Evaluating the post-copulatory sexual selection hypothesis for genital evolution reveals evidence for pleiotropic harm exerted by the male genital spines of Drosophila ananassae
2014 (English)In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 27, no 12, 2676-2686 p.Article in journal (Refereed) Published
The contemporary explanation for the rapid evolutionary diversification ofanimal genitalia is that such traits evolve by post-copulatory sexual selection. Here, we test the hypothesis that the male genital spines of Drosophila ananassae play an adaptive role in post-copulatory sexual selection. Whereas previous work on two Drosophila species shows that these spines function in precopulatory sexual selection to initiate genital coupling and promote male competitive copulation success, further research is needed to evaluate the potential for Drosophila genital spines to have a post-copulatory function. Using a precision micron-scale laser surgery technique, we test the effect of spine length reduction on copulation duration, male competitive fertilization success, female fecundity and female remating behaviour. We find no evidence that male genital spines in this species have a post-copulatory adaptivefunction. Instead, females mated to males with surgically reduced/blunted genital spines exhibited comparatively greater short-term fecundity relative to those mated by control males, indicating that the natural (i.e.unaltered) form of the trait may be harmful to females. In the absence of an effect of genital spine reduction on measured components of post-copulatory fitness, the harm seems to be a pleiotropic side effect rather than adaptive. Results are discussed in the context of sexual conflict mediating the evolution of male genital spines in this species and likely other Drosophila.
Place, publisher, year, edition, pages
2014. Vol. 27, no 12, 2676-2686 p.
animal genitalia; Drosophila ananassae; laser ablation; pleiotropic harm; post-copulatory sexual selection; precopulatory adaptive function; sexual conflict
IdentifiersURN: urn:nbn:se:uu:diva-236829DOI: 10.1111/jeb.12524ISI: 000346280100010OAI: oai:DiVA.org:uu-236829DiVA: diva2:765560