Collaborative Research: Determinants of male reproductive success in natural spawns

提案OCE 0117623PI - Paul Rawson，缅因州大学标题：合作研究：自然产卵中雄性繁殖成功的决定因素。摘要：本研究旨在了解生殖生物学对殖民地海洋被囊动物Botryllus schlosseri生活史进化模式的影响。该项目将测试五种假设，这些假设可能决定雄性在这种无脊椎动物的自然产卵中繁殖成功。这五种假设旨在探讨精子释放时间、配偶亲缘性、种群密度和雄性功能分配对田间和实验种群中Botryllus受精成功的影响。先前的研究表明，受精可以产生一个有活力的胚胎存在一个狭窄的时间窗口，并且可能存在配子不相容系统。此外，受精精子通常是附近菌落的产物；菌落表现出精子产生的差异，当精子竞争发生时，高水平的精子产生只会增加局部的繁殖成功率。这些初步信息表明，雄性在自然种群中的繁殖成功是一个复杂的函数，与其他种群的生殖周期、配子相容性、精子产量和种群密度有关。拟议的研究将包括实地和实验室研究，初步工作的重点是最大限度地提高一套9个多态微卫星位点的信息产量。然后，这些遗传标记将用于测定自然产卵中的父系关系，并测试关于雄性繁殖成功决定因素的五种假设。

Proposal OCE 0117623PI - Paul Rawson, University of MaineTitle: Collaborative Research: Determinants of male reproductive success in natural spawns.Summary: This proposal is an extension of previous work aimed at understanding the effects of reproductive biology on patterns of life history evolution in a colonial marine tunicate, Botryllus schlosseri. The project will test five hypotheses about factors that may determine male reproductive success in natural spawns of this colonial invertebrate. The five hypotheses specifically aim to explore the effects of timing of sperm release, relatedness of mates, population density, and allocation to male function on fertilization success in field and experimental populations of Botryllus. Previous work has shown that there is a narrow temporal window in which fertilization can result in a viable embryo, and there may be a gametic incompatibility system. Furthermore, fertilizing sperm are generally the product of nearby colonies; colonies exhibit variation in sperm production, and high levels of sperm production only increase local reproductive success when sperm competition occurs.This preliminary information suggests that male reproductive success in natural populations is a complex function of timing relative to the reproductive cycles of other colonies, gametic compatibility, sperm production, and population density.The proposed research will consist of field and laboratory studies, with preliminary work focused to maximize the information yield of a suite of nine polymorphic microsatellite loci. These genetic markers will then be used to assay paternity in natural spawns and test the series of five hypotheses about the determinants of male reproductive success.