AbstractHoney bees utilize their circadian rhythms to accurately predict the time of day. This ability allows foragers to remember the specific timing of food availability and its location for several days. Previous studies have provided strong evidence toward light/dark cycles being the primary Zeitgeber for honey bees. Recent work in our laboratory described large individual variation in the endogenous period length of honey bee foragers from the same colony and differences in the endogenous rhythms under different constant temperatures. In this study, we further this work by examining temperature inside the honey bee colony. By placing temperature and light data loggers at different locations inside the colony we uncovered that temperature oscillates with a 24-hour period at the periphery of the colony. We then simulated this temperature oscillation in the laboratory and found that using the temperature cycle as a Zeitgeber, foragers present large individual differences in the phase of locomotor rhythms with respect to temperature. Moreover, foragers successfully entrain to these simulated temperature cycles and advancing the cycle by six hours, resulted in changes in the phase of locomotor activity for the most foragers in the assay. The results shown in this study highlight the importance of temperature as a potential Zeitgeber in the field. Future studies will examine the possible functional and evolutionary role of the observed phase differences of circadian rhythms.
High experience levels delay recruitment but promote simultaneous time-memories in honey bee foragers
