Friesen Christopher R, Uhrig Emily J, Mason Robert T
School of Biological Sciences, University of Sydney, Sydney, Australia; Department of Integrative Biology, Oregon State University, Corvallis, Oregon.
J Exp Zool A Ecol Genet Physiol. 2014 Dec;321(10):603-9. doi: 10.1002/jez.1892. Epub 2014 Nov 3.
Polyandry is a source of sexual conflict and males often try to limit female promiscuity. Consequently, male manipulation of receptivity via antiaphrodisiacs and copulatory plugs that prevent female remating can be a source of sexual conflict. This sexual conflict may be intensified when females must remate for fertility insurance. Male red-sided garter snakes produce a large, gelatinous copulatory plug that has been proposed to 1) physically prevent remating and 2) contain an antiaphrodisiac that reduces female receptivity. These males may become sperm depleted because of their dissociated reproductive pattern. If a female mates with a sperm deficient male and is also rendered unreceptive to further mating, then this represents a serious conflict. We tested whether female remating frequency is affected when females are mated with a male that produces a sperm-less copulatory plug. We show that females are significantly more likely to remate after mating with vasectomized males than intact males, even though vasectomized males still produce a copulatory plug. These results suggest that the ejaculate material of the plug does not contain an antiaphrodisiac. Instead, females may use sperm as a cue for post-copulatory mate assessment and seek to remate for the direct benefit of fertility insurance if they have mated with sperm-depleted males.
一妻多夫制是性冲突的一个源头，雄性常常试图限制雌性的滥交行为。因此，雄性通过抗催情剂和交配栓来操控雌性的接受能力，以防止雌性再次交配，这可能成为性冲突的一个源头。当雌性必须再次交配以确保生育能力时，这种性冲突可能会加剧。雄性红边袜带蛇会产生一个大的、凝胶状的交配栓，有人提出该交配栓有两个作用：一是从物理上防止再次交配；二是含有一种抗催情剂，可降低雌性的接受能力。由于其分离的生殖模式，这些雄性可能会精子耗尽。如果雌性与精子不足的雄性交配，并且不再接受进一步交配，那么这就代表了一种严重的冲突。我们测试了雌性与产生无精子交配栓的雄性交配后，其再次交配频率是否会受到影响。我们发现，与输精管切除的雄性交配后，雌性比与未处理的雄性交配后更有可能再次交配，尽管输精管切除的雄性仍然会产生交配栓。这些结果表明，交配栓中的射精物质不含有抗催情剂。相反，雌性可能将精子作为交配后配偶评估的一个线索，如果它们与精子耗尽的雄性交配，就会为了生育保险的直接益处而寻求再次交配。
