Prof. Guy Bloch

Prof. Guy  Bloch

Prof. Guy Bloch

Dept. of Ecology, Evolution & Behavior, The Alexander Silberman Institute of Life Sciences, HUJI. Room 114 Berman Bld. Edmond J. Safra Campus, Givat Ram 91904
p: 02-6584320

Research Interests:

My research interests are the evolution and mechanisms underlying sociality and social behavior, I study bees as a model. The notable ecological success of social insects such as bees is largely attributed to advantages associated with sociality. Bee social organization is astonishing; thousands of individuals coordinate their activities to achieve efficient division of labor, food gathering, and complex migratory (swarming) ventures. In spite of their relatively small and simple nervous system, bees show complex social behavior, elaborated learning and memory capacities, sophisticated navigation skills, and in the case of the honey bee, also a symbolic (dance) language. The availability of the genome sequences of several bee species sets the stage for studying the intricate behavior of bees in molecular terms. Sociality is not only a puzzling proximate enigma, but also an ongoing evolutionary mystery. I am specifically interested in understanding how an insect with a solitary life style was transformed to life in advanced colonial existence with social modulation of almost every aspect of its behavior and physiology.

To study these fascinating and intricate phenomena I integrate analyses at different levels, from genomic to molecular to social. We study plasticity and social regulation of behaviors such as division of labor, dominance, phototaxis (directional response to light), and sleep. The major line of inquiry in my group however, has been the interactions between social factors and the biological clock. Biological clocks time the activity of all plants and animals. In bees the clock is also important for their social organization. We discovered remarkable plasticity in their clock that appears to mesh with their division of labor, a fundamental organization principle of insect societies. Bee larvae require constant care and young "nurse" bees work arrhythmically throughout the day to provide it. In contrast, older bees that typically forage outside the hive have a highly developed internal clock that is used for time-compensated sun compass navigation, dance communication, and for timing visits to flowers. Foragers that are busy collecting nectar and pollen during the day, spend the night in deep rest that shows many features of sleep in mammals and birds. In spite of this, we found that old bees can change their night rest to fulfill with colony needs. If there is a shortage in nurse bees, some of the old foragers revert to nursing behavior and are again active around the clock. We have also discovered similar association between task and circadian rhythms in a bumble bee in which division of labor is associated with body size and not with age as in honey bees. We also study social inluences on the ontogeny of circadian rhythms, and social synchronization (entrainment). One of our exciting findings is that social signals can be stronger time givers to the circadian clock compared with photic signals that are typically the stronger entrianing signals to the clock of animals. These findings provide important support for our hypothesis that plasticity in circadian rhythms in bees was shaped by the evolution of sociality because they improve the integration of individual into an efficient society.

Because the organization principles of the circadian clock as well as the canonical clock genes are conserved in animals, our finding in bees can not only unveil the secrets of insect societies but also have the potential to guide research on plasticity in circadian rhythms and other complex behaviors in other animals.

Affiliations: 

Program in Ecology, Evolution, and Behavior (EEB)
Program of Environmental Studies, The Faculty of Sciences
The Inter-Faculty Program in Biotechnology
The Ring Center for Inter-Disciplinary Environmental Research
The Center for the Study of Rationality