The evolutionary conserved role of a male-specific sex pheromone on courtship inhibition in Drosophila.

Abstract

Drosophila pheromones in the form of long-chain hydrocarbons expressed on the cuticle for species identification and to facilitate reproduction. One primary aim of this study was to investigate whether expression and function of a male-specific sex pheromone is conserved in various drosophilids. While CH503 was shown to inhibit courtship when transferred to female during copulation in Drosophila melanogaster male, its effect on other Drosophila was unknown even though the pheromone was detected in several related species. This project employed ultraviolet laser desorption mass spectrometry, a method that allowed detection of more polar pheromones. A second primary aim was to determine the stereostructure of CH503 in different species of drosophilids. CH503 is naturally produced as (R)-isomer in D. melanogaster, but the synthetic (S)-isomer was shown to display more potent courtship inhibiting activity. Here, it was demonstrated that both CH503 isomers suppressed courtship in all 7 species with varying efficacy, even in distantly related species. This result illustrates the evolutionary conserved role of CH503 as an anti-aphrodisiac and suggests that the neural circuits of courtship inhibition by the pheromone are ancient and preserved in Drosophila.