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.来自异源环境的迁入者适合度降低，被视为一类关键的生殖隔离屏障（reproductive isolating barrier）。绝大多数评估迁入者相对适合度对物种形成重要性的研究，均聚焦于迁入者的生存力下降（即迁入者存活劣势，immigrant inviability）。然而，繁殖力（fecundity）的变异对适合度变异的贡献，似乎较生存力变异更为显著，这提示迁入者繁殖力下降或可作为一类重要却长期被忽视的生殖隔离障碍。本研究通过构建理论模型并开展本地适应（local adaptation）领域现有研究的综述分析，评估了迁入者生存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升高，以繁殖力下降作为生殖隔离屏障的重要性将逐步提升。与文献中报道的繁殖需求升高现象相一致，本研究结果显示：由迁入者繁殖力下降引发的生殖隔离，其强度与迁入者生存力下降引发的隔离程度相当甚至更高，在物种形成的早期阶段尤为突出。上述结果表明，繁殖力差异在本地适应中发挥的重要作用，同样可延伸至物种形成过程。