Genetic identification and separation of innate and experience-dependent courtship behaviors in Drosophila.

Wild-type D. melanogaster males innately possess the ability to perform a multistep courtship ritual to conspecific females. The potential for this behavior is specified by the male-specific products of the fruitless (fruM) gene; males without fruM do not court females when held in isolation. We show that such fruM null males acquire the potential for courtship when grouped with other flies; they apparently learn to court flies with which they were grouped, irrespective of sex or species and retain this behavior for at least a week. The male-specific product of the doublesex gene (dsxM) is necessary and sufficient for the acquisition of the potential for such experience-dependent courtship. These results reveal a process that builds, via dsxM and social experience, the potential for a more flexible sexual behavior, which could be evolutionarily conserved as dsx-related genes that function in sexual development are found throughout the animal kingdom.