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.

当种群处于亚适宜条件时，调控表型变异的相关机制可能受到挑战，进而引发表型方差增大。此类干扰可通过形态测量工具进行检测分析：在不同层级水平上分析形态模式，并对发育渠化（canalization）、发育稳定性（developmental stability）、形态整合、模块化以及异速生长（allometry）进行评估。本研究以普通壁蜥（Podarcis muralis）为对象，利用几何形态测量学（geometric morphometrics）分析头部形态发育所受的干扰，以此评估城市化对其表型变异的影响。结果显示，城市种群壁蜥的头部形态变异度更高、对称性更弱，表明城市生境更易对发育过程造成干扰。个体内部与个体间的头部形态变异具有一致性，这说明该类生物的发育渠化与发育稳定性属于两种相关的发育现象。此外，城市种群壁蜥的平均头部尺寸更小，其体型-形状异速生长关系存在分化，且偏离组内异速生长线的程度更高，这提示调控头部形态异速生长的相关机制同样可能遭到破坏。本研究对不同层级的多项发育不稳定性指标进行了整合评估并获得了一致的结果，该方法可有效增强环境干扰对表型变异影响的检测能力，同时有助于对研究结果开展生物学解读，可为未来相关研究提供极具参考价值的方法学指南。