Dissertation Research: Mechanisms Maintaining Sympatric Morphological Divergence in Ilyodon Furcidens

进化生态学的一个基本目标是了解维持种群水平多样性的过程。理论模型表明，不同的自然选择和性选择之间的相互作用可以维持物种内部的多样性，最终导致物种形成。本项目旨在确定营养形态上的分化选择模式，并测试同一性状上的性选择是否也有助于种群分化。活产鱼的摄食形态各异，雄鱼具有显著的颜色变化，这与形态有关。比较分析被用来检验一种假设，即牙列和鳃耙数量的变化是由饮食专业化引起的，当与交配成功率的变化结合在一起时，就会导致种群分化。此外，配偶选择实验将确定女性的偏好，并测试分类交配维持由此产生的种群变异的假设。这项研究将提高对适应性进化的理解，特别是对局部过程如何导致进化多样化的理解。通过整合动物形态和功能、种群生物学和行为生态学等领域，本研究实证地探讨了自然选择和性选择在种群内分化中的作用。美国和墨西哥的本科生都将接受实验室和实地研究技术方面的培训，研究结果将通过出版物和网站向科学界和更广泛的社区传播。

A fundamental goal of evolutionary ecology is to understand the processes that maintain population-level diversity. Theoretical models suggest that the interaction between divergent natural selection and sexual selection can maintain within-species diversity, ultimately leading to speciation. This project seeks to identify the mode of divergent selection on trophic morphology and to test if sexual selection on the same trait also contributes to population divergence. The live-bearing fish Ilyodon furcidens vary in feeding morphology, and males have striking color variation that is correlated with morphology. Comparative analyses are used to test the hypothesis that variation in dentition and gill-raker number results from diet specialization and, when coupled with variation in mating success, causes population divergence. Additionally, mate choice experiments will identify female preferences and test the hypothesis that assortative mating maintains the resulting population variation. This research will improve understanding of adaptive evolution, particularly of how local processes lead to evolutionary diversification. By integrating the fields of animal form and function, population biology, and behavioral ecology, this work empirically explores the roles of natural and sexual selection in within-population divergence. Both U.S. and Mexican undergraduates will be trained in laboratory and field research techniques, and the results will be disseminated to the scientific and broader community via publication and a website.