Local adaptation can occur at small spatial scales relative to the dispersal capacity of species. Alpine ecosystems have sharp environmental clines that offer an opportunity to investigate the effects of fine‐scale shifts in species’ niche breadth on adaptive genetic processes. Here we examine two grasshopper species endemic to the Australian Alps (Kosciuscola spp.) that differ in elevational niche breadth: one broader, K. usitatus (1400–2200 m), and one narrower, K. tristis (1600–2000 m). We examine signatures of selection with respect to environmental and morphological variables in two mountain regions using F_ST outlier tests and environmental association analyses (EAAs) applied to single nucleotide polymorphism (SNP) data (K. usitatus: 9017 SNPs, n = 130; K. tristis: 7363 SNPs, n = 135). Stronger genetic structure was found in the more narrowly distributed K. tristis, which showed almost twice the number of SNPs under putative selection (10.8%) compared with K. usitatus (5.3%). When examining SNPs in common across species (n = 3058), 260 SNPs (8.5%) were outliers shared across species, and these were mostly associated with elevation, a proxy for temperature, suggesting parallel adaptive processes in response to climatic drivers. Additive polygenic scores (an estimate of the cumulative signal of selection across all candidate loci) were nonlinearly and positively correlated with elevation in both species. However, a steeper correlation in K. tristis indicated a stronger signal of spatially varying selection towards higher elevations. Our study illustrates that the niche breadth of co‐occurring and related species distributed along the same environmental cline is associated with differences in patterns of microgeographical adaptation.

中文翻译：

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微观地理适应性对应于同类山地蝗虫的海拔分布

相对于物种的扩散能力，局部适应可能发生在较小的空间尺度上。高山生态系统具有鲜明的环境变化，为研究物种生态位宽度的精细变化对适应性遗传过程的影响提供了机会。在这里，我们考察2只蝗虫特有的澳大利亚山脉（Kosciuscola spp。）的，在正视生态位宽度不同：一个更广泛的，K. usitatus（一四○○年至2200年米），和一个窄，K. tristis（1600-2000米）。我们使用F _ST在两个山区检查关于环境和形态变量的选择特征离群值测试和环境关联分析（必需氨基酸）施加到单核苷酸多态性（SNP）的数据（K. usitatus：9017个SNP，Ñ  = 130; K. tristis：7363个SNP，Ñ  = 135）。在分布更狭窄的三面体K. tristis中发现了更强的遗传结构，与拟南芥（K. usitatus）（5.3％）相比，该结构显示出推定选择的SNP数量几乎是其两倍（10.8 ％）。在检查跨物种共有的SNP时（n = 3058），有260个SNP（8.5％）是跨物种共享的异常值，并且这些异常大多与海拔（温度的代表）相关，表明对气候驱动因素有平行的适应过程。加性多基因评分（所有候选基因座上选择的累积选择信号的估计值）与两个物种的海拔呈非线性正相关。但是，三面体K. tristis中较陡的相关性表明，朝向更高海拔的空间变化选择的信号更强。我们的研究表明，沿同一环境线分布的共生和相关物种的利基宽度与微观地理适应模式的差异有关。