AbstractSensory communication depends on the precise matching between the emission and the perception of sex- and species-specific signals; understanding both the coevolutionary process and the genes involved in both production and detection is a major challenge. desat1 determines both aspects of communication—a mutation in desat1 simultaneously alters both sex pheromone emission and perception in Drosophila melanogaster flies. We investigated whether the alteration of pheromonal perception is a consequence of the altered production of pheromones or if the two phenotypes are independently controlled by the same locus. Using several genetic tools, we were able to separately manipulate the two pheromonal phenotypes, implying that desat1 is the sole gene responsible, exerting a pleiotropic effect on both transmission and detection. The levels of the five desat1 trancripts, measured in the head and body of manipulated flies, were related to variation in pheromone production. This suggests that the pleiotropic action of desat1 on pheromonal communication depends on the fine regulation of its transcriptional activity.