The role of the gut microbiome in honey bee thermoregulation

Social insects are well poised to deal with challenges in their environment; however, we have a poor understanding of how social insects work together to enact change in their environment. Recently, the gut microbiome, a well-known modulator of neurophysiology in mammalian research, has risen as a potential modulator of insect behavior, but how gut microbes affect social behavior remains unknown. Western honeybees (Apis mellifera) are eusocial insects whose small gut community is critical to their neurophysiology, behavior, and social organization, making them an ideal model organism to study social-host-microbe interactions. Fanning is a thermoregulatory behavior performed by middle-aged workers called fanners to optimize colony temperatures for proper offspring development. Fanning is dependent on neurophysiological, environmental, social cues, and thus can be used to investigate the effect of the gut microbiome on behavior on multiple social scales. To investigate the gut microbiota as a modulator of this behavior, our hypothesis was that presence of gut microbes influences fanning. We reared microbiota-depleted bees and inoculated a subset with gut microbes isolated from fanners. We then assessed and compared bees’ fanning capabilities in small groups of 5. Quantitative PCR and 16S rRNA sequencing were used to analysis gut communities. We then used video tracking to determine whether interactions were disrupted. We predict that microbiota-depleted bees are significantly less likely to fan and fan at higher temperature thresholds, likely due to fewer interactions. This work contributes key insight into the extent to which gut bacteria affect societal dynamics.