Invasive species present an opportunity to test the association between selective forces and adaptive morphological traits because these species can experience rapid changes when introduced to new environments. One such invader is the common myna (Acridotheres tristis), a broadly ranging avian species that has been introduced on most continents and many oceanic islands. Here, we studied morphological variability in native and introduced populations of common mynas to identify the key environmental variables correlated with local phenotypic variation during biological invasions. In particular, we aimed to determine whether similar selective pressures acted on populations in the native range and the introduced ranges, and whether the same factors shaped morphological variation in different introduced populations. We recorded eight morphological measurements from 1,331 individuals across sites throughout most of the common myna’s range, as well as climatic, topographic and anthropogenic environmental data, sex and age of individuals, and years since local introduction. We found inconsistent signals of morphological adaptation in the native population, representing different patterns between females and males. Conversely, urbanization was a significant explanatory factor of phenotypic shifts in introduced populations, especially with regards to foraging-related traits. Moreover, we found that adaptation occurred differently across two focal introduced populations (Sydney, Australia and Israel). Therefore, caution is required in studies relating to evolutionary adaptations and predictions made regarding characteristics of invasive populations within a limited range of their introduced ranges. Our results also indicate a major role for urbanization in impacting the shape and size of foraging-related features in this broadly-distributed invasive species, emphasizing the impact of human-induced environmental changes upon the trajectories of biological invasions and, ultimately, their effects on native biodiversity.

入侵物种为检验选择性力与适应性形态特征之间的联系提供了机会，因为这些物种在引入新环境后会经历快速变化。普通八哥（Acridotheres tristis）就是这样一种侵略者。），是一种广泛分布的鸟类，已在大多数大陆和许多大洋岛屿上引入。在这里，我们研究了本地和引进的常见八哥种群的形态变异性，以识别与生物入侵过程中局部表型变异相关的关键环境变量。特别是，我们旨在确定相似的选择压力是否作用于天然范围和引入范围内的种群，以及相同的因素是否影响了不同引入种群的形态变异。我们记录了在整个常见八哥范围内各个地点的1,331个个体的八种形态学测量值，以及气候，地形和人为环境数据，个体的性别和年龄以及自当地引入以来的年限。我们在本地人口中发现不一致的形态适应信号，代表女性和男性之间的不同模式。相反，城市化是引入人口表型变化的重要解释因素，尤其是在觅食相关性状方面。此外，我们发现在两个重点引进人群（悉尼，澳大利亚和以色列）中，适应发生的方式有所不同。因此，在与进化适应有关的研究中，以及关于在其引入范围的有限范围内的侵入性种群的特征所作的预测时，需要谨慎行事。我们的研究结果还表明，城市化在影响这种分布广泛的入侵物种中与觅食相关的特征的形状和大小方面起着重要作用，