| dc.description.abstract | Cuticular hydrocarbons (CHCs), comprising alkanes and alkenes, are key components of insect cuticles. They protect terrestrial insects from desiccation and serve as signal molecules in various chemical communication processes. Fruit flies have evolved corresponding CHC profiles to adapt to different environments. In this study, I examined the CHC profiles of two closely related species, Drosophila elegans and Drosophila gunungcola, mainly focusing on the body color morphs and pigmentation gene mutant to investigate the possible association between body color and CHC profiles. According to gas chromatography analysis, I found that the number 13, 23, 24, and 25 compounds are D. elegans specific, and the last three compounds only appeared in male cuticle extracts. Conversely, the number 7 compound was only found in D. gunungcola males. More interestingly, the number 18 compound could be found in D. elegans and male D. gunungcola, but not in female D. gunungcola. Further quantitative comparisons suggested a substantial sex difference in CHC profiles. Among those differences, the number 2, 4, and 12 compounds exhibited consistent sex differences across strains and species. When the CHCs of the same sex were compared, no matter intra- or inter-specifically, the numbers of compounds exhibiting significant differences in male comparisons were higher in female comparisons. Several CHCs of the yellow mutant strain significantly differed from the wildtype counterpart in my original analysis. However, those differences diminished after the flies were undergone a cross for genetic background control. Overall, my study showed the inter-specific diversity and inter-specific diversification of CHC profiles, potentially involved in reproductive isolation, in this pair of closely related species. That more compounds exhibiting intra- and inter-specific differences in male cuticles is also consistent with the fast male hypothesis. Moreover, there are substantial differences in CHC profiles between two body color morphs of D. elegans. But whether those CHC differences are determined by the genetic variants controlling body color difference is uncertain. | en_US |