Abstracts (first author)
Rapid evolution in the wild: unravelling the genetic basis of a wing mutation in field crickets
The field cricket Teleogryllus oceanicus is a textbook example of rapid evolution in the wild, but little is known about the genetics of this intriguing system. In Hawaii, a mutant variety of silent male crickets has recently arisen and spread in several populations, apparently in response to pressure from an acoustically-orienting parasitoid. The mutation, flatwing, first appeared on the island of Kauai in 2003, but it has since appeared on the neighbouring island of Oahu. It segregates as a sex-linked, sex-limited Mendelian trait in both populations, and it feminizes male wings by erasing the specialized sound-producing structures of a normal wing. The degree of feminization, however, varies between islands. Does this represent convergent evolution, or has gene flow introduced the mutation(s) into a different genomic background, resulting in different phenotypic manifestations? To pinpoint where the mutation or mutations reside within the genome, and to help answer this question, we applied Bulked Segregant Analysis (BSA) using RAD-seq in two different populations with distinct flatwing phenotypes and abundances: Kauai (>95% of males are flatwing, with heavily feminized wings), and Oahu (ca. 50% of males are flatwing, with less strongly feminized wings). We have identified the first group of candidate SNP markers associated with the flatwing phenotypes in each population. Using these, we tested different evolutionary hypotheses that could explain why there is a difference in mutant wing morphology between the two populations. The results provide insight into how convergent phenotypes arise and evolve in real-time, in the wild.