Am Nat. 2022 Sep;200(3):E93-E109. doi: 10.1086/720365. Epub 2022 Jul 20.
AbstractIt is thought that two species can coexist if they use different resources present in the environment, yet this assumes that species are completely reproductively isolated. We simulate coexistence outcomes for two sympatric species that are ecologically differentiated but have incomplete reproductive isolation. The consequences of interbreeding crucially depend on hybrid fitness. When hybrid fitness is high, just a small rate of hybridization can lead to collapse of two species into one. Low hybrid fitness can cause population declines, making extinction of one or both species likely. High intrinsic growth rates result in higher reproductive rates when populations are below carrying capacity, reducing the probability of extinction and increasing the probability of stable coexistence at moderate levels of assortative mating and hybrid fitness. Very strong but incomplete assortative mating can induce low hybrid fitness via a mating disadvantage to rare genotypes, and this can stabilize coexistence of two species at high but incomplete levels of assortative mating. Given these results and evidence that it may take many millions of years of divergence before related species become sympatric, we postulate that coexistence of closely related species is more often limited by insufficient assortative mating than by insufficient ecological differentiation.
摘要人们认为，如果两个物种能够利用环境中存在的不同资源，它们就可以共存，但这假设物种是完全生殖隔离的。我们模拟了两个具有生态差异但不完全生殖隔离的同域物种的共存结果。杂交的后果在很大程度上取决于杂种的适应性。当杂种适应性高时，即使很小的杂交率也可能导致两个物种融合为一个。杂种适应性低会导致种群数量下降，使一个或两个物种灭绝的可能性增加。当种群数量低于承载能力时，高的固有增长率会导致生殖率增加，从而降低灭绝的概率，并增加在中等程度的交配选择和杂种适应性下稳定共存的概率。非常强但不完全的交配选择可以通过对稀有基因型的交配劣势来降低杂种适应性，这可以在高但不完全的交配选择水平上稳定两个物种的共存。考虑到这些结果以及相关证据表明，相关物种需要数百万年的分化才能成为同域物种，我们假设，近亲物种的共存更多地受到交配选择不足的限制，而不是生态分化不足的限制。
