RUI: The Relationship between Gamete Production and Reproductive Success

摘要本研究旨在探讨种群密度对海鞘种群配子产量与繁殖成功之间关系的影响。以往的研究发现，种群密度的变化对雄性和雌性种群配子产量和繁殖成功率的影响是不同的。在竞争情况下（高种群密度），产量与群体获得的受精数量之间的关系预计是线性的，但在非竞争情况下（低种群密度），在雄性配子产量水平上，雄性可以使其附近的所有卵子受精。相比之下，在低种群密度下（雄性配子限制受精卵的数量），一个种群的产蛋量和后代数量之间的关系预计是线性的，但在高种群密度下，由于种群可以孵化的胚胎数量受到限制，这种关系趋于平稳。这些假设将在本研究项目中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，并分析雄性和雌性的繁殖成功率来验证。雄性的繁殖成功将通过使用同工酶标记来确定父系关系，而雌性的繁殖成功将通过直接计数每窝受精卵的比例来测定。本研究通过考察受精过程对配子分配模式施加的选择压力，将有助于我们对底栖海洋生物的认识。

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.