Data from: The role of environment and core-margin effects on range-wide phenotypic variation of a montane grasshopper

The integration of genetic information with ecological and phenotypic data constitutes an effective approach to gain insight into the mechanisms determining interpopulation variability and the evolutionary processes underlying local adaptation and incipient speciation. Here, we use the Pyrenean Morales grasshopper (Chorthippus saulcyi moralesi) as study system to (i) analyze the relative role of genetic drift and selection on range-wide patterns of phenotypic differentiation and (ii) identify the potential selective agents (environment, elevation) responsible for variation. We also test the hypothesis that (iii) the development of dispersal-related traits is associated with different parameters related to population persistence/turnover, including habitat suitability stability over the last 120 000 years, distance to the species distribution core, and population genetic variability. Our results indicate that selection shaped phenotypic differentiation across all the studied morphological traits (body size, forewing length and shape). Subsequent analyses revealed that among-population differentiation in forewing length was significantly explained by a temperature gradient, suggesting an adaptive response to thermoregulation or flight performance under contrasting temperature regimes. We found support for our hypothesis predicting a positive association between the distance to the species distribution core and the development of dispersal-related morphology, which suggests increased dispersal capability in populations located at range edges that, in turn, exhibit lower levels of genetic variability. Overall, our results indicate that range-wide patterns of phenotypic variation are partially explained by adaptation in response to local environmental conditions and differences in habitat persistence between core and peripheral populations.

将遗传信息与生态、表型数据相结合，是解析种群间变异决定机制以及局部适应与初期物种形成背后进化过程的有效途径。本研究以比利牛斯莫拉莱斯蚱蜢（Chorthippus saulcyi moralesi）为研究系统，开展三项工作：（i）分析遗传漂变与选择在全分布区表型分化格局中的相对作用；（ii）鉴定引发表型变异的潜在选择因子（环境、海拔）；（iii）验证“扩散相关性状的发育与种群存续/更替的多项参数存在关联”这一假说，这些参数包括过去12万年以来的生境适宜性稳定性、距物种分布核心区的距离，以及种群遗传变异水平。
研究结果显示，选择作用塑造了所有被测形态性状（体型大小、前翅长度与形状）的跨分布区表型分化格局。后续分析表明，前翅长度的种群间分化可由温度梯度显著解释，提示其为不同温度条件下针对体温调节或飞行性能的适应性响应。本研究支持了“距物种分布核心区的距离与扩散相关形态性状的发育呈正相关”的假说，这意味着分布区边缘种群具备更强的扩散能力，而此类种群的遗传变异水平通常更低。
总体而言，本研究结果表明，全分布区的表型变异格局可部分由针对局域环境条件的适应，以及核心种群与边缘种群间的生境存续差异所解释。