Abstract：
Climate change is altering species ranges and reproductive interactions in existing ranges, offering species new scope to mate and hybridize. The outcomes will depend on how environmental factors shape reproductive barriers across life stages, yet this is rarely assessed across the environments that species encounter in nature. We assess prezygotic and postzygotic barriers, and their dependence on temperature and parental sex, in species of a reef-building tubeworm (Galeolaria) from a fast-warming biodiversity hotspot in southern Australia. By replicating pure and reciprocal hybrid crosses across 5 temperatures spanning species\' thermal ranges, we estimate thermal tolerance curves (defining niches) for crosses and reproductive isolation at each temperature. By also replicating crosses at 3 life stages, we partition the contributions of prezygotic barriers at fertilization, postzygotic barriers at embryogenesis, and postzygotic barriers at larval development to reproductive isolation. We show that barriers are weaker at fertilization and embryogenesis, but stronger and more temperature sensitive at larval development, as species diverge in thermal niche. Asymmetry of barriers between parental sexes, moreover, suggests a complex interplay between niche differentiation and maternal inheritance. Our findings point to a key role for temperature in reproductive isolation, but also challenges for predicting the fate of isolation in future climates.
摘要：
气候变化正在改变物种范围和现有范围内的生殖相互作用，提供物种交配和杂交的新范围。结果将取决于环境因素如何在生命阶段塑造生殖障碍，然而，这很少在物种在自然界中遇到的环境中进行评估。我们评估合子前和合子后屏障，以及他们对温度和父母性别的依赖，来自澳大利亚南部快速变暖的生物多样性热点地区的造礁管虫（Galeolaria）。通过复制跨越物种热范围的五个温度的纯杂交和互惠杂交，我们估计了每个温度下杂交和生殖隔离的耐热曲线（定义生态位）。通过在三个生命阶段复制杂交，我们划分了受精前合子屏障的贡献，胚胎发生的合子后障碍，和幼虫发育到生殖隔离的合子后障碍。我们表明受精和胚胎发生时的障碍较弱，但在幼虫发育时更强更敏感，随着物种在热生态位的分化。父母性别之间的障碍不对称，此外,表明生态位分化和母性遗传之间存在复杂的相互作用。我们的发现指出了温度在生殖隔离中的关键作用，但也是预测未来气候中孤立命运的挑战。
