Department of Biology, 3258 TAMU, Texas A&M University, College Station, TX 77843, USA.
Am Nat. 2013 Sep;182(3):410-20. doi: 10.1086/671233. Epub 2013 Jul 15.
Empirical studies of sexual selection often focus on events occurring either before or after mating but rarely both and consequently may fail to discern the relative magnitudes and interactions of premating and postmating episodes of selection. Here, we simultaneously quantify premating and postmating selection in the sex-role-reversed Gulf pipefish by using a microsatellite-based analysis of parentage in experimental populations. Female pipefish exhibited an opportunity for selection (I) of 1.64, which was higher than that of males (0.35). Decompositions of I and the selection differential on body size showed that over 95% of the selection on females arose from the premating phase. We also found evidence for a trade-off between selection phases, where multiply mating females had significantly lower offspring survivorship compared to singly mated females. In males, variance in relative fitness arose mainly from the number of eggs received per copulation and a small number of males who failed to mate. Overall, our study exemplifies a general approach for the decomposition of total selection into premating and postmating phases to understand the interplay among components of natural and sexual selection that conspire to shape sexually selected traits.
性选择的实证研究通常集中于交配前后发生的事件，但很少同时关注两者，因此可能无法辨别亲代选择和交配后选择的相对幅度和相互作用。在这里，我们通过对实验种群进行基于微卫星的亲子关系分析，同时量化了性别反转的 Gulf 笛鲷的亲代选择和交配后选择。雌性笛鲷表现出 1.64 的选择机会（I），高于雄性的 0.35。I 的分解和体型大小的选择差异表明，雌性的选择超过 95%来自于交配前阶段。我们还发现了选择阶段之间存在权衡的证据，多次交配的雌性与单次交配的雌性相比，后代的存活率明显较低。在雄性中，相对适合度的方差主要来自于每次交配获得的卵子数量，以及一小部分未能交配的雄性。总的来说，我们的研究为将总选择分解为交配前和交配后阶段提供了一个范例，以了解自然选择和性选择的各个组成部分之间的相互作用，这些相互作用共同塑造了有性选择的特征。
