A social bee (Bombus terrestris) learns to associate a novel odor with social context

Many pheromone responses are hardwired into the insects nervous system and are essential for critical behaviors such as mating, alarm signaling, and trail following. Workers of social species are assumed to respond innately to queen pheromones, affecting their behavior and reproductive physiology. However, accumulating evidence suggests that learning and experience may also shape responses to social chemical cues. To examine if the response to queen-associated odors can be learned, we exposed Bombus terrestris workers to a novel odor by treating the queen daily with unfamiliar floral scents, either anisyl alcohol or methyl anthranilate. We allowed perfumed queens to establish colonies and examined worker attraction and egg laying following exposure to these odors in the absence of the queen either with or without brood as context. In a two-choice olfactometer, workers preferred the queen odor they learned during colony development. Exposure of workers to the queen-associated odor in the absence of the queen influenced worker egg laying only in the presence of brood, surprisingly resulting in increased egg laying. Our study demonstrates that workers can learn novel odors that are associated with their queen or nest, which in turn function as context-dependent social cues that modify their social and reproductive behavior.