Adaptations and mechanical memory in honeybee swarms in response to temperature changes

Honeybee swarms, consisting of a queen bee and thousands of workers, hang suspended from structures in nature for periods ranging from hours to several days while searching for a new hive. During this time, the swarm is subject to dynamic environmental forces including wind, rain, and temperature fluctuations. Individual bees respond to local cues, such as pheromones, tension in bee-bee bonds, and environmental factors, by making topological and geometric changes to their connections with neighboring bees. These changes in bee-bee bonds give rise to both local and global changes in the swarm's network architecture and morphology, which, in turn, modify the microenvironment within the swarm, driving a continual cycle of adaptation and self-optimization of the physical network to buffer against environmental perturbations. Using X-ray computed tomography as a lens into the swarm, we characterize the evolution of the swarm's structure in response to ambient temperature fluctuations. We find that a thermally-induced mechanical memory in the swarm leads to hysteresis and distinct morphological adaptations during heating and cooling. Additionally, we explore the trade-offs faced by individual bees and the swarm as a whole while optimizing competing biological objectives, such as maintaining mechanical stability, thermoregulation, and cohesion.