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。这个项目将研究日本冲浪鱼Ditrema temminck ii的性选择和繁殖是如何变化的，并将交配和后代数量的变化与东太平洋海岸特有的其他冲浪鱼进行比较。这个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亚成年状态的怀孕。这项研究将在大阪市立大学和新泻大学与阿瓦田聪博士合作进行。这一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别选择是如何变化的，这些物种在大约700万年前分化，并保持着独特的生殖策略。该项目将通过利用微卫星将怀孕的泰明克龙虾幼崽的亲子关系分配给雌性泰明克龙虾来测量雌性泰明克龙虾的性别选择。将确定父鱼数量和后代数量(贝特曼梯度)之间的相关性，并将其与杀虫科其他种类的冲浪鱼进行比较。此外，在狄姆明克二世观察到了精子储存，这使得这个项目具有独特的地位，以解决对女性贝特曼梯度研究的一个常见批评：即父亲的数量低估了实际的配偶数量。通过逐步跟踪繁殖季节的配偶数量，并与检测到的雄蜂数量进行比较，这项研究将是此类研究中第一次有权验证(或拒绝)使用雄蜂作为总体配偶数量的估计。因此，这个项目旨在洞察一种表现出派生生殖策略的鱼类家族中雌性性别选择的进化；通过这样做，我们也可能解决围绕使用雄性作为配偶数量替代品的争议，并为未来冲浪中雌性贝特曼梯度研究扫清道路。该奖项由东亚和太平洋夏季研究所计划设立，支持一名美国研究生的夏季研究，并由美国国家科学基金会和日本科学促进会共同资助。

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.