Lateralized and bilateral sensory mechanisms independently regulate sociability and social preference in Drosophila

Social behavior involves sociability—the drive to interact—and social preference—the choice of partners. Using FlySocialer, an automated system for tracking group interactions, we analyzed male Drosophila melanogaster and found highly individualized, non-random social behaviors. Compared to randomized controls, flies showed stable individual differences in sociability and distinct partner preferences. Sociability exhibited a sensory-specific lateralized asymmetry: visual inputs via the left eye modulated interaction number, while olfactory inputs via the left antenna influenced interaction duration. Conversely, neither sensory manipulation exerted a significant effect on social preference. These results reveal distinct mechanisms for sociability and selectivity, highlighting lateralized sensory drive versus bilateral integration as core principles of social behavior in Drosophila.