Recently diversified taxa commonly do not show complete reproductive isolation, and thus they represent an interesting model for studying the occurrence of hybridization and its influence on the integrity of species. In this study, we aim to elucidate the occurrence of hybridization and discuss species boundaries between three Aechmea spp. (Bromeliaceae) from southern Brazil. To achieve these aims, we used ten nuclear and six plastid microsatellite loci. We also investigated morphological and ecological differentiation and reproductive compatibility through interspecific cross-pollination experiments with these species. Molecular analyses confirmed the occurrence of hybridization between the three species, but interspecific gene flow was higher between A. comata and A. kertesziae than between A. comata and A. caudata. These Aechmea spp. showed morphological differentiation, and the results of the artificial interspecific crosses indicated that they can intercross. Aechmea caudata and A. kertesziae show distinct microhabitat preferences, whereas A. comata thrives in a microhabitat that is also inhabited by the other species. Despite the potential reproductive barriers being weak, especially those between A. comata and A. kertesziae, they may maintain the boundaries between these species and their integrity in sympatric populations.

中文翻译：

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来自巴西大西洋森林的三种同域凤梨科植物的杂交和物种界限

最近多样化的分类群通常不表现出完全的生殖隔离，因此它们代表了一个有趣的模型来研究杂交的发生及其对物种完整性的影响。在这项研究中，我们旨在阐明杂交的发生并讨论三种 Aechmea spp 之间的物种边界。（菠萝科）来自巴西南部。为了实现这些目标，我们使用了十个核和六个质体微卫星基因座。我们还通过这些物种的种间异花授粉实验研究了形态和生态分化以及生殖相容性。分子分析证实了这三个物种之间发生了杂交，但 A. comata 和 A. kertesziae 之间的种间基因流高于 A. comata 和 A. caudata 之间的基因流。这些 Aechmea spp。表现出形态分化，人工种间杂交的结果表明它们可以杂交。Aechmea caudata 和 A. kertesziae 表现出不同的微生境偏好，而 A. comata 在其他物种也居住的微生境中茁壮成长。尽管潜在的生殖障碍很弱，尤其是 A. comata 和 A. kertesziae 之间的生殖障碍，但它们可能会保持这些物种之间的界限及其在同域种群中的完整性。