The effects of density on behavior in the flesh fly, Sarcophaga crassipalpis

We examined the effects of density on interactive aggression and locomotor activity in the flesh fly, Sarcophaga crassipalpis. Previous studies have demonstrated that male flies show a territorial behavior in the wild and that this can be modeled in a minimal environment in the lab. Aggressive interactions show an ontogeny development with these behaviors rapidly increasing on day 3 after emergence, concurrently with sexual maturity. This study examined the effects of rearing density on aggression levels. Individual fly pairs were filmed from density housing groups of 1,6, and 25 flies/container on day 4 when aggressive behavior occurs. The fly’s aggressive interactions were scored from the video. Data suggests that aggression is reduced significantly in the housing density of 25 where densities of 1 and 6 are statistically the same. This data suggests that the aggressive behavior changes depending on the rearing density of the flies. To analyze if activity levels played a role in the change in aggression, flies were once again kept in different densities groups as before and placed into an activity monitor. The activity levels suggest that there is no change between the different density groups.