Data from: Regional divergence and mosaic spatial distribution of two closely related damselfly species (Enallagma hageni and Enallagma ebrium)

North American Enallagma damselflies radiated during the Pleistocene, and species differ mainly by reproductive structures. Although morphologically very different, Enallagma hageni and Enallagma ebrium are genetically very similar. Partitioning of genetic variation (AFLP), isolation by distance and clustering analyses indicate that these morphospecies are locally differentiated genetically. Spatial analyses show that they are rarely sympatric at local sites, and their distributions form a mosaic of patches where one is clearly dominant over hundreds of square kilometers. However, these morphospecies are also not genetically more similar when they are sympatric, indicating that hybridization is probably not occurring. Given that these morphospecies are ecologically equivalent, strong assortative mating, reproductive interference and fast post-glacial recolonization may explain the origin and maintenance of these distributional patches across eastern North America. By limiting opportunities for gene flow, reproductive interference may play an unsuspected role in accelerating genetic differentiation in the early phases of nonecological speciation.更新世时期，北美异痣蟌属（Enallagma）豆娘发生了辐射演化，物种间的差异主要体现于生殖结构。尽管哈氏异痣蟌（Enallagma hageni）与埃氏异痣蟌（Enallagma ebrium）在形态上差异显著，但二者的遗传相似度却极高。基于扩增片段长度多态性（AFLP）的遗传变异分区分析、距离隔离效应分析以及聚类分析均表明，这些形态种在局部尺度上存在遗传分化。空间分析显示，二者极少在局部样地同域共存，其分布呈现斑块镶嵌格局——在数百平方公里的范围内，其中一个物种占据绝对优势。然而，当二者同域分布时，它们的遗传相似度并未显著提升，这表明杂交事件大概率并未发生。鉴于这些形态种的生态位等效，强烈的选型交配、生殖干扰以及快速的冰期后再定植过程，或可解释北美东部地区这类分布斑块的起源与维持机制。通过限制基因交流的机会，生殖干扰或许在非生态物种形成的早期阶段，对加速遗传分化起到了此前未被重视的作用。