A FURTHER PERSPECTIVE ON SPECIATION BY REINFORCEMENT

摘要

HUGH PATERSON was one of the foremost critics of the idea that species arise via disruptive selection on their mating behaviours, the so-called model of «speci-ation by reinforcement». Under this hypothesis, we start with two populations that have diverged in allopatry, perhaps as a result of local adaptation. The critical assumption is that, because of this divergence, crosses between individuals from these separate populations result in offspring with reduced fertility or viability. In the next step of the process, these two populations become sympatric and hybridization can occur. Clearly, any individuals with a tendency to mate with individuals from their own population have a selective advantage over those that do not because they produce fewer of the disadvantaged hybrids. Selection thus leads to the divergence of mating behaviours of the two populations and hence the production of fewer hybrids, continuing until hybridization ceases and we are left with two species.