Evolution of Coloration and Mate Preferences Along Resource Availability Gradients

颜色和配偶偏好的进化沿着资源可用性梯度格雷戈里·弗兰克·格雷瑟（PI）吉塔·拉曼·科卢鲁（co-P）在一些密切相关的物种之间，繁殖的唯一障碍是雌性配偶对雄性第二性征的偏好。 导致女性择偶偏好进化的因素（即，（3）物种的进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。孔雀鱼是特立尼达岛的一种小型溪流鱼类，雌性孔雀鱼更喜欢有较大且“明亮”的橙子斑点的雄性。橙子斑点含有两种色素，一种是雄性可以合成的（drosopterins），另一种是它们必须摄取的（carotenoids）。孔雀鱼从生长在河床岩石上的藻类中获取类胡萝卜素。藻类对孔雀鱼的可用性受到森林冠层覆盖的强烈影响，因此受到河流宽度的影响（更宽的河流在森林中产生更大的间隙）。拟议的项目将扩大和加强努力，以了解森林冠层覆盖的溪流之间的变化如何影响男性色彩和女性择偶偏好的演变。此外，将进行新的实验，以确定（1）类胡萝卜素的消费是否影响寄生虫的抵抗力，（2）类胡萝卜素从母亲转移到后代是否影响后代的生存能力，（3）男性是否也表达基于类胡萝卜素的配偶偏好。这些方法将包括田间试验、实验室育种试验、颜色测量和生化分析。更广泛的目标是更深入地了解环境如何影响配偶偏好的进化以及他们喜欢的特征。这项研究将有助于我们了解生物多样性。

Evolution of coloration and mate preferences along resource availability gradientsGregory Frank Grether (PI)Gita Raman Kolluru (co-P)The only barriers to reproduction between some closely related species are female mate preferences for male secondary sexual characters. Factors that cause female mate preferences 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 which males can synthesize (drosopterins) and another which they must ingest (carotenoids). Guppies acquire carotenoids from algae, which grow on rocks in the streambed. Algae availability for guppies is strongly influenced by forest canopy cover and therefore by stream width (wider streams create larger gaps in the forest). The proposed project will expand and strengthen efforts to understand how variation among streams in forest canopy cover affects the evolution of male coloration and female mate preferences. In addition, new experiments will be carried out to determine (1) whether carotenoid consumption influences parasite resistance, (2) whether transfer of carotenoids from mothers to offspring affects offspring viability, and (3) whether males also express carotenoid-based 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.