The gut microbiota affects the social network of honey bees

The gut microbiota influences animal neurodevelopment and behavior but has not previously been documented to affect emergent group-level properties of social organisms. Here we use honeybees to probe the effect of the gut microbiota on host social behavior. We found that the microbiota increased the rate of interaction between bees and the complexity of the emergent colony social network. Microbiota colonization was associated with higher abundances of one third of the metabolites detected in the brain, including amino acids with roles in synaptic transmission and brain energetic function. A subset of these metabolites were significant predictors of the number of social interactions of bees. Microbiota colonization also affected brain transcriptional processes related to amino acid metabolism and epigenetic modifications, particularly in areas of the brain implicated in sensory perception. These results demonstrate considerable effects of the gut microbiota on honeybee social organization and highlight the associated changes in individual neurophysiology.