How sexual features and preferences originate and evolve is one of the most important and contentious problems in evolutionary biology. In some species, females choose male traits that indicate genetic quality or confer benefits. Thus, male traits and female preferences are assumed to originate at the same time and to coevolve. In contrast, sensory exploitation occurs when males take advantage of females’ preexisting sensory biases. We show in Drosophila sensory exploitation of males by other males through the use of a pheromone to gain sexual advantage. Notably, sensory exploitation leads to male sensory adaptation. These findings provide a mechanism for the evolutionary origins of a pheromone and are a previously unidentified example of sensory exploitation between males.

Abstract

Animals exhibit a spectacular array of traits to attract mates. Understanding the evolutionary origins of sexual features and preferences is a fundamental problem in evolutionary biology, and the mechanisms remain highly controversial. In some species, females choose mates based on direct benefits conferred by the male to the female and her offspring. Thus, female preferences are thought to originate and coevolve with male traits. In contrast, sensory exploitation occurs when expression of a male trait takes advantage of preexisting sensory biases in females. Here, we document in Drosophila a previously unidentified example of sensory exploitation of males by other males through the use of the sex pheromone CH503. We use mass spectrometry, high-performance liquid chromatography, and behavioral analysis to demonstrate that an antiaphrodisiac produced by males of the melanogaster subgroup also is effective in distant Drosophila relatives that do not express the pheromone. We further show that species that produce the pheromone have become less sensitive to the compound, illustrating that sensory adaptation occurs after sensory exploitation. Our findings provide a mechanism for the origin of a sex pheromone and show that sensory exploitation changes male sexual behavior over evolutionary time.