Networks of sexually dimorphic neurons that regulate social behaviors in Drosophila.

Neural mechanisms underlying sexually dimorphic social behaviors remain enigmatic in most species. In Drosophila, sexually dimorphic pC1/pC1x neurons have been described as a site of sensory integration that regulates mating and aggressive behaviors. We show that the male pC1/pC1x population resides in an expansive and highly intertwined male-specific network that is poised to regulate social behavior. The 48 pC1/pC1x connectomically defined cell types exhibit heterogeneous synaptic connections, and a subset receive strong input from identified sensory pathways. Genetic driver lines for these cell types were generated and used to discover distinct roles for pC1/pC1x cell types in modulating social acoustic signaling and male-male interactions. We also describe circuit motifs by which pC1 and sexually dimorphic aIPg neurons co-regulate social behaviors. Our results reveal unexpected diversity in the connectivity and behavioral roles of pC1/pC1x cell types and provide essential genetic tools for interrogating their neurophysiological and behavioral functions.