083355700006,
	title = {Juvenile hormone titers, juvenile hormone biosynthesis, ovarian development and social environment in Bombus terrestris},
	journal = {JOURNAL OF INSECT PHYSIOLOGY},
	volume = {46},
	year = {2000},
	month = {JAN},
	pages = {47-57},
	abstract = {The effects of the social environment and age on juvenile hormone (JH) and reproduction were investigated by measuring ovarian development, hemolymph levels of JH III, and rates of JH biosynthesis from the same individual bumble bees (Bombus terrestris). Differences in social environment were associated with differences in rates of JH biosynthesis, JH titer and ovarian development. Young queenless workers had a higher rate of JH biosynthesis, JH titer and ovarian development than queenright (QR) workers of similar age. Dominant workers in QR colonies had a higher rate of JH biosynthesis, JH titer and ovarian development than low ranked workers of similar size. There was a positive correlation between JH titer and ovarian development, but no correlation between rate of JH biosynthesis and ovarian development or between JH biosynthesis and JH titer. Both JH titer and rate of JH biosynthesis increased with age from emergence to 3 days of age, but 6-day-old workers, egg-laying workers, and actively reproducing queens had high JH titers and highly developed ovaries but low rates of JH biosynthesis. These results show that reproduction in B. terrestris is strongly affected by the social environment and the influence of the environment on reproduction is mediated by JH. Our data also indicate that the rate of JH biosynthesis measured in vitro is not a reliable indicator of JH titer or ovarian development in B. terrestris; possible reasons are discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.},
	issn = {0022-1910},
	doi = {10.1016/S0022-1910(99)00101-8},
	author = {Bloch, G. and Borst, DW and Huang, ZY and Robinson, GE and Cnaani, J and Hefetz, A}
}
@article { ISI:000080123000016,
	title = {Reevaluation of the role of mandibular glands in regulation of reproduction in bumblebee colonies},
	journal = {JOURNAL OF CHEMICAL ECOLOGY},
	volume = {25},
	year = {1999},
	month = {APR},
	pages = {881-896},
	abstract = {Possible pheromonal control of worker reproduction was tested in Bombus terrestris. The mode of assay included exposure of callow workers to extracts originating from different queen parts and measuring the effect on the in vitro biosynthesis of juvenile hormone (JH), the apparent gonadotropin in this species. Both queen total body extracts applied to dummies consisting of oven-dried or Soxhlet-washed virgin queen bodies and cuticular washes applied to living virgin queens effectively inhibited the biosynthesis of JH in callow workers. None of the five exocrine glands (mandibular, hypopharyngeal, salivary, Dufour{\textquoteright}s, and tarsal) demonstrated inhibitory activity. Likewise, the use of synthetic 3-hydroxy acids, found in queen mandibular glands, were ineffective in blocking JH biosynthesis in queenless workers. The results suggest that the queen may use a primer pheromone spread on me epicuticle as a means to inhibit worker reproduction. However, our results are not consistent with the prevailing hypothesis that in B. terrestris the main source of the pheromone that inhibits worker reproduction is in the queen{\textquoteright}s mandibular glands.},
	issn = {0098-0331},
	doi = {10.1023/A:1020805103379},
	author = {Bloch, G. and Hefetz, A}
}
@article { ISI:000084682200003,
	title = {Regulation of queen-worker conflict in bumble-bee (Bombus terrestris) colonies},
	journal = {PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES},
	volume = {266},
	year = {1999},
	month = {DEC 22},
	pages = {2465-2469},
	abstract = {In annual colonies of bumble-bees overt queen-worker conflict is limited to a distinct {\textquoteleft}competition phase{\textquoteright} (CPh). In unmanipulated Bombus terrestris colonies, the queen{\textquoteright}s switch to male production (the {\textquoteleft}switch point{\textquoteright}, SP) accounted for only 22\% of the variation in the onset of the CPh. In some colonies, the CPh even began before the SP. The CPh was more strongly correlated with the transition in queen production (r=0.79). Replacing the queen eggs with male eggs or doubling the number of workers in young colonies resulted in a significantly earlier onset of the CPh and a significantly earlier transition to queen production. Replacing queen eggs with female eggs did not have this effect. These manipulations did not affect the timing of the queen{\textquoteright}s switch from female to male production. These findings show that the mechanism underlying the queen-worker conflict in insect societies is more complex than previously appreciated. The onset of queen-worker conflict cannot be attributed simply to a single factor such as the queen{\textquoteright}s switch to male production or a decrease in queen inhibition. Rather, multiple cues are important.},
