CAREER: Sperm Limitation, Sperm Competition, and Sexual Selection in Free Spawning Invertebrates

由于精子数量远远超过卵子，进化生物学家一直认为精子竞争是驱动性别差异进化的选择机制；雄性受到交配机会的限制并相互竞争，而雌性则不受配偶的限制，表现出对配偶的选择。支持这些观点的证据来自于内部受精的物种或精子沉积在卵子上的物种。然而，祖先的，并且仍然普遍存在的生殖策略是将卵子和精子释放到环境中，与内部受精相比，受精的机会大大降低。在这种情况下，低密度的雄性和精子会限制雌性的繁殖成功。本课题将研究精子和卵子性状如何影响实验室和海洋中的受精率，在自然无脊椎动物种群中精子限制和精子竞争是如何常见的，以及配子竞争如何影响自由产卵海洋无脊椎动物性别差异的进化。这项工作将包括实验室和实地实验，有时会使用分子技术来更好地了解交配系统的进化。

Because sperm greatly outnumber eggs, evolutionary biologists have long thought that sperm competition is the selective mechanism driving the evolution of gender differences; males are limited by and compete for mating opportunities, while females are not limited by mates and exhibit mate choice. The evidence supporting these ideas come from species with internal fertilization or in situation where sperm are deposited on eggs. However, the ancestral, and still widespread, reproductive strategy is to release eggs and sperm into the environment where the chance of fertilization is much reduced compared to internal fertilization. Under these conditions, low densities of males and sperm can limit female reproductive success. This proposal will investigate how sperm and egg traits influence fertilization rates in the laboratory and ocean, how common sperm limitation and sperm competition are in natural invertebrate populations and how gamete competition can influence the evolution of gender differences in free spawning marine invertebrates. The work will involve laboratory and field experiments, at times using molecular techniques to better understand the evolution of mating systems.