Dhole Sumit, Servedio Maria R
Department of Biology, University of North Carolina, CB-3280, Coker Hall, Chapel Hill, North Carolina, 27599-3280.
Evolution. 2014 Oct;68(10):3008-19. doi: 10.1111/evo.12477. Epub 2014 Aug 12.
Male ejaculates include large amounts of seminal fluid proteins (Sfps) that influence male sperm competitive success. In spite of their diverse proximate functions, Sfps involved in sperm competition increase male fitness in one of three ways: (1) "avoidance" proteins help males avoid sperm competition, (2) "defense" proteins help males defend their sperm from displacement by the female's subsequent mate, and (3) "offense" proteins aid males in displacing sperm of preceding males. Here, we present a population genetic model of the evolution of allocation of finite resources by males to the three kinds of Sfps. We analyze the influence of relative efficiencies of different Sfps, of plasticity in resource allocation, and of differences in viability costs of Sfps. We find that in absence of plasticity or different viability costs, equal investment in defense and offense Sfps evolves, irrespective of their relative efficiency. In all cases, males evolve to invest more in avoidance when avoidance proteins are increasingly efficient, and when offense is more efficient than defense. Differences in viability costs result in lower investment in costly proteins, whereas plasticity has complex effects, influencing both the optimal seminal fluid composition and maintenance of variation in investment in these proteins across populations.
男性射精中包含大量影响男性精子竞争成功的精液蛋白（Sfps）。尽管这些精液蛋白具有多种直接功能，但参与精子竞争的精液蛋白通过以下三种方式之一提高男性的适应性：（1）“回避”蛋白帮助男性避免精子竞争，（2）“防御”蛋白帮助男性保护自己的精子不被雌性的后续配偶取代，（3）“进攻”蛋白帮助男性取代先前雄性的精子。在此，我们提出了一个种群遗传模型，用于研究雄性将有限资源分配给这三种精液蛋白的进化过程。我们分析了不同精液蛋白的相对效率、资源分配的可塑性以及精液蛋白生存成本差异的影响。我们发现，在没有可塑性或不同生存成本的情况下，无论防御性和进攻性精液蛋白的相对效率如何，都会进化出对它们的均等投资。在所有情况下，当回避蛋白效率越来越高以及进攻比防御更有效时，雄性会进化出对回避的更多投资。生存成本的差异导致对成本较高的蛋白投资减少，而可塑性具有复杂的影响，既影响精液的最佳组成，也影响这些蛋白在种群中投资变异的维持。
