Assistant Professor Michigan State University East Lansing, Michigan
Sexual dimorphism is found in many organisms in nature. In many cases, some sexually dimorphic traits can evolve into dramatical differences between two sexes, providing a great diversity of flamboyance and beauty in nature. Some examples include the male peacock’s colorful tail versus the peahen’s drabber body, and the male lion’s luxuriant mane versus the lioness’s bald head. These exaggerated traits exist in male and contribute to female mate choice. However, our mechanistic understanding about these exaggerated traits is limited, especially the exaggerated traits existing in females that coevolve with male mate choice. In this study, we selected cuticular hydrocarbons (CHCs) in Drosophila erecta as a model to investigate this question. We have found female D. erecta sex- and species-specifically produces very long CHCs (diene) within melanogaster subgroup, whereas male D. erecta greatly rely on female CHCs as contact pheromones to initiate courtship. We concluded that the very long CHCs in D. erecta represent a female exaggerated trait, and found that this female exaggerated trait was generated by a sex-specific expression of one fatty acyl-CoA elongase gene (responsible for the very long carbon chain) in the CHC synthesis pathway. We are currently working on dissecting the possible transcription factors that get involved in producing such an interesting sexually dimorphic expression pattern, on the 5’ non-coding region of this gene. We expect this work will provide us with new insight of the evolution of female exaggerated trait and male mate choice.