Evolution of Coloration and Mate Preferences Along Environmental Gradients

一些近亲物种之间繁殖的唯一障碍是雌性的择偶偏好。导致雌性配偶偏好的因素，或者它们所基于的雄性特征的进化（即，世代变化）可能导致新物种的形成。科学家们刚刚开始了解环境在这一过程中的作用。孔雀鱼是一种原产于特立尼达的小型溪流鱼类，雌性更喜欢有更大、更亮的橙色斑点的雄性。橙色斑点含有两种色素，一种是雄性可以合成的（果蝇素），另一种必须从食物中获取（类胡萝卜素）。对孔雀鱼来说，类胡萝卜素的主要来源是生长在溪流中的岩石上的藻类。更宽的溪流在森林树冠上形成更大的缝隙，因此接收到更多的阳光，生长出更多的藻类。该项目将研究森林冠层覆盖的变化如何影响雄性颜色和雌性配偶偏好的进化。方法包括田间实验、实验室育种实验、颜色测量和生化分析。更广泛的目标是更深入地了解环境是如何影响择偶偏好及其偏好特征的进化的。这项研究将有助于我们对生物多样性的认识。

The only barriers to reproduction between some closely related species are female mate preferences. Factors that cause female mate preferences, or the characteristics of males they are based on, to evolve (i.e., change over generations) can lead to the formation of new species. Scientists are just beginning to understand the role of the environment in this process. In guppies, a small stream-dwelling fish native to Trinidad, females prefer males with larger and "brighter" orange spots. The orange spots contain two types of pigments, one of which males can synthesize (drosopterins) and the other of which they must obtain from their food (carotenoids). The main source of carotenoids for guppies is algae, which grow on rocks in the stream. Wider streams make larger gaps in the forest canopy, and consequently receive more sunlight and have larger standing crops of algae. This project will examine how variation among streams in forest canopy cover affects the evolution of male coloration and female mate preferences. The methods will include field experiments, laboratory breeding experiments, color measurements, and biochemical analyses.The broader goal is to develop a deeper understanding of how the environment affects the evolution of mate preferences and the traits they favor. This study will contribute to our knowledge of biological diversity.