Data from: Assessing the contributions of reduced immigrant viability and fecundity to reproductive isolation

Reduced fitness of immigrants from alternative environments is thought to be an important reproductive isolating barrier. Most studies evaluating the importance of the relative fitness of immigrants to speciation have focused on reduced survival of immigrants (i.e., immigrant inviability). However, variation in fecundity appears to have a greater impact on variation in fitness than does variation in viability, suggesting that reduced fecundity of immigrants could act as an important yet largely overlooked reproductive isolating barrier. Using a model and a survey of studies of local adaptation, we evaluate the relative strength of reduced immigrant viability and fecundity as potential causes of reproductive isolation. We found that reduced fecundity as compared to reduced viability as a reproductive isolating barrier should increase in importance as the relative costs of reproduction increase. Consistent with the elevated demands of reproduction reported in the literature, we found that reproductive isolation from reduced immigrant fecundity was of similar magnitude or greater than that from reduced immigrant viability, particularly in the early stages of speciation. These results suggest that the important role of differential fecundity in local adaptation extends to speciation.来自异质环境的外来者适合度降低，被认为是一类重要的生殖隔离障碍。大多数评估外来者相对适合度对物种形成重要性的研究，均聚焦于外来者存活能力下降，即外来者存活缺陷（immigrant inviability）。然而，繁殖力（fecundity）的变异对适合度变异的影响，较存活能力变异更为显著，这表明外来者繁殖力下降可作为一类重要却长期被忽视的生殖隔离障碍。我们通过构建模型与综述本地适应相关研究，评估了外来者存活能力下降与繁殖力下降作为生殖隔离潜在成因的相对强度。研究发现，随着繁殖相对成本的提升，相较于存活能力下降，以繁殖力下降构成的生殖隔离障碍的重要性会随之升高。与文献中报道的繁殖需求升高的结论一致，我们发现由外来者繁殖力下降引发的生殖隔离，其强度与外来者存活能力下降导致的生殖隔离相当甚至更高，在物种形成早期阶段尤为显著。上述结果表明，繁殖力差异在本地适应中的重要作用，可延伸至物种形成过程中。