Evolution of premating barriers in interspecific contacts: a quantitative genetic modeling

Ryo Yamaguchi and Yoh Iwasa
(Kyushu University)

12/9/19, 13:30 - 15:00 at Room 3631 (6th floor of building 3 of the Faculty of Sciences)

Interspecific mating often causes the loss of female reproductive success, and sometimes results in the extinction of a species. In such a case, females are believed to evolve stronger mate preference to avoid heterospecific mating, which promotes premating barriers between species. Here we analyze this evolutionary process based on a quantitative genetic model for the female mate preference and male secondary sexual traits that facilitate species recognition when hybrids are not viable. The magnitude of the evolutionary shift in the male traits is the largest when the intensity of the female mate choice is mildly large. At the ESS, the male trait most preferred by females is more exaggerated than the male trait. Sexual dimorphism evolves as female trait remains the viability optimum. If two species were not made in contact before, their males quickly evolve reproductive character displacement when they become sympatry by invasion, migration, or spatial spread. When an alien species invades and causes reproductive interference, the resident species can mitigate the risk of extinction by the quick evolution of reproductive character displacement.
Key words: reproductive character displacement, prezygotic isolation, heterospecific mating, quantitative trait, sexual selection, extinction.

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