Data from: Effects of environmental disturbance on phenotypic variation: an integrated assessment of canalization, developmental stability, modularity and allometry in lizard head shape

When populations experience suboptimal conditions, the mechanisms involved in the regulation of phenotypic variation can be challenged, resulting in increased phenotypic variance. This kind of disturbance can be diagnosed by using morphometric tools to study morphological patterns at different hierarchical levels and evaluate canalization, developmental stability, integration, modularity and allometry. We assess the effect of urbanization on phenotypic variation in the common wall lizard, Podarcis muralis, using geometric morphometrics to assess disturbance to head shape development. The head shapes of urban lizards were more variable and less symmetric, suggesting that urban living is more likely to disturb development. Head shape variation was congruent within and across individuals, which indicated that canalization and developmental stability are two related phenomena in these organisms. Further, urban lizards exhibited smaller mean head sizes, divergent size-shape allometries, and increased deviation from within-group allometric lines. This suggests that mechanisms regulating head shape allometry may also be disrupted. The integrated evaluation of several measures of developmental instability at different hierarchical levels, which provided in this case congruent results, can be a powerful methodological guide for future studies, as it enhances the detection of environmental disturbances on phenotypic variation and it aids biological interpretation of the results.

当种群处于次优环境条件时，调控表型变异的相关机制可能受到干扰，进而导致表型方差升高。此类发育扰动可通过形态测量工具进行诊断：通过分析不同层级的形态模式，并评估渠道化（canalization）、发育稳定性（developmental stability）、形态整合（integration）、模块性（modularity）与异速生长（allometry）等核心指标。本研究以普通壁蜥（Podarcis muralis）为研究对象，利用几何形态测量学（geometric morphometrics）探究城市化对其表型变异的影响，并评估头部形状发育所受的扰动情况。结果显示，城市化生境中的壁蜥头部形状变异程度更高、对称性更差，表明城市生活更易干扰其发育过程。个体内部及个体间的头部形状变异均呈现一致性，这说明在该物种中，渠道化与发育稳定性是两种相关的发育现象。此外，城市化生境中的壁蜥平均头部尺寸更小，其体型-形状异速生长模式存在分化，且与种群内异速生长线的偏离程度更高。这提示调控头部形状异速生长的相关机制同样可能受到干扰。本研究针对不同层级的多项发育不稳定性评估指标开展整合分析，最终得到了一致的结果。此类整合评估可作为未来相关研究的高效方法学指南，因其能够提升对环境扰动引发表型变异的检测能力，并有助于研究结果的生物学阐释。