Data from: Genome-wide SNPs reveal fine-scale differentiation among wingless alpine stonefly populations, and introgression between winged and wingless forms

Insect flight-loss is a repeated phenomenon in alpine habitats, where wing reduction is thought to enhance local recruitment and increase fecundity. One predicted consequence of flight loss is reduced dispersal ability, which should lead to population genetic differentiation and perhaps ultimately to speciation. Using a dataset of 15,123 SNP loci, we present comparative analyses of fine-scale population structure in co-distributed Zelandoperla stonefly species, across three parallel altitudinal transects in New Zealand's Rock and Pillar mountain range. We find that winged populations (altitude 200–500m; Z. decorata) show no genetic structuring within or among streams, suggesting substantial dispersal mediated by flight. By contrast, wingless populations (Z. fenestrata; altitude 200–1100m) exhibit distinct genetic clusters associated with each stream, and additional evidence of isolation by distance within streams. Our data support the hypothesis that wing-loss can initiate diversification in alpine insect populations over small spatial scales. The often deep phylogenetic placement of lowland Z. fenestrata within their stream-specific clades suggests the possibility of independent alpine colonization events for each stream. Additionally, the detection of winged, interspecific hybrid individuals raises the intriguing possibility that a previously flightless lineage could reacquire flight via introgression.

昆虫飞行能力丧失是高山生境中反复出现的现象，学界普遍认为翅退化可提升本地种群补充率并增强繁殖力。飞行能力丧失的一项可预测后果是扩散能力下降，这将导致种群遗传分化，甚至最终引发物种形成。本研究依托15123个单核苷酸多态性（Single Nucleotide Polymorphism, SNP）位点数据集，对新西兰罗克皮尔山脉（Rock and Pillar Mountain Range）内三条平行海拔样带中的同域分布泽兰襀属（Zelandoperla）石蝇物种的精细尺度种群结构开展比较分析。结果显示，具翅种群（分布海拔200–500m；装饰泽兰襀 Z. decorata）在溪流内部及溪流间均未呈现遗传结构，表明其通过飞行实现了广泛的扩散。与之形成鲜明对比的是，无翅种群（窗泽兰襀 Z. fenestrata；分布海拔200–1100m）则表现出与各溪流对应的独特遗传聚类，且在溪流内部存在距离隔离的额外证据。本研究数据支持以下假说：在较小空间尺度下，翅退化可启动高山昆虫种群的分化过程。低海拔窗泽兰襀（Z. fenestrata）在其溪流专属演化支中通常处于较深的系统发育位置，这提示各溪流可能存在独立的高山定殖事件。此外，本次研究检测到具翅的种间杂交个体，这引出了一个引人关注的可能性：此前丧失飞行能力的支系可通过渐渗杂交重新获得飞行能力。