Pfennig Karin S
Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA.
Curr Zool. 2016 Apr;62(2):145-154. doi: 10.1093/cz/zow033. Epub 2016 Mar 24.
When hybridization results in reduced fitness, natural selection is expected to favor the evolution of traits that minimize the likelihood of hybridizing in the first place. This process, termed reinforcement (or, more generally, reproductive character displacement), thereby contributes to the evolution of enhanced reproductive isolation between hybridizing groups. By enhancing reproductive isolation in this way, reinforcement plays an important role in the final stages of speciation. However, reinforcement can also contribute to the early stages of speciation. Specifically, because selection to avoid hybridization occurs only in sympatric populations, the unfolding of reinforcement can lead to the evolution of traits in sympatric populations that reduce reproduction between conspecifics in sympatry versus those in allopatry. Thus, reinforcement between species can lead to reproductive isolation-and possibly speciation-between populations in sympatry versus those in allopatry or among different sympatric populations. Here, I describe how this process can occur, the conditions under which it is most likely to occur, and the empirical data needed to evaluate the hypothesis that reinforcement can initiate speciation.
当杂交导致适合度降低时，自然选择有望促进那些首先将杂交可能性降至最低的性状的进化。这一过程被称为强化（或者更普遍地称为生殖性状替换），从而有助于杂交群体之间增强生殖隔离的进化。通过以这种方式增强生殖隔离，强化在物种形成的最后阶段发挥着重要作用。然而，强化也可能对物种形成的早期阶段有贡献。具体而言，由于避免杂交的选择仅发生在同域种群中，强化的展开可能导致同域种群中出现一些性状的进化，这些性状会减少同域中的同种个体与异域中的同种个体之间的繁殖。因此，物种之间的强化可能导致同域种群与异域种群之间或不同同域种群之间产生生殖隔离，甚至可能导致物种形成。在此，我描述了这个过程是如何发生的、最有可能发生的条件，以及评估强化能够引发物种形成这一假说所需的实证数据。
