Evolution of Reproductive Isolation in Cyprinodon

了解物种产生和维持的过程是现代生物学的基本目标。拟议的研究将检查行为，生态和后代适合度在限制本地濒危物种科曼奇泉幼鱼和外来物种羊头鲦鱼之间的杂交中的作用。这两个物种在地理上是隔离的，但最近由于人类活动而发生了身体接触。拟议的研究旨在确定限制两个物种个体之间交配的生殖障碍，并影响杂交后代的生存能力和生育力。繁殖障碍的强度将通过观察科曼奇斯普林斯小鱼、羊头鲦鱼和它们在人工池塘中的杂交后代之间的交配来确定。科曼奇斯普林斯小鱼、羊头鲦鱼和杂交雌鱼的偏好将通过检查雌鱼对同时呈现的每种雄性鱼的视觉和嗅觉线索的反应来测试。雄性之间的相互作用也将被观察到，以确定雄性交配行为或竞争能力的物种特异性差异。杂种的生存能力将通过比较种内和种间交配产生的后代数量来确定，然后在标准化条件下饲养后代，比较生长速度、死亡率和性别比例。本研究结果将有助于阐明北美淡水鱼系间分化的机制，并有助于了解其对杂交的抗性或易感性。该项目将有助于培训研究生和本科生，并通过海报和展览向公众宣传。学生将接受概念方法以及实验和现场方法的培训。调查结果将在区域和国家会议的海报和演讲中提出，并将在专业期刊和非专业出版物上发表。

PROJECT SUMMARYEvolution of reproductive isolation in Cyprinodon Astrid Kodric-BrownUnderstanding processes that create and maintain species is a fundamental goal of modern biology. The proposed research will examine the roles of behavior, ecology, and offspring fitness in limiting hybridization between a native, endangered species, the Comanche Springs pupfish and an exotic species, the sheepshead minnow. The two species were geographically isolated, but have recently been brought into physical contact due to human activities. The proposed research seeks to identify the reproductive barriers that limit matings between individuals of the two species, and affect the viability and fertility of hybrid offspring. The strength of reproductive barriers will be determined by observing matings between Comanche Springs pupfish, sheepshead minnow, and their hybrids in artificial ponds. Preferences of Comanche Springs pupfish, sheepshead minnow and hybrid females will be tested by examining the responses of females to simultaneous presentations of visual and olfactory cues from each type of male. Male-male interactions will also be observed to determine species-specific differences in male mating behavior or competitive ability. The viability of hybrids will be determined by comparing the number of offspring produced by intraspecific and interspecific matings, then rearing the offspring under standardized conditions to compare growth rates, mortality, and sex ratio.The results of the proposed study will elucidate mechanisms that promote the divergence between lineages and contribute to understanding the resistance or susceptibility to hybridization in North American freshwater fishes. The project will contribute to training of graduate and undergraduate students and to informing the general public through posters and exhibits. Students will receive training in conceptual approaches as well as in experimental and field methods. The findings will be presented in posters and talks at regional and national meetings, and will be published both in professional journals and in lay publications.