Zeh J A, Newcomer S D, Zeh D W
Department of Biology and Biochemistry, University of Houston, Houston, TX 77204-5513, USA.
Proc Natl Acad Sci U S A. 1998 Nov 10;95(23):13732-6. doi: 10.1073/pnas.95.23.13732.
In most animal species, particularly those in which females engage in polyandry, mate choice is a sequential process in which a female must choose to mate or not to mate with each male encountered. Although a number of theoretical and empirical investigations have examined the effects of sequential mate choice on the operation of sexual selection, how females respond to solicitation by previous mates has received little attention. Here, we report the results of a study carried out on the polyandrous pseudoscorpion, Cordylochernes scorpioides, that assessed the sexual receptivity of once-mated females presented after a lapse of 1.5 hr or 48 hr with either their first mate or a different male. Females exhibited a high level of receptivity to new males, irrespective of intermating interval. By contrast, time between matings exerted a strong effect on female receptivity to previous mates. After a lapse of 48 hr, females did not differ significantly in their receptivity toward previous mates and different males, whereas at 1.5 hr after first mating, females were almost invariably unreceptive to males from whom they had previously accepted sperm. This result could not be attributed to male size or mating experience or to male sexual receptivity. Indeed, males were as willing to transfer sperm to a previous mate as they were to a new female. This difference between males and females in their propensity to remate with the same individual may reflect a conflict between the sexes, with males seeking to minimize postcopulatory sexual selection and females actively keeping open the opportunity for sperm competition and female choice of sperm by discriminating against previous mates.
在大多数动物物种中，尤其是那些雌性进行多配偶交配的物种，配偶选择是一个连续的过程，在此过程中，雌性必须选择是否与遇到的每只雄性交配。尽管许多理论和实证研究都考察了连续配偶选择对性选择运作的影响，但雌性如何回应前配偶的求爱却很少受到关注。在这里，我们报告了一项对多配偶拟蝎Cordylochernes scorpioides进行的研究结果，该研究评估了在间隔1.5小时或48小时后，已交配过一次的雌性与它们的第一任配偶或不同雄性再次接触时的性接受能力。无论交配间隔时间如何，雌性对新雄性都表现出高度的接受能力。相比之下，交配间隔时间对雌性对前配偶的接受能力有很大影响。在间隔48小时后，雌性对前配偶和不同雄性的接受能力没有显著差异，而在第一次交配后1.5小时，雌性几乎总是拒绝那些它们之前接受过精子的雄性。这一结果不能归因于雄性的体型、交配经验或雄性的性接受能力。事实上，雄性向之前的配偶输送精子的意愿与向新雌性输送精子的意愿是一样的。雄性和雌性在与同一个体再次交配倾向上的这种差异可能反映了两性之间的冲突，雄性试图尽量减少交配后的性选择，而雌性则通过歧视前配偶，积极为精子竞争和雌性对精子的选择保留机会。
