McGuire Jimmy A, Dudley Robert
Museum of Vertebrate Zoology, University of California, Berkeley, California 94720, USA.
Am Nat. 2005 Jul;166(1):93-106. doi: 10.1086/430725. Epub 2005 May 2.
Despite exhibiting considerable interspecific variation in body mass, flying lizards of the genus Draco are isometric in their area-mass scaling relationships and exhibit no significant compensatory variation in wing aspect ratio. Thus, larger species are expected to be relatively poor gliders, in lieu of behavioral or physiological compensation, when compared with smaller congeners. Here we tested this hypothesis by conducting gliding performance trials for 11 Draco species spanning virtually the entire size range of the genus. We considered three primary performance variables: maximum velocity adjusted for wind conditions, height lost over a standard horizontal glide distance, and glide angle. Comparative analysis confirmed that larger species are relatively poor gliders and do not compensate substantially for their higher wing loadings via either behavioral or physiological mechanisms. Flying lizards were found to exhibit substantial context-dependent variation in glide performance, with smaller species often exhibiting extensive variation in height lost and glide angle between trials. Variation also was observed in empirically derived velocity profiles, with only a subset of individuals appearing to perform equilibrium glides. Such size-dependent variation in performance has important consequences for the ecology and evolution of flying lizards and other glissant taxa.
尽管飞蜥属的飞行蜥蜴在体重上表现出相当大的种间差异，但它们在面积-质量缩放关系上呈等比缩放，且在翼展比上没有显著的补偿性变化。因此，与体型较小的同属蜥蜴相比，体型较大的物种在没有行为或生理补偿的情况下，预计是相对较差的滑翔者。在这里，我们通过对几乎涵盖该属整个体型范围的11种飞蜥进行滑翔性能试验，来检验这一假设。我们考虑了三个主要性能变量：根据风况调整后的最大速度、在标准水平滑翔距离上损失的高度以及滑翔角度。比较分析证实，体型较大的物种是相对较差的滑翔者，并且不会通过行为或生理机制对其较高的翼载荷进行实质性补偿。研究发现，飞蜥在滑翔性能上表现出显著的情境依赖性变化，体型较小的物种在不同试验之间，在高度损失和滑翔角度方面常常表现出广泛的变化。在根据经验得出的速度剖面中也观察到了变化，只有一部分个体似乎进行了平衡滑翔。这种与体型相关的性能变化对飞蜥及其他滑行类群的生态和进化具有重要影响。
