Social information supersedes sensory information to drive collective thermoregulatory behavior

Collectively utilizing information about environmental conditions is important for social insects to thermoregulate. One way honeybee (Apis mellifera) workers thermoregulate developing offspring near 35°C, the optimal temperature for development, is through fanning if temperatures exceed the optimum. Additionally, this important thermoregulatory behavior is context dependent, where groups of worker bees are more likely to fan than isolated bees. The Apis mellifera Hymenoptera-specific transient receptor potential A (AmHsTRPA) channel is activated around 34°C so it’s likely that TRP channel function is important for initiating thermoregulatory fanning. We investigated the importance of the AmHsTRPA channel for thermoregulatory fanning by administering a known TRP channel blocker to bees in groups of 10 and performing behavioral assays where heated bees were observed for instances of fanning. We found that groups of bees treated with TRP blocker are less likely to fan than untreated bees and if they do begin fanning, it is initiated at higher temperatures compared to groups of untreated bees supporting our hypothesis that TRP channels are important for thermoregulatory fanning. To understand how the combination of social and thermal information influence thermoregulatory fanning, we performed behavioral assays on mixed groups of untreated bees and bees treated with TRP blockers. Our results indicate that the ratio of bees sensing temperature in a group changes the likelihood of fanning and the temperature when a group initiates fanning. By disentangling these two discrete types of information we can better understand how social insects coordinate complex behaviors that scale to colony-level.