DISSERTATION RESEARCH: Comparative Analysis of the Costs of Sexually Selected Traits within Swordtails and Platyfish

小西奥多·加兰德和Christopher E.OufieroProposal#0709788剑尾和鸭嘴鱼性别选择特征的成本比较分析通过自然选择，生物通常变得更好地适应每一代人的环境条件。然而，由于自然选择的结果，一些特征很难解释。例如，雄性孔雀又长又艳丽的尾巴似乎会阻碍它们的飞行能力，并吸引捕食者的注意。此外，这种精心制作的尾巴的种植和维护成本可能很高，将稀缺的能量资源从其他需求中转移出来。因此，查尔斯·达尔文提出了性选择理论，该理论认为，雄性孔雀尾巴等特征的进化可能是因为它们帮助携带者获得配偶，即使它们在某种程度上也损害了它们必须做的其他事情。这项研究将研究与一种广为人知的性选择特征有关的成本和潜在的补偿机制，这种特征是雄性剑尾和扇贝(剑鱼属)在几个物种中表现出的“剑”。剑有可能通过增加阻力或生理负担来降低运动能力。将测试几项运动性能，包括短跑速度和游泳耐力。此外，还将检查潜在的代偿特征，如心脏质量和最大耗氧量。如果不考虑这些特征，这些特征可能会掩盖性别选择特征对运动能力的负面影响。这项研究将极大地促进我们对性选择代价的理解。这将是第一次对成本和可能的补偿机制进行多物种比较研究。它还将进一步阐明一种新的脊椎动物系统中结构和性能之间的关系。这将使面向生物医学的本科生助理能够更广泛地了解和欣赏动物行为和生物生物学，以及这些如何与解剖学和生理学相结合。

Theodore Garland, Jr. and Christopher E. OufieroProposal # 0709788Comparative analysis of the costs of sexually selected traits within swordtails and platyfish.Through natural selection, organisms generally become better adapted to their environmental circumstances with each passing generation. However, some traits are difficult to explain as a result of natural selection. For example, the long and gaudy tails of male peacocks would seem likely to hinder their flying abilities and to attract the attention of predators. Moreover, such elaborate tails are probably expensive to grow and maintain, diverting scarce energetic resources away from other needs. Therefore, Charles Darwin proposed the theory of sexual selection, the idea that such traits as male peacock tails might evolve because they helped their bearers to obtain mates, even if they also compromised, to some extent, other things they had to do. This research will examine costs and potential compensatory mechanisms related to a well-described sexually selected trait, the "sword" exhibited by males in several species of swordtail and platyfish (genus Xiphophorus). The sword has the potential to reduce locomotor abilities through an increase in drag or physiological burden. Several locomotor performances will be examined, including sprint speed and swimming endurance. Additionally, potential compensatory traits, such as heart mass and maximum oxygen consumption, will be examined. When not taken into account, these traits may mask the negative effect of the sexually selected trait on locomotor performance. This research will significantly advance our understanding of the costs of sexual selection. It will be the first multi-species comparative study to examine both costs and possible compensatory mechanisms. It will also further elucidate the relations between structure and performance in a novel vertebrate system. This will enable biomedically oriented undergraduate assistants to gain a broader understanding of, and appreciation for, animal behavior and organismal biology, and how these integrate with anatomy and physiology.