RUI: The Relationship between Gamete Production and Reproductive Success

9416548云德计划摘要本研究将探讨种群密度对群体海鞘中配子产生和繁殖成功之间关系的影响。先前的研究发现，种群密度的变化会在雄性和雌性阶段群体中不同地影响配子生产和生殖成功之间的关系。在竞争的情况下(高种群密度)，产量与群体获得的受精数量之间的关系是线性的，但在非竞争的情况下(低种群密度)，在雄配子生产水平上处于平台期，这使得雄性能够使其附近的所有卵受精。相反，在低种群密度下(雄配子限制受精卵的数量)，产卵量与集群产生的后代数量之间预计是线性的，但在高种群密度时，由于集群可以孵化的胚胎数量的限制，产卵量和后代数量之间的关系是稳定的。在这项研究项目中，将通过建立在两种密度条件下配子产量不同的海鞘实验种群，并分析雄性和雌性繁殖成功来检验这些假说。雄性繁殖成功将通过等位酶标记来分配父权，而雌性生殖成功将通过直接统计每窝受精卵的比例来进行。这项研究将通过考察受精过程对配子分配模式施加的选择压力，有助于我们对底栖海洋生物的了解。

9416548 Yund PROJECT ABSTRACT This proposal will explore the impact of population density on the relationship between gamete production and reproductive success in a colonial ascidian. Previous research has found that variation in population density will affect the relationship between gamete production and reproductive success differently in male and female-phase colonies. The relationship between production and the number of fertilization obtained by a colony is expected to be linear in competitive situations (high population densities), but plateau in noncompetitive situations (low population densities) at the male gamete production level that allows a male to fertilize all of the eggs in his vicinity. In contrast, the relationship between egg production and the number of offspring produced by a colony is expected to be linear at low population densities (where male gamete limit the number of eggs fertilized), but plateau at high population densities due to constraints on the number of embryos that colonies can brood. These hypotheses will be tested in this research project by establishing experimental populations of ascidians that vary in gamete production under two density conditions and assaying male and female reproductive success. Male reproductive success will be assayed by using allozyme markers to assign paternity, while female reproductive success will be assayed by directly counting the proportion of eggs fertilized in each brood . This study will contribute to our knowledge of benthic marine organisms by examining the selective pressures that fertilization processes can exert on gamete allocation patterns.