Post-copulatory intra- and intersexual selection at fertilization in a polygamous fish

在过去的几十年里，对性选择的研究呈指数增长，是进化生物学的一个重要研究主题。交配前的性选择（通常是雄性竞争和雌性择偶）和交配后的性选择（精子竞争和非随机受精等隐性雌性选择）的研究已经独立发展了很长时间。近年来，人们可以看到一种明显的趋势，即把两种层次的性选择结合起来。然而，在交配后的性选择中，仍然有一些模棱两可的话题，比如精子设计的功能变异。此外，很少有模型系统详细研究这两个层次的性选择。最后，我们对精子特征的可进化性的认识还存在空白。关于鱼类的遗传变异和共变异的数据完全缺乏。在我们的提案中，我们希望促进对三棘棘鱼交配后性选择的研究，Gasterosteus aculeatus，在交配前性选择方面已经得到了很好的研究。潜行，因此精子竞争在这种外部受精的鱼类中很常见。近年来，我们主张棘鱼作为交配后性选择的非常有前途的对象。我们计划测试精子表型进化的先决条件，即估计精子和睾丸性状和雄性繁殖颜色的遗传变异和共变异，以及特定的环境效应，如食物定量、类胡萝卜素、紫外线辐射和特定寄生虫对精子性状和相关功能的影响。第二个目标涉及受精水平上的性内和性间选择。体外精子竞争将在运动鞋延迟射精和环境诱导的精子设计变化方面进行研究，而受精时女性的隐秘性选择将在体外就亲属进行研究。此外，射精特征将被研究与女性吸引力、女性亲缘关系和精子老化的关系。第三个目标是通过比较刺鱼科（刺鱼科）的不同物种和三刺鱼的不同种群之间的精子和睾丸，来研究精子竞争的长期后果。

In the past decades, studies on sexual selection have increased exponentially and are a major research theme in Evolutionary Biology. Work on pre-copulatory sexual selection (usually male-male competition and female mate choice) and post-copulatory sexual selection (sperm competition and cryptic female choice like non-random fertilization) have developed independently for a long time. In recent years, one can see a clear trend in integrating the two levels of sexual selection. There are, however, still several ambiguous topics in post-copulatory sexual selection like functional variation in sperm design. Moreover, there are few model systems in which both levels of sexual selection are studied in detail. Finally, there is a gap in our knowledge about the evolvability of sperm traits. Data on genetic variation and covariation are lacking altogether in fish. In our proposal we want to promote the study of post-copulatory sexual selection in three-spined sticklebacks, Gasterosteus aculeatus, which is well-studied with respect to pre-copulatory sexual selection. Sneaking, and thus sperm competition is common in this fish species with external fertilization. In recent years we have advocated sticklebacks as very promising subjects for post-copulatory sexual selection. We plan to test the prerequisites for phenotypic evolution of sperm, that is, the estimation of genetic variation and covariation of sperm and testes traits and male breeding coloration as well as specific environmental effects like the influence of food ration, carotenoids, ultraviolet radiation, and specific parasites on sperm traits and associated function. The second aim concerns intra- and intersexual selection at the level of fertilization. In vitro sperm competition will be studied with respect to delayed ejaculation in sneakers and environmentally induced changes in sperm design, whereas cryptic female choice at fertilization will be studied in vitro with respect to kin. Additionally, ejaculate characteristics will be studied in relation to female attractiveness, female relatedness, and sperm aging. The third aim will look at long-term consequences of sperm competition by comparing sperm and testes among the different species of the stickleback family, the Gasterosteidae, and among various populations of the three-spined stickleback.