Multimodal social context modulates larval behavior in Drosophila

All animals need to navigate and make decisions in social environments. They influence each other's behavior, but how important this is and how they process and represent social information in their brain are less well understood. This includes fruit flies and larvae, usually not known as "social insects." Using a Drosophila larva assay with reduced stimulation, we found that groups show enhanced dispersal and distance from each other in the absence of food. This social context-dependent modulation overrides responses to many external sensory cues and is shaped by developmental social experience. Leveraging the genetic toolbox available in Drosophila, we find that different sensory modalities are required for social context modulation. Our results show that even less social animals such as fly larvae are affected by conspecifics and recognize each other through multimodal sensory cues. This study provides a tractable system for future dissection of the neural circuit mechanisms underlying social interactions.