Research Facility Studenec, Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic.
Faculty of Veterinary Hygiene and Ecology, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic.
PLoS One. 2020 Dec 7;15(12):e0231804. doi: 10.1371/journal.pone.0231804. eCollection 2020.
The role of adaptive divergence in the formation of new species has been the subject of much recent debate. The most direct evidence comes from traits that can be shown to have diverged under natural selection and that now contribute to reproductive isolation. Here, we investigate differential adaptation of two fire-bellied toads (Anura, Bombinatoridae) to two types of aquatic habitat. Bombina bombina and B. variegata are two anciently diverged taxa that now reproduce in predator-rich ponds and ephemeral aquatic sites, respectively. Nevertheless, they hybridise extensively wherever their distribution ranges adjoin. We show in laboratory experiments that, as expected, B. variegata tadpoles are at relatively greater risk of predation from dragonfly larvae, even when they display a predator-induced phenotype. These tadpoles spent relatively more time swimming and so prompted more attacks from the visually hunting predators. We argue in the discussion that genomic regions linked to high activity in B. variegata should be barred from introgression into the B. bombina gene pool and thus contribute to gene flow barriers that keep the two taxa from merging into one.
适应性分歧在新物种形成中的作用一直是最近争论的主题。最直接的证据来自那些可以被证明在自然选择下发生分歧的特征，而这些特征现在有助于生殖隔离。在这里，我们研究了两种鼓起肚子的蟾蜍（两栖类，蟾蜍科）对两种水生栖息地的差异适应。Bombina bombina 和 B. variegata 是两个古老分化的类群，现在分别在有捕食者的池塘和短暂的水生场所繁殖。然而，只要它们的分布范围相邻，它们就会广泛杂交。我们在实验室实验中表明，正如预期的那样，B. variegata 蝌蚪从蜻蜓幼虫那里受到捕食的风险相对更大，即使它们表现出一种受捕食者诱导的表型。这些蝌蚪花更多的时间游泳，因此更容易受到视觉捕猎的捕食者的攻击。我们在讨论中认为，与 B. variegata 高活性相关的基因组区域应被阻止向 B. bombina 基因库的基因渗入，从而有助于阻止两个类群融合成一个的基因流动障碍。
