Reproductive interference can promote recurrent speciation

Many consequences of reproductive interference have important implications in biodiversity conservation policy. After briefly summarizing our comments on the articles in this special feature, we focus on the role of reproductive interference in speciation due to geographic isolation with only infrequent migration between islands (or island-like habitats). As two isolated populations accumulate incompatible genes, they became genetically distinct. When a rare migration occurs from one island to the other, reproductive interference greatly affects its outcome. A paper in this special feature showed that either the migrant or resident population becomes extinct, presumably due to reproductive interference. However, we also found cases in which the migrant and resident populations evolved quickly to avoid mixing, either by character displacement or spatial segregation within the island. To improve our understanding of the dynamics of species diversity, theoretical modeling and empirical studies of reproductive interference immediately after invasion are important targets for future studies.