Background: Interspecific mating often results in the loss of female reproductive success and can lead to the extinction of a species. In such situations, females evolve a stronger mate preference to avoid heterospecific mating, which promotes pre-mating barriers between species. Questions: What is the magnitude of reproductive character displacement and how large is the damage done by reproductive interference? What is the effect of female mate preference on reproductive character displacement? Can the character displacement prevent extinction of the species? Key assumptions: There are two closely related species whose individuals can mate but whose hybrids are inviable. One, the resident, lives in an isolated area where it is common. Individuals of the other, the invader, regularly migrate to the isolated area. Resident females accept mates based on a male ornament or other secondary sexual trait. Both female preference and the male trait are determined by sex-limited autosomal loci. Methods: Build mathematical models for male and female fitnesses. Analyse the evolution of male and female traits. Deduce the amount of character displacement caused by resident females evolving to prefer males that do not resemble invaders. Deduce the evolutionary change of resident male traits. Determine the effect on character displacement of varying the fitness cost of interspecific mating to the females. Calculate numerically the course of the evolutionary transition as well as the time required to complete it. Study the chance that the invasion will cause the extinction of the resident species. Conclusions: Both the resident male trait and the resident female preference evolve away from the male trait of the invader. The evolutionary shift in the male trait is largest at an intermediate intensity of female mate choice. Equilibrium in male and female traits is maintained by the balance between natural and sexual selection, and the male trait value most preferred by females is more exaggerated than the actual male trait. Sexual dimorphism may evolve if female morphology (as opposed to female preference) remains at the viability optimum. The risk of extinction of the resident species strongly depends on the speed of extinction relative to the time it takes for the adaptation to evolve.
|Number of pages
|Evolutionary Ecology Research
|Published - 2013
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics