Times needed to evolve mating cues under allopatry and parapatry.

The time needed for the evolution of mating cues that distinguish species, such as species-specific songs or plumage coloration in birds, has received little attention. Aiming to gain some understanding of the timing of the evolutionary process we here present models of how mating cues evolve in populations split into subpopulations between which there may (parapatry) or may not (allopatry) be migration. Mating cues can be either neutral or directly selected.

Allele frequencies and selection coefficients in locally adapted populations.

Understanding the role of natural selection in driving evolutionary change requires accurate estimates of the strength of selection acting at the genetic level in the wild. This is challenging to achieve but may be easier in the case of populations in migration-selection balance. When two populations are at equilibrium under migration-selection balance, there exist loci whose alleles are selected different ways in the two populations.

Sexual imprinting leads to speciation in locally adapted populations.

Sexual imprinting is widespread in birds and other species but its existence requires explanation. Our results suggest that sexual imprinting leads to speciation in locally-adapted populations if a neutral mating cue-e.g.

How phenotypic matching based on neutral mating cues enables speciation in locally adapted populations.

Maynard Smith's ( 1966, 100, 637) suggestion that in some cases a prerequisite for speciation is the existence of local ecological adaptations has not received much attention to date. Here, we test the hypothesis using a model like that of Maynard Smith but differing in the way animals disperse between niches. In previous studies, males disperse randomly between niches but females stay put in their natal niche.