Interacting fruit flies synchronize behavior

Social behaviors are ubiquitous and crucial to an animals survival and success. The behaviors an animal performs in a social setting are affected by internal factors, inputs from the environment, and interaction with others. To quantify social behaviors, we need to measure both the stochastic nature of behavior of isolated individuals and how these behaviors change as a function of the environment and features of social interaction. We probed the behavior of male and female fruit flies in a circular arena as individuals and within all possible pairings. By combining measurements of the animals position in the arena with an unsupervised analysis of their behaviors, we fully define the effects of position in the environment and the presence of a partner on locomotion, grooming, singing, and other behaviors that make up an animals repertoire. We find that geometric context tunes behavioral preference, pairs of animals synchronize their behavioral preferences across trials, and paired individuals display signatures of behavioral mimicry.