EAPSI: Investigating the Presence of a Female Bateman Gradient in the Japanese surfperch Ditrema Temminckii

性选择是推动进化的主要力量。该项目将研究日本冲浪鲈（Ditrema temminckii）的性选择和繁殖是如何变化的，并将其配偶和后代数量的变化与东太平洋沿岸特有的其他冲浪鲈进行比较。该项目将利用遗传信息来了解一种独特的鱼的配偶和父亲的数量，这种鱼表现出内部受精和怀孕到亚成虫状态。这项研究将在大阪市大学和新泻大学与Satoshi Awata博士合作进行。这项合作将提供独特的数据和新的见解，以了解不同物种之间的性选择是如何变化的，这些物种大约在700万年前分化，并保持了独特的生殖策略。本项目将通过利用微型卫星对怀孕的雌性特明奇鱼进行亲子鉴定，来测量雌性特明奇鱼的性选择。将确定后代数量与后代数量（贝特曼梯度）之间的相关性，并将其与其他种类的Embiotocidae科鲈鱼进行比较。此外，在D.temminckii中观察到精子储存，这使该项目独特地解决了对女性贝特曼梯度研究的普遍批评：即，配偶的数量低估了实际伴侣的数量。通过在繁殖季节逐步跟踪配偶的数量，并与检测到的性别数量进行比较，这项研究将是同类研究中第一个有能力验证（或拒绝）使用性别来估计配偶总数的研究。因此，该项目旨在深入了解鱼类家族中表现出衍生生殖策略的雌性性选择的进化；通过这样做，我们也可以解决围绕使用性别作为配偶数量的代理的争议，并为未来的雌性贝特曼梯度研究扫清道路。该奖项属于东亚和太平洋暑期研究所项目，由美国国家科学基金会和日本科学促进会共同资助，支持一名美国研究生进行暑期研究。

Sexual selection is a major force driving evolution. This project will examine how sexual selection and reproduction vary in the Japanese surfperch, Ditrema temminckii, and compare the variation in number of mates and offspring to other surfperches endemic to the eastern Pacific coast. This project will utilize genetic information to understand the number of mates and fathers in a unique fish that exhibits internal fertilization and gestation to the sub-adult state. The research will be conducted at Osaka City University and Niigata University in collaboration with Dr. Satoshi Awata. This collaboration will provide unique data and new insights into how sexual selection varies between different species which diverged roughly 7 million years ago and have maintained a unique reproductive strategy.This project will measure sexual selection in female Ditrema temminckii by utilizing microsatellites to assign parentage to broods of pregnant female D. temminckii. The correlation between the number of sires and number of offspring (Bateman Gradient) will be determined and compared to other species of surfperch in the family Embiotocidae. In addition, sperm storage has been observed in D.temminckii, which uniquely positions this project to address a common criticism of female Bateman gradient studies: namely, that the number of sires is an underestimate of the actual number of mates. By tracking the number of mates progressively during the reproductive season and comparing to the number of sires detected, this study will be the first of its kind with the power to validate (or reject) the use of sires as an estimate of the number of overall mates. Therefore, this project aims to provide insight into the evolution of female sexual selection within a family of fishes that exhibit a derived reproductive strategy; by doing so, we may also resolve the controversy surrounding the use of sires as a proxy for the number of mates and clear the way for future female Bateman gradient studies in surfperch.This award, under the East Asia and Pacific Summer Institutes program, supports summer research by a U.S. graduate student and is jointly funded by National Science Foundation and the Japan Society for the Promotion of Science.