Chemical Mate Choice Copying in <i>Drosophila melanogaster</i>

AbstractMate choice is a critical decision, especially for females, that requires time and energy to assess potential partners' genetic quality. Consequently, in many species, females have evolved the ability to utilize social information by copying the mate choices of others, usually based on visual cues. However, many species, especially invertebrates, primarily rely on chemical not visual cues. Using chemical rather than visual cues provides several advantages, such as not requiring active observation of copulations. Despite that, empirical evidence for the existence of chemical mate choice copying is scarce. Using <i>Drosophila melanogaster</i>, we provide the first demonstration of chemical mate choice copying. Females exposed to a recently mated female select the same male genotype that the demonstrator female mated with at a higher frequency than expected by chance. Chemical mate choice copying requires sensing both male and female cues, which might indicate that other females have chosen that male genotype. Our work suggests that females, in the presence of mated females, increase choosiness at the virgin stage, elevating sexual selection on male traits. This study provides novel evidence that exploiting social information is more prevalent in flies than previously assumed.