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) communication. 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. Honey 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 rather than age as in honey bees, and in ants in which age-related division of labor evolved independently. We also study social influences on the ontogeny of circadian rhythms, and social synchronization (entrainment). One of our recent exciting findings is that social signals can override photic entrainment which is considered to be the stronger time giver to the animal clock. Taken together, our "sociochronobiology" research provides important support for the hypothesis that plasticity in circadian rhythms in bees was shaped by the evolution of sociality because it improves the integration of individuals into an efficient society. Another important line of research aims to understand the molecular, endocrine, and sociobiological bases of division of labor and regulation of reproduction in bumblebees. This line of inquiry has far-reaching agricultural implications because bumblebees are the second most important pollinators in Israel and world-wide.