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

Theodore Garland, Jr.和Christopher E. oufier提案# 0709788剑尾鱼和platyfish的性选择特征的成本比较分析。通过自然选择，生物每一代都能更好地适应环境。然而，由于自然选择的结果，有些特征很难解释。例如，雄孔雀的长而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，这种精心设计的尾巴很可能是昂贵的生长和维护，从其他需求转移了稀缺的能源资源。因此，查尔斯·达尔文提出了性选择理论，他认为像雄孔雀尾巴这样的特征可能会进化，因为它们可以帮助它们的后代获得配偶，即使它们在某种程度上也会牺牲它们必须做的其他事情。本研究将探讨几种剑尾鱼和剑尾鱼（剑尾鱼属）雄性所表现出的“剑”这一描述良好的性选择特征的成本和潜在的补偿机制。剑有可能通过增加阻力或生理负担来降低运动能力。几个运动性能将被检查，包括短跑速度和游泳耐力。此外，潜在的补偿性特征，如心脏质量和最大耗氧量，将被检查。如果不考虑这些特征，这些特征可能掩盖了性选择特征对运动性能的负面影响。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。这也将进一步阐明在一个新的脊椎动物系统的结构和性能之间的关系。这将使生物医学方向的本科助理获得对动物行为和有机体生物学的更广泛的理解和欣赏，以及它们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.