Experimentally-Imposed Evolution of Drosophila athabasca

          Identifying the specific genetic and phenotypic changes that drive speciation and reproductive isolation is pivotal in understanding how and why evolution happens. The focus of this project is to determine whether sexual selection can result in the development of a new species. Drosophila remains an established and well-studied model organisms for evolutionary research. In particular, the species Drosophila athabasca (D. athabasca) resulted from extremely rapid divergence.  In addition to having virtually complete sexually isolated races or sub-species, this complex makes for an excellent system for the study of speciation. All D. athabasca races (EA, EB, and WN) have diverged quite recently on the evolutionary time scale. Additionally, recent studies indicated that this isolation is due solely to female mating preferences and have ruled out all alternative sexual isolation traits. The goal of this project is to mimic a case of speciation through male courtship song by facilitated artificial selection. Previous studies have shown that females of the D. Athabasca species differentiate between males based on the inter-pulse interval (IPI) which is the time between each peak in the sound waves of their courtship songs. Because the males of the EA race of D. Athabasca have a wide range of inter-pulse interval (IPI), it is theoretically possible to drive the IPI towards the extreme ends of the spectrum. The result would be a two population of EA Drosophila that would have a very short IPI and very high IPI, such that they would be sexually isolated from the control EA population. This project proves several necessary components that are important to understand the speciation of the D. athabasca complex: a) that the male courtship song is a genetic and heritable trait, and b) that there is enough standing genetic variation within the EA population that rapid speciation can occur if and when female preference changes.