Dissertation Research: Patterns of Covariation in Male Traits: The Role of Predation

9701108瑞安动物物种之间和内部的许多变化是由于不同种群中自然选择强度的差异而产生的。 这一点在用于求爱和择偶的特征上尤其正确，因此受到性选择的影响。 以前的研究主要集中在单一性状上;然而，配偶选择通常是基于多个性状的组合。 自然选择对不同性状的作用方式截然不同。 本研究探讨剑尾鱼的选择与雄鱼的显着性。 雄性剑尾鱼在身体大小、尾鳍上的“剑”的表达以及求偶选择上都有很大的差异。 这种变化发生在几个组织层次上：物种之间，同一物种的种群之间，以及种群内。 初步证据表明，剑的长度协变与捕食风险在三个剑尾鱼物种。 本研究将（1）在一组密切相关的剑尾鱼中的9个物种的3个种群中检验雄性特征与捕食风险之间的关联;（2）在另一个地理分布广泛的剑尾鱼物种的10个种群中检验这些关联;（3）直接检查两个种群的一个子集中的雄性捕食;（4）被捕食风险较高的剑尾鱼种群的测试性状。 这项研究应该提供有价值的洞察力，自然和性选择的力量，如捕食和配偶选择，如何相互作用，以产生复杂的套房的显着特征的动物。

9701108 Ryan Much of the variation among and within animal species arises as a result of differences in the strength of natural selection in different populations. This is particularly true for characteristics that are used in courtship and mate choice, and are therefore subject to sexual selection. Previous studies have concentrated on single traits; however, mate choice is usually based on suites of multiple traits. Natural selection can act in dramatically different ways on different traits. This study addresses the selection, and male conspicuousness in swordtail fish. Male swordtails vary greatly in body size, in the expression of a "sword" on the caudal fin of males, and in courtship in mate choice. This variation occurs at several levels of organization: among species, among populations of the same species, and within populations. Preliminary evidence suggests that sword length covaries with predation risk in three swordtail species. This research will (1) test for associations between male traits and predation risk in three populations each of the nine species in a group of closely related swordtails; (2) test for these associations in ten populations of one other swordtail species with a wide geographic distribution; (3) directly examine male predation in a subset of populations from both groups; and (4) test characters in swordtail populations with higher predation risks. This study should provide valuable insight into how forces of natural and sexual selection, such as predation and mate choice, interact to produce complex suites of conspicuous traits in animals.