Dissertation Research: Metabolic Correlates of Hylid Locomotor Performance and Acoustic Response

当前生态生理学的一个假说认为，动物物种在运动生理方面的差异是对维持行为能力的自然选择的反应。通常经历高水平持续行为的动物被认为具有高有氧能量生产能力，而低有氧能力的动物被认为只能维持低强度的行为，必须依靠无氧代谢来促进更高水平的活动，这是不可持续的。例如，无尾两栖动物在活动代谢方面的物种差异与运动、觅食、捕食者躲避和呼叫行为的差异有关。以前的研究没有区分适应性假说（即行为和生理上的新近选择）和生理差异的替代假说，如体型的差异、生理与某些未被研究的性状的相关性或系统发育施加的约束。拟议中的研究将测试一组密切相关的物种——北美树蛙的生理-行为相关性。生理变异的适应性意义将通过确定由系统发育和体型引起的变异的比例，以及归因于已经证明或引证对生存和繁殖有影响的几个变量（例如，运动表现和呼唤行为）的变异的比例来评估。在去除体型和系统发育的影响后仍然存在的相关性将被认为是最近选择的结果。

A current hypothesis in ecological physiology states that differences among animal species in the physiology of exercise arose in response to natural selection on the capacity to sustain behavior. Animals that typically undergo high levels of sustained behavior are expected to have high capacities for aerobic energy production, whereas animals with low aerobic capacities are expected to sustain only low intensity behaviors and must rely on anaerobic metabolism to fuel higher levels of activity, which are not sustainable. For example, species differences in activity metabolism among anuran amphibians have been related to differences in locomotor, foraging, predator avoidance, and calling behavior. Previous studies did not distinguish among adaptive hypotheses (i.e. recent selection on behavior and physiology) and alternative hypotheses for differences in physiology, such as differences in body size, correlation of physiology with some unexamined trait, or constraints imposed by phylogeny. The proposed research will test for physiology-behavior correlations in a group of closely related species, the North American treefrogs. The adaptive significance of variation in physiology will be assessed by determining the fraction of variation due to phylogeny and body size and the fraction attributable to variation in several variables that have demonstrated or adduced effects on survival and reproduction (e.g., locomotor performance and calling behavior). Correlations that persist after removing the effects of body size and phylogeny will be deemed to represent the results of recent selection.