Testing the thermal melanism hypothesis: a macrophysiological approach
Testing the thermal melanism hypothesis: a macrophysiological approach
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DOI：
10.1111/j.1365-2435.2007.01377.x
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发表时间：
2008-04-01
影响因子：
5.2
通讯作者：
Chown, S. L.
中科院分区：
文献类型：
--
作者：
Clusella-Trullas, S.;Terblanche, J. S.;Chown, S. L.
1.热黑化假说(TMH)预测，深色(低皮肤反射率)的个体在凉爽的气候中具有优势，因为他们比浅色(高反射率)的个体加热更快，达到更高的平衡温度。然而，对TMH的测试已经产生了混合支持，特别是在温带脊椎动物中。到目前为止，大多数研究都是在小空间尺度上进行的，或者使用了几个密切相关的种群或物种。因此，在这里，我们使用标准的和系统发育校正的分析，在大范围内检验日热蜥蜴物种的TMH，检验它的两个主要预测和一个推论。首先，我们测试了皮肤反射率和气候变量，如平均年温度(MAT)和全球太阳辐射在不同物种之间呈正相关的预测。其次，我们确定皮肤反射率和身体质量之间是否存在正相关关系。第三，由于生理、行为和形态应该是共同适应的，我们检验了皮肤反射率与热生物学特征正相关的预测。我们发现，即使在对系统发育进行调整后，皮肤反射率与年平均辐射之间的正相关也得到了强有力的支持。此外，辐射比MAT更能预测皮肤的反射率。我们还发现皮肤反射率与身体大小呈正相关，尽管在考虑到系统发育后，这一关系并不显著。皮肤反射率与热生物学指标无关，尽管不能排除混杂的影响，如方法差异。综上所述，这项研究为TMH在大地理尺度上的特异地运行提供了新的支持，提示了蜥蜴之间皮肤反射率的适应性变化。
1. The thermal melanism hypothesis (TMH) predicts that dark (low skin reflectance) individuals are at an advantage in cool climates as they heat faster and reach higher equilibrium temperatures than lighter (higher reflectance) individuals. However, tests of the TMH have yielded mixed support, especially in ectothermic vertebrates.2. Most studies to date have been undertaken at small spatial scales or using a few, closely related populations or species. Here, we therefore examine the TMH at large scales in heliothermic lizard species, testing two of its major predictions and a corollary thereof, using standard and phylogenetically corrected analyses.3. First, we test the prediction that skin reflectance and climate variables such as mean annual temperature (MAT) and global solar radiation are positively related across species. Second, we determine whether a positive relationship exists between skin reflectance and body mass. Third, since physiology, behaviour and morphology should be co-adapted, we test the prediction that skin reflectance and traits of thermal biology are positively related.4. We find strong support for a positive relationship between skin reflectance and mean annual radiation even after adjusting for phylogeny. Moreover, radiation was a better predictor of skin reflectance than MAT. We also find support for a positive relationship of skin reflectance with body size, although this was non-significant after accounting for phylogeny.5. Skin reflectance was not related to measures of thermal biology, although confounding effects such as methodological differences could not be ruled out.6. In summary, this study provides novel support for the TMH operating interspecifically at large geographic scales, suggesting adaptive variation of skin reflectance among lizards.