Evaluating the postcopulatory sexual selection hypothesis for genital evolution reveals evidence for pleiotropic harm exerted by the male genital spines of Drosophila ananassae

The contemporary explanation for the rapid evolutionary diversification of animal 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 adaptive function. Instead, females mated to males with surgically reduced/blunted genital spin...

当前学界对动物生殖器快速演化分化的主流解释为，这类性状通过交配后性选择（post-copulatory sexual selection）演化而来。本研究旨在检验安娜果蝇（Drosophila ananassae）的雄性生殖器棘突在交配后性选择中具有适应性功能这一假说。尽管此前针对两种果蝇的研究表明，这类棘突可通过交配前性选择（precopulatory sexual selection）启动生殖器结合并提升雄性在竞争中的交配成功率，但仍需开展进一步研究以评估果蝇生殖器棘突是否具备交配后功能。本研究采用高精度微米级激光手术技术，探究棘突长度削减对交配时长、雄性竞争性受精成功率、雌性繁殖力以及雌性再次交配行为的影响。本研究未发现该物种雄性生殖器棘突具备交配后适应性功能的证据。与之相反，与经手术削减/钝化生殖器棘突的雄性交配的雌性...