Am Nat. 2021 Jun;197(6):732-739. doi: 10.1086/714139. Epub 2021 Apr 19.
AbstractThe role of divergent selection between alternative environments in promoting reproductive isolation (RI) between lineages is well recognized. However, most studies view each divergent environment as homogenous, thereby overlooking the potential role within-environment variation plays in RI between differentiating lineages. Here, we test the importance of microenvironmental variation in RI by using individual trees of two host plants, each harboring locally adapted populations of the cynipid wasp . We compared the fitness surrogate (survival) of offspring from hybrid crosses with resident crosses across individual trees on each of two primary host plants, and . We found evidence of weak hybrid inviability between host-associated lineages of despite strong genomic differentiation. However, averaging across environments masked great variation in hybrid fitness on individual trees, where hybrids performed worse than, equal to, or better than residents. Thus, considering the environmental context of hybridization is critical to improving the predictability of divergence under variable selection.
摘要
在促进谱系间生殖隔离（RI）方面，不同环境之间的发散选择的作用得到了广泛认可。然而，大多数研究将每个发散环境视为同质的，从而忽略了环境内变异在分化谱系之间 RI 中的潜在作用。在这里，我们通过使用两种宿主植物的个体树木来测试微环境变异在 RI 中的重要性，这两种植物都拥有本地适应的小蜂种群。我们比较了杂种与驻留杂种在两个主要宿主植物上的个体树木上的适合度替代物（存活率），和。尽管存在强烈的基因组分化，但我们发现尽管存在强烈的基因组分化，但在与宿主相关的谱系之间，存在较弱的杂种不育性的证据。然而，在跨环境平均化的情况下，个体树木上的杂种适合度存在很大的变化，杂种的表现不如、等于或优于居民。因此，考虑杂交的环境背景对于提高在可变选择下的分歧的可预测性至关重要。
