The Function of Pigmentation Genes in the Development and Evolution of Drosophila Mating Behavior

Abstract

Phenotypic evolution within and between species involves correlated changes in traits that facilitate survival and reproduction. Mating behaviors, in particular, and their correlated anatomical structures enable animals to court and reproduce with mates using a mixture of visual, chemical, and mechanical cues. How genes and genomes evolve to generate correlated differences in these traits is unclear. In this thesis, I investigate how genes and genomes contribute to correlated differences in mating behavior and pigmentation in Drosophila. Using tissue-specific genetic manipulations, I illustrate how the yellow gene influences male mating success through its function in melanizing a secondary sexual character; using CRISPR/Cas9 genome editing, I demonstrate a role of the ebony and tan genes in cuticular hydrocarbon synthesis and natural variation; and using multiplexed shotgun genotyping, I map the genomic location of species differences in wing pigmentation and mating display, identifying new genes involved in pigmentation evolution and new evidence explaining how behavior and anatomy evolve together. Together, these data show 1) that behavioral development and evolution involves correlated changes in structures that animals use to interact with their environment, 2) that changes in these structures correlate with the behaviors that use them, 3) that changes in individual genes can generate these differences, and 4) that complex evolution of sex chromosomes can explain species correlated differences in sex-specific behavior and anatomy.