	issn = {0962-8452},
	doi = {10.1098/rspb.1999.0947},
	author = {Bloch, G.}
}
@article { ISI:000078988800006,
	title = {Regulation of reproduction by dominant workers in bumblebee (Bombus terrestris) queenright colonies},
	journal = {BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY},
	volume = {45},
	year = {1999},
	month = {FEB},
	pages = {125-135},
	abstract = {The mechanisms of regulating worker reproduction in bumblebees were studied by direct behavioral observations and by measuring ovarian development and juvenile hormone (JH) biosynthesis rates in workers under different social conditions. Workers in the last stage of Bombus terrestris is colony development (the competition phase) had the lowest ovarian development and JH biosynthesis rates. Gallows introduced into colonies immediately after queen removal (dequeened colonies) demonstrated a significant increase in ovarian development before, bur not during, the competition phase. These findings differ from the higher ovarian development in colonies during the competition phase predicted by the prevailing hypothesis that worker reproduction starts in response to a decrease in queen inhibition. Reproduction of callows housed with dominant workers in small queenless groups was inhibited as in queenright colonies. This suggests that the reduced ovarian development and JH biosynthesis rates observed in dequeened and normally developing colonies during the competition phase also reflect inhibition by dominant workers. Thus, two distinct stages of inhibition of reproduction seem to exist: (1) before the competition phase, when the queen slows down worker ovarian development and prevents oviposition; (2) during the competition phase, when dominant workers inhibit ovarian development of other workers. Between these stages there seems to be a temporal {\textquoteleft}{\textquoteleft}window{\textquoteright}{\textquoteright} of enhanced worker reproductive development. The queen{\textquoteright}s typical switch to haploid egg production was not associated with changes in worker ovarian development or JH biosynthesis rates. These findings suggest that regulation of worker reproduction in B. terrestris is not determined by simple changes in the queen{\textquoteright}s inhibition capacity or by the sex of offspring and that the worker{\textquoteright}s role is more important than previously believed.},
	issn = {0340-5443},
	doi = {10.1007/s002650050546},
	author = {Bloch, G. and Hefetz, A}
}
@article { ISI:A1996WA98500002,
	title = {Effects of social conditions on Juvenile Hormone mediated reproductive development in Bombus terrestris workers},
	journal = {PHYSIOLOGICAL ENTOMOLOGY},
	volume = {21},
	year = {1996},
	month = {DEC},
	pages = {257-267},
	abstract = {During the annual life cycle of the bumble bee Bombus terrestris (L.) colony, there is a stage characterized by worker reproduction in the presence of the queen. It has been proposed that this is a result of a decrease in queen inhibition. This hypothesis was examined by studying the effects of queens taken from colonies at different stages of development on several aspects of worker physiology and behaviour: rates of Juvenile Hormone (JH) release in vitro, ovary development, and behaviour associated with reproduction. After optimizing and validating the radiochemical assay for JH release for bumble bee workers, we found that queenless workers had significantly more developed ovaries and higher rates of release of JH than did queenright workers, confirming and extending previous findings that suggest that bumblebee ovarian development is under JH control. Mated queens, separated from their colony and brood, can have the same inhibitory effect on the reproductive development of callow workers. In contrast, workers confined with virgin queens or in queenless groups demonstrated a significantly higher rate of release of JH, overt aggression and threatening behaviours. However, there were no differences in rates of release of JH between workers confined in groups in the laboratory with queens taken from colonies either before or after the onset of worker reproduction. Furthermore, overt aggression and threatening behaviours were similar and low in both types of groups. These results gave no support to the hypothesis that a decrease in queen inhibition is associated with the onset of worker reproduction. We also show that young workers reared in colonies either before or after worker reproduction occurs, or in queenless colonies, all demonstrated similar, low rates of release of JH. These results suggest that older workers may inhibit the corpora allata of younger workers in queenless colonies.},
