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加繁殖力。飞行能力丧失的一个预测性后果是扩散能力下降，这会引发种群遗传分化，甚至最终导致物种形成。本研究基于包含15123个单核苷酸多态性位点（SNP loci）的数据集，对新西兰洛克与皮勒山脉（Rock and Pillar mountain range）内三条平行海拔样带中同域分布的新西兰石蝇属（Zelandoperla）石蝇物种开展精细尺度种群结构的比较分析。研究发现，具翅种群（海拔200~500米；装饰新西兰石蝇Z. decorata）在溪流内部及溪流间均未表现出遗传结构，表明其飞行介导了广泛的扩散。相比之下，无翅种群（窗翅新西兰石蝇Z. fenestrata；海拔200~1100米）则呈现出与每条溪流对应的独特遗传聚类，同时存在溪流内部距离隔离的额外证据。本研究数据支持以下假说：在小空间尺度下，翅退化可启动高山昆虫种群的分化过程。低海拔窗翅新西兰石蝇通常在其溪流特异性演化支中处于较深的系统发育位置，这表明每条溪流可能存在独立的高山定殖事件。此外，研究还检测到具翅的种间杂交个体，这引出了一个有趣的可能性：此前丧失飞行能力的支系可通过基因渐渗重新获得飞行能力。