Optogenetic activation of the fruitless-labeled circuitry in Drosophila subobscura males induces mating motor acts

It remains an enigma how the nervous system of different animal species produces different behaviors. We studied the neural circuitry for mating behavior in Drosophila subobscura, a species that displays unique courtship actions not shared by other members of the genera including the genetic model D. melanogaster, in which the core courtship circuitry has been identified. We disrupted the D. subobscura fruitless (fru) gene, amasterregulatorforthecourtshipcircuitryformationinD. melanogaster, resultingincompletelossof matingbehavior. We also generated fru^soChrimV, which expresses the optogenetic activator Chrimson fused with a fluorescent marker under the native fru promoter. Thefru-labeledcircuitryinD. subobscuravisualizedbyfru^soChrimV revealeddifferences betweenfemales andmales, optogeneticactivation of which in males induced mating behavior including attempted copulation. These findings provide a substrate for neurogenetic dissection and manipulation of behavior in non-model animals, and will help to elucidate the neural basis for behavioral diversification.