Antibiotics increase aggression behavior and aggression-related pheromones and receptors in Drosophila melanogaster

Abstract

Aggression is a behavior common in most species; it is controlled by internal and external drivers, including hormones, environmental cues, and social interactions, and underlying pathways are understood in a broad range of species. To date, though, effects of gut microbiota on aggression in the context of gut-brain communication and social behavior have not been elucidated. We examine how manipulation of Drosophila melanogaster microbiota affect aggression as well as the pathways that underly the behavior in this species. Flies treated with antibiotics exhibited significantly more aggressive behaviors. Furthermore, they had higher levels of vCA and (Z)-9 Tricosene, pheromones associated with aggression in flies, as well as higher expression of the relevant pheromone receptors and transporters OR67d, OR83b, GR32a, and LUSH. These findings suggest that aggressive behavior is, at least in part, mediated by bacterial species in flies.