Collective Aggregation via Directed Pheromone Signaling in Honeybee Swarms

While pheromones are a prevalent volatile communication signal in nature, the range and noise tolerance of information exchange is limited by the spatiotemporal decay of these signals. Using honeybees as a model organism, we study the communication network of honeybee swarms that locate their queen by tracking her pheromones. Specifically, how can honeybees that are far away from the queen locate her? Our results suggest that bees who locate her pheromones, stop at a certain distance from her, raise their abdomens and fan their wings, driving airflow across the Nasonov gland, which disperses pheromones to the rest of the swarm. We show that bees arrange in a specific spatial distribution with a characteristic distance between individuals and a characteristic direction in which individuals broadcast the signal. This dynamic structure recruits new broadcasting bees over time as the pheromones traveled a distance which is orders of magnitude the size of an individual. We connect our experimental results to an agent based model of volatile communication network, and characterize the advantage of this directional communication strategy vs. an axisymmetric one.