Biomechanical and Physiological Limits to Animal Flight Performance

达德利9603736对运动成绩和动物的运动能力的内在限制知之甚少。一般来说，在动物的运动中，已知的有氧代谢率最高的是飞行状态，特别是蜂鸟和昆虫。达德利博士将在蜂鸟和体重相当的昆虫身上研究飞行性能的生理和生物力学极限。实验混合气体的氧气浓度和空气密度将同时变化，以在空气动力学和生理上挑战盘旋的蜂鸟和飞蛾。飞行性能的极限将通过确定这些动物不能再维持盘旋飞行的空气密度和氧气浓度来进行行为评估。同时测量耗氧量将评估相关的最大代谢率，而空气动力学模型将应用于观察到的翼拍运动学，以估计飞行肌肉相关的机械动力消耗。然后，将实施一系列额外的实验，在相同的空气密度下提供更高的氧气利用率，以检验扩散氧通量是这两个分类群最大有氧性能的限制步骤的假设。在这种情况下，氧气消耗率的增加将表明扩散限制限制了最大运动能力，而不是这种增加将意味着呼吸系统内对流通量的限制，或飞行力学的生物力学限制。零假设预测，飞蛾的气管呼吸最终将受到氧气供应的限制，而蜂鸟的基于肺的呼吸在氧气供应增加的条件下不会表现出这样的能量增强。更广泛地说，这项研究将展示脊椎动物和昆虫呼吸系统在最大性能条件下的内在设计限制。

Dudley 9603736 Inherent limits to exercise performance an athletic capacity of animals are little-understood. For animal locomotion generally, the highest known rates of aerobic metabolism are found in flying forms, particularly among hummingbirds and insects. Dr. Dudley will examine the physiological and biomechanical limits to flight performance in hummingbirds and in insects of comparable body mass. Oxygen concentration and air density of experimental gas mixtures will be simultaneously variesd so as to aerodynamically and physiologically challenge hovering hummingbirds and moths. The limits to flight performance will be evaluated behaviorally by determining the air densities and oxygen concentration at which these animals can no longer sustain hovering flight. Simultaneous measurements of oxygen consumption will evaluate the associated maximal metabolic rates, while aerodynamic models will be applied to the observed wingbeat kinematics to estimate the associated expenditure of mechanical power by the flight muscle. An additional series of experiments will then be implemented that provide enhanced oxygen availability at equivalent air densities, so as to test the hypothesis that diffusive oxygen flux is the limiting step in maximum aerobic performance of these two taxa. Increased rates of oxygen consumption under such conditions will indicate that diffusive constraints limit maximum locomotor performance, whereas no such increase will suggest limits of convective flux within the respiratory system, or biomechanical constraints on flight mechanics. The null hypothesis predicts that the tracheal respiration of moths will ultimately be limited by oxygen availability, whereas the pulmonary-based ventilation of hummingbirds will show no such energetic enhancement under conditions of increased oxygen availaility. More generally, this research will demonstrate inherent design constraints of both vertebrate and insect resporatory systems under conditions of maximum performance.