Biomechanical and Physiological Limits to Animal Flight Performance

达德利9603736 动物运动能力的内在限制还不太清楚。 对于动物运动，已知的有氧代谢率最高的是飞行形式，特别是蜂鸟和昆虫。 达德利博士将研究蜂鸟和体重相当的昆虫飞行性能的生理和生物力学限制。 实验混合气体的氧气浓度和空气密度将同时变化，以便在空气动力学和生理学上挑战盘旋的蜂鸟和飞蛾。 将通过确定这些动物不能再维持悬停飞行的空气密度和氧气浓度，从行为上评估飞行性能的极限。 氧气消耗的同时测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振运动学，以估计相关的飞行肌肉的机械功率的支出。 一个额外的一系列的实验，然后将实施，提供增强的氧气可用性在相同的空气密度，以测试的假设，扩散的氧通量是这两个类群的最大有氧性能的限制步骤。 在这种条件下，氧消耗率的增加表明扩散约束限制了最大运动性能，而没有这种增加将表明呼吸系统内的对流通量的限制，或飞行力学的生物力学约束。 零假设预测，飞蛾的气管呼吸将最终受到氧气供应的限制，而蜂鸟的肺通气将显示没有这样的能量增强的条件下，增加氧气供应。 更一般地说，这项研究将证明在最大性能的条件下，脊椎动物和昆虫呼吸系统的固有设计约束。

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.