The accumulation of reproductive isolation in a diverse genus of fish (Percidae: Etheostoma)

任何特定群落的生物多样性都是通过繁殖障碍或阻止物种间杂交的因素来维持的。多种不同的繁殖障碍可能会阻止物种间的杂交，一个核心问题是这些不同障碍进化的时间顺序。理论预测，行为隔离，或由于求偶行为的差异而导致的异种交配的缺失，将是在以强烈的性选择为特征的种群中进化出的第一个生殖障碍。通过雄性求偶特征和雌性偏好的共同进化，预测雌性只会识别本物种雄性的求偶特征。很少有研究直接验证这一预测，性选择在物种起源中起主要作用的证据在很大程度上仍然是间接的。达特鱼是一种色彩丰富的北美淡水鱼，具有多样化和高度夸张的雄性求爱信号，该项目量化了不同生殖障碍的相对进化速度和测试，特别是行为隔离是否进化得最早。这一结果将为性选择通过雄性信号和雌性偏好的共同进化驱动物种起源这一基本假设提供为数不多的直接检验之一。培训来自未被充分代表的高等生物学群体的本科生和研究生是该项目不可或缺的一部分。结果还将提交给地区中学，特别是少数民族和贫困学生比例较高的学校。

Biological diversity in any given community is maintained by reproductive barriers, or factors that prevent interbreeding between species. Multiple, distinct reproductive barriers may prevent interbreeding between species and a central question concerns the chronological order in which these different barriers evolve. Theory predicts that behavioral isolation, or the absence of interbreeding due to differences in courtship behavior, will be the first reproductive barrier to evolve among populations characterized by the strong action of sexual selection. Through the co-evolution of male courtship traits and female preferences, females are predicted to recognize only the courtship traits of males of their own species. Few studies test this prediction directly and evidence that sexual selection plays a primary role in the origin of species remains largely indirect. Darters are a colorful group of North American freshwater fish with diverse and highly exaggerated male courtship signals and this project quantifies the relative rates of evolution of different reproductive barriers and tests, in particular, whether behavioral isolation evolves earliest. Results will provide one of the few direct tests of the fundamental hypothesis that sexual selection drives the origin of species through the co-evolution of male signals and female preferences. Training of undergraduate and graduate students from groups underrepresented in advanced biology is integral to the project. Results will also be presented to area secondary schools, specifically targeting schools with a high representation of minorities and underprivileged students.