Sociability is a Multidimensional Trait in Drosophila melanogaster

Sociability-the propensity of an individual to engage in group activities-is a trait present in all social species. In humans and many animals, sociability varies between individuals yet remains consistent across contexts, qualifying it as a personality trait. Sociability influences health and physiology, but the mechanisms underlying sociability and its inter-individual variation remain poorly understood. The genetically tractable fruit fly, Drosophila melanogaster, is increasingly used to study social behavior and exhibits a wide range of sociability phenotypes. However, previous studies have relied on distinct behavioral paradigms, limiting cross-context comparisons and motivating a more extensive characterization of sociability in this species. Here, we quantified sociability in D. melanogaster using a multidimensional approach encompassing three paradigms that capture engagement in group activities across contexts: (1) preference for communal versus solitary egg-laying, (2) egg-laying latency in a group, and (3) frequency and duration of spontaneous social interactions and interindividual distance. We assessed these behaviors in 105 lines of the Drosophila Genetic Reference Panel and observed substantial variation in responses to conspecific presence across paradigms. Sociability-related behaviors differed between genetically distinct lines, indicating a genetic component. However, the three sociability traits were uncorrelated, demonstrating that sociability in D. melanogaster is multidimensional. These findings suggest that sociability is not governed by a single central mechanism, but instead arises from multiple context-dependent pathways.