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

在过去的几十年里，关于性选择的研究呈指数级增长，是进化生物学的一个主要研究主题。交配前的性选择（通常是雄性-雄性竞争和雌性配偶选择）和交配后的性选择（精子竞争和隐性雌性选择，如非随机受精）已经独立发展了很长一段时间。近年来，人们可以看到一个明显的趋势，在整合两个层次的性选择。然而，在交配后性选择中仍然有一些模糊的话题，如精子设计中的功能变异。此外，有几个模型系统中，这两个级别的性选择进行了详细研究。最后，我们对精子性状的进化能力的认识还存在空白。关于鱼类遗传变异和协变的数据是完全缺乏的。在我们的建议中，我们希望促进交配后的性选择在三棘鱼，Gasterosteus aculeatus，这是很好的研究交配前的性选择的研究。在这种外部受精的鱼类中，潜行和精子竞争是很常见的。近年来，我们提倡棘鱼作为交配后性选择的非常有前途的科目。我们计划测试精子的表型进化的先决条件，即，精子和睾丸性状和雄性繁殖颜色的遗传变异和共变的估计，以及特定的环境效应，如食物配给，类胡萝卜素，紫外线辐射和特定的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。体外精子竞争将研究在运动鞋和环境引起的精子设计的变化，而在受精时的神秘女性的选择将在体外研究亲属方面的延迟射精。此外，将研究射精特征与女性吸引力、女性相关性和精子老化的关系。第三个目标将着眼于精子竞争的长期后果，通过比较精子和睾丸之间的不同物种的棘鱼家庭，Gasterosteidae，和不同种群的三棘鱼。

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.