The females' response to male attractiveness: Mate choice, larvae production and differential brain protein expression

Sexual Selection has been studied predominantly from a functional perspective with relatively limited investigation of the mechanistic basis of female choice. In this study, we evaluated female choice and larvae production in response to attractive or less attractive males and concurrently examined the protein profile in the brains of females, using the mealworm beetle Tenebrio molitor as a model system. Females were found to prefer males with high levels of pheromones, which requires the secretion of juvenile hormone (JH). Male attractiveness was enhanced using the JH analog methoprene, resulting in less female rejection and higher mating frequency and offspring production. Importantly, reproductive success was not due to differences in testis size or sperm production, or viability. Out of the 1833 proteins detected in the brain, only 32 were differentially expressed in females mating with attractive versus less attractive males. These proteins involved memory, metabolism, olfactory detection, reproduction, and movement. Although some brain proteins have been linked to mate choice in vertebrates, most of the differentially expressed molecules found in this study have not been previously reported concerning mate choice.