Mate sampling influences the intensity of sexual selection and the rate of male trait evolution (#427)
Mate sampling, the fact that females must choose their mates from a sample of the males in the population, influences many aspects of mate choice and mating systems. We used spatially explicit individual based simulations to investigate the effect of mate sampling on the intensity of sexual selection and its long term evolutionary effects. We observed that an increase in the number of males sampled by each female promotes an increase in the intensity of sexual selection, as measured by both Imates and selection gradient. We also ran evolutionary simulations in which females had unbounded preference for large male trait values, whereas males were under stabilizing natural selection for that same trait. As a result, an increase in the number of males sampled by each female promoted more exaggerated male traits after 50 generations. The consequences of mate sampling may explain why lekking species are those with the most exaggerated male ornaments, since male aggregations allow females to sample a large number of males. We argue that factors that influence the number of males sampled by each female (including spatial distribution of individuals, movement patterns, female perception range, and long-range male-female communication) are important modulators of the intensity and evolutionary result of sexual selection in natural populations.