DISSERTATION RESEARCH: Hermaphroditic Strategies in the Opisthobranch Gastropod, Aplysia Californica

雌雄同体现象在无脊椎动物中很普遍，如淡水蜗牛、扁形虫和藤壶。令人惊讶的是，人们对雌雄同体的生殖策略知之甚少。雌雄同体物种是指个体同时具有雄性和雌性生殖系统，并且可以以任何一种角色交配的物种。pi不理解在男性和女性角色之间投资能量的战略权衡，这使得个体能够最佳地繁殖，即在其一生中产生最多可能的后代。对海蛞蝓的初步研究表明，体型是交配策略的一个重要决定因素：大型动物比小型动物更倾向于充当雌性。本研究将建立一个数学模型来预测不同体型的雌雄同体储存精子的最佳繁殖策略。该模型的预测将通过一种常见的海蛞蝓——加利福尼亚海兔（一种蛇科腹足类动物）——在野外观察交配并进行实验室实验来进行测试。此外，基于DNA的父权分析将量化在雄性角色下交配可以产生多少后代，因为个体可以多次交配，并在产卵前储存从多个配偶处获得的精子。这个项目的发现将为理解生殖行为和生理学提供新的见解，同时揭示为什么雌雄同体在无脊椎动物中广泛存在，以及为什么几乎所有的蛇科腹足类动物，如加利福尼亚海兔，都是雌雄同体。

Hermaphroditism is widespread in invertebrates, such as freshwater snails, flatworms, and barnacles. Surprisingly little is known about hermaphroditic reproductive strategies. Hermaphroditic species are those in which individuals have both male and female reproductive systems and can mate in either role. The PIs do not understand the strategic tradeoff between investing energy in male versus female roles that allows an individual to reproduce optimally, i.e. produce the most possible offspring over its lifetime. Preliminary studies on sea slugs indicate that body size is an important determinant of mating strategies: large animals tend to function as females more than small animals. This study will develop a mathematical model to predict the best reproductive strategy for sperm-storing hermaphrodites of varying body sizes. Predictions of the model will be tested using a common sea slug, the California Sea Hare (an opisthobranch Gastropod), by observing matings in the field and conducting lab experiments. In addition, DNA based paternity analysis will quantify how many offspring can be sired by mating in the male role given that individuals can mate several times and store the sperm received from several mates before egg-laying.The findings of this project will provide new insights into the understanding of reproductive behavior and physiology, along with shedding light on why hermaphroditism is widespread in invertebrates, and also why nearly all opisthobranch Gastropods, like the California Sea hare, are hermaphrodites.