Honey bees (Apis mellifera) provide a tractable system for studying the behavioral consequences of eusociality. As eusocial insects, honey bees live in colonies comprised of thousands of sterile female workers with only one reproductively active queen. Therefore, a sterile worker’s own genetic fitness is best served by acting in the interest of her colony, even if her behavior curtails her own lifespan. In this study, we tested the hypothesis that developmentally stressed worker bees remove themselves from the hive to protect their colony from the negative costs of an inefficient workforce. To confirm that this self-removal behavior is a reaction to severe stress, and not parasite-driven or a social immunity response, we developmentally stressed bees with either cold shock or parasitization by Varroadestructor mites. Stressed bees, as well as their control counterparts, were tagged upon emergence and introduced to a common observation hive. We took daily attendance of the focal bees and checked a trap engineered to capture prematurely exiting bees every hour. For both treatments, we found that bees stressed by either mites or cold temperatures lived for significantly less time and prematurely exited the hive in significantly higher numbers than their control counterparts. This indicates that self-removal behavior is probably stress driven. Going forward, we plan to measure the hypopharyngeal glands and juvenile hormone titers of the bees that prematurely exited to further confirm the drivers of this behavior. This will ultimately enable us to model the effects of this behavior on the entire colony.
