Body size dependence of metabolic rate, body surface and scale morphology complicate disentangling the contribution of these characteristics to adaptive changes in total evaporative water loss (TEWL) of reptiles. To separate adaptive changes from size-related dependence, we compared intra- and interspecific scaling of several candidate traits in eyelid geckos (Eublepharidae), a group exhibiting large variation in body size and TEWL. The intraspecific allometry of TEWL of a eublepharid species fits the geometric surface-mass relationship. However, evolutionary shifts to both higher and lower evaporation were strongly correlated with habitat aridity and cannot be explained by shifts in body size alone. The intraspecific allometry of standard metabolic rate is nearly the same as the interspecific allometry. Unlike for mammals and birds, this pattern rules out respiratory water loss as a driver of the adaptive changes in TEWL among eublepharids. Scale morphology was independent of TEWL variation as well, but the correlation between cutaneous water loss and TEWL suggests a crucial role of skin permeability in adaptation to habitat aridity. Our analyses demonstrate how powerful a comparison between intra- and interspecific allometries can be for detecting body size-dependent mechanisms of adaptive changes in ecophysiological traits correlated with body size.

中文翻译：

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壁虎蒸发失水的个体发育、系统发育和适应性变化机制。

代谢率、体表和鳞片形态的体型依赖性使这些特征对爬行动物总蒸发失水 (TEWL) 适应性变化的贡献复杂化。为了将适应性变化与大小相关的依赖性分开，我们比较了眼睑壁虎（Eublepharidae）中几种候选特征的种内和种间缩放，该组在体型和 TEWL 方面表现出很大的变化。eublepharid 物种的 TEWL 的种内异速生长符合几何表面质量关系。然而，向更高和更低蒸发量的进化转变与栖息地干旱密切相关，不能仅用体型变化来解释。标准代谢率的种内异速生长与种间异速生长几乎相同。与哺乳动物和鸟类不同，这种模式排除了呼吸性水分流失是 eublepharids 中 TEWL 适应性变化的驱动因素。鳞片形态也与 TEWL 的变化无关，但皮肤水分流失与 TEWL 之间的相关性表明皮肤渗透性在适应栖息地干旱方面起着至关重要的作用。我们的分析表明，种内和种间异变之间的比较对于检测与体型相关的生态生理特征适应性变化的体型依赖性机制有多么强大。