| dc.description | Circadian rhythms are oscillations of approximately 24 hours that regulate the timing
of behavioral and physiological processes and synchronize them with environmental cues.
Although studies in flies and mice have provided unparalleled insights about the cellular and
molecular machinery controlling circadian rhythms, little is known about how this machinery
benefits organisms in their natural habitat, and how the environment shapes the development
and function of the circadian system. Honey bees are an ideal system to address these
questions because they exhibit circadian regulation of ecologically relevant behaviors and
can be studied in both the field and the laboratory. Here I describe the adaptation of the
Drosophila monitoring system for the use of honey bees and social wasps. Using this system,
I show that the social control of temperature at ~35°C during the first 48 hours post
emergence not only plays a key role in the ontogeny of circadian rhythms, but also has long
term effects on the physiological regulation of the circadian clock and life expectancy.
Moreover, I discovered that as we move away from the colony’s center, temperature
oscillates in a circadian manner, and simulating these oscillations is sufficient to entrain
circadian rhythms. A large degree of individual variation in the different circadian
parameters was a landmark of all these experiments, which led me to question if it has a
functional role in the colony. I hypothesized that this individual variation could provide the
basis for a natural form of shift work in bees. Consistent with this hypothesis, I show that
there is a large degree of individual variation in foraging and fanning behaviors and that bees
form temporal clusters (shifts) that can be organized based on their daily and weekly patterns
of these behaviors. Taken together, our findings indicate that colony temperature has a major
impact on the development and function of the circadian system. Furthermore, individual variation in the timing of foraging may guarantee a constant influx of resources from the
environment, while minimizing individual risk. Variation in fanning behavior may contribute
to the stability of colony temperature and could explain the importance of genetic diversity in
temperature regulation. | |
