Explaining the origin of complex morphological innovations, in particular conspicuous male ornaments, remains one of the most challenging and exciting questions in the field of evolution. Indeed, conspicuous male-specific traits, either displayed to females during courtship, or used as weapons in battles, likely represent liabilities and should be opposed by natural selection. Darwin proposed that sexual selection is responsible for the evolution of these sexual traits. Since Darwin's time this hypothesis has received considerable theoretical and empirical support. Sexual selection is now perceived as a pervasive force shaping sexual communication systems, acting both on male signaling traits and female preference for these traits. Beyond this generic setup, however, the genetic mechanisms underlying the evolution of male ornaments, and the female preference for these traits, remain largely elusive.The objective of this project is to decipher the genetic mechanisms underlying the evolution of a sexual communication system in Drosophila species that have evolved a novel male-specific wing pigmentation pattern displayed to females during courtship. We will examine the emergence, the diversification, and the independent evolution of the male wing pigmentation pattern.We will in particular (i) determine the genetic architecture underlying the formation of the male wing spot in Drosophila biarmipes; (ii) map the genetic sources of male wing spot divergence among species (shape, color, and intensity); (iii) identify the genetic and functional bases of the recurrent evolution of the wing spot, and (iv) characterize the nature of the female’s reproductive preference.By embracing a multi-scale, integrated approach, the ambition of this project is to shed a new light on the evolution of sexual communication systems in animals.