Natural variation in sociability among Drosophila melanogaster

Sociability – an individual’s propensity to engage in group activities – is a conserved trait throughout most of life. Sociability can be considered as a personality type in humans when showing correlated sociability measures across different assays. Our knowledge of the mechanisms that drive sociability and explain its inter-individual variation is still limited. To enhance our mechanistic understanding, the genetically tractable Drosophila melanogaster is increasingly being used as a model for research on social behaviour. High and low sociability phenotypes, indicative of a variation of sociability levels among the population have been documented in this species. However, sociability traits have been measured through unidimensional assays, which do not allow us to assess whether sociability is a personality type in fruit flies. Here, we present a multidimensional approach to assess sociability, using a combination of three behavioural assays that each captures a different functional feature of social interactions in D.melanogaster. We applied our approach to the Drosophila melanogaster Genetic Reference Panel (DGRP) lines and revealed continuous variation in the strength of response to others. We found that sociability levels varied between genetically distinct lines, indicative of a genetic component of sociability.The three sociability traits were, however, not correlated, making it questionable whether sociability can be considered a personality type in D. melanogaster.