Date of this Version
Evolutionary Ecology Research, 2000, 2: 107–118
Many empirical studies suggest that females often prefer to mate with older males. It is generally assumed that females prefer older males because older males are of higher genetic quality. We used a viability-based simulation model to determine whether female preference for older mates is more likely to evolve than female preference for younger mates when males provide only sperm to females. The results of our simulations suggest that female preference for young and intermediate age mates is more likely to evolve than a strong preference for older mates, and that female preference based on male age will not evolve if there is a cost associated with the preference. Therefore, based on the results of our model, female preferences