	issn = {0307-6962},
	doi = {10.1111/j.1365-3032.1996.tb00863.x},
	author = {Bloch, G. and Borst, DW and Huang, ZY and Robinson, GE and Hefetz, A}
}
@article { ISI:A1995TD33800004,
	title = {ESTERASE-ACTIVITY IN POPULATIONS OF THE WHITEFLY, BEMISIA-TABACI (HOMOPTERA, ALEYRODIDAE) - HERITABILITY AND ASSOCIATED ORGANOPHOSPHORUS INSECTICIDE RESISTANCE},
	journal = {BULLETIN OF ENTOMOLOGICAL RESEARCH},
	volume = {85},
	year = {1995},
	month = {MAR},
	pages = {11-19},
	abstract = {The association of esterase (EST) activity with resistance to the organophosphorus (OF) insecticide methidathion was investigated in field-collected populations of whitefly (Bemisia tabaci (Gennadius)) in Israel. The inheritance of EST activity was studied by controlled crosses in the laboratory. Among-family variance of EST activity was highly significant although all families were maintained in the same rearing room. This indicates that genetic or common environmental effects due to rearing each family on a different caged plant must have been important. Heritability estimated from son-mother regression was h(2)=0.98, but this estimate seems to be unrealistically high. Daughter-mother and daughter-mid-parent regressions produced lower heritability estimates (as expected). None of the regression coefficients of daughters on mother, however, were significantly different from zero and the regression on parent explained only very small amounts of the activity variation in the offspring. Estimates obtained from intraclass correlations among offspring were higher and outside the acceptable range, reflecting the variance component due to the common environment. The predictive value of the heritability estimates appears to be very low. The frequency distribution of activity among individuals sampled from one insecticide treated site (AM) was skewed to the right, as previously reported. But samples from another site (TZ) showed a symmetrical distribution, unlike the previous pattern. When field collected individuals from AM were released on clean plants in the laboratory, samples taken from the plants one or more days later showed symmetrical EST distribution. Electrophoretic paterns of field and laboratory samples were the same, but band intensity was stronger in samples from laboratory populations. Differences in mean EST activity between populations and sampling years were unrelated to methidathion resistance.},
	issn = {0007-4853},
	author = {Bloch, G. and WOOL, D}
}
@article { ISI:A1994PK98200005,
	title = {METHIDATHION RESISTANCE IN THE SWEET-POTATO WHITEFLY (ALEYRODIDAE, HOMOPTERA) IN ISRAEL - SELECTION, HERITABILITY, AND CORRELATED CHANGES OF ESTERASE-ACTIVITY},
	journal = {JOURNAL OF ECONOMIC ENTOMOLOGY},
	volume = {87},
	year = {1994},
	month = {OCT},
	pages = {1147-1156},
	abstract = {Artificial selection for increased resistance to methidathion in two replicate lines of the whitefly, Bemisia tabaci (Gennadius) (originating from a cotton-field-collected greenhouse population) was successful; LC(50)s increased 7-8.6-fold in eight generations in the selected lines. This indicates the existence of additive genetic variance for resistance in the source population. Minimal realized heritability estimates, calculated from the response to selection, were h(2) = 0.49 after one generation (with minimal effects of common laboratory environment and inbreeding) and a mean value of h(2) = 0.344 after eight generations. Esterase activity (measured from the hydrolysis of beta-naphthyl butyrate) increased in the selected lines in correlation with resistance. We observed no change in mean esterase activity in the unselected (control) population. No consistent differences in fitness components between selected and control lines were detected during selection, but females exposed to sublethal doses of methidathion tended to have increased fecundity.},
	issn = {0022-0493},
	author = {Bloch, G. and WOOL, D}
}
