Interactions among quantitative traits in the course of sympatric speciation

Publisher Website
Google Scholar
Abstract
Sympatric speciation, the origin of two or more species from a single local population, has almost certainly been involved in formation of several species flocks1,2,3,4, and may be fairly common in nature5. The most straightforward scenario for sympatric speciation requires disruptive selection favouring two substantially different phenotypes, and consists of the evolution of reproductive isolation between them followed by the elimination of all intermediate phenotypes6. Here we use the hypergeometric phenotypic model7,8,9,10 to show that sympatric speciation is possible even when fitness and mate choice depend on different quantitative traits, so that speciation must involve formation of covariance between these traits. The increase in the number of variable lociaffecting fitness facilitates sympatric speciation, whereas the increase in the number of variable loci affecting mate choice has the opposite effect. These predictions may enable more cases of sympatric speciation to be identified.