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) by 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. Furthermore, 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 aids biological interpretation of the results.

当种群处于亚适条件（suboptimal conditions）下时，参与表型变异（phenotypic variation）调控的机制可能会受到干扰，进而导致表型方差（phenotypic variance）升高。此类扰动可通过形态测量学工具（morphometric tools）开展不同层级的形态模式研究，并对发育缓冲（canalization）、发育稳定性（developmental stability）、形态整合（integration）、模块化（modularity）以及异速生长（allometry）进行评估，从而实现诊断识别。本研究以普通壁蜥（Podarcis muralis）为研究对象，借助几何形态测量学（geometric morphometrics）分析头部形态发育所受的扰动，以此评估城市化对其表型变异的影响。结果显示，城市生境中的壁蜥头部形态变异程度更高、对称程度更低，表明城市生活更易对其发育过程造成扰动。个体内部及个体间的头部形态变异具有一致性，这表明在这类生物中，发育缓冲与发育稳定性是两种相关的发育现象。此外，城市种群的壁蜥平均头部尺寸更小，体型-形态异速生长关系与对照组存在显著差异，且其偏离种群内异速生长线的程度更高。这表明调控头部形态异速生长的机制同样可能受到了扰动。本研究对不同层级的多种发育不稳定性（developmental instability）指标进行了整合评估且得到了一致的结果，该方法可作为未来相关研究的有力方法论指导，因为它能够提升对环境扰动引发表型变异的检测能力，并有助于对研究结果进行生物学阐释。