Choosey females: The mechanism of fecundity block in Drosophila melanogaster

Social interactions are essential for reproduction and survival from microorganisms to humans. Individuals rely on complex recognition systems to regulate their interactions with conspecifics, kin, and potential mates. A classical model for the study of recognition is the Bruce effect in which recently mated female mice block pregnancy when exposed to the scent of unrelated males. We recently showed a similar phenomenon in the fruit fly Drosophila melanogaster: females who normally mate and reproduce with related males remain infertile when such mating occurs in the presence of unrelated males. This phenomenon is strikingly similar to the Bruce effect, which has never been documented in an invertebrate. The aim of this proposal is to bring the study of the ?Bruce effect? to the powerful toolkit of Drosophila melanogaster. A classic idea of neuroscience is that behaviours are controlled by an interaction between genes, physiology, and neuronal circuits. Using genetic tools, we propose to dissect the mechanisms, from sensory input to behavioural output, that allow Drosophila females to discriminate related males from unrelated ones and to selectively control fecundity. We will identify male pheromones as well as female sensory and motor neurons to reconstruct the circuitry underlying female discrimination. Because this behaviour is observed in vertebrates, work stemming from this proposal may help develop novel hypotheses in these species. It will be of tremendous interest for our understanding of the evolution of sociality to find out whether the means by which the social brain processes information in Drosophila translate to other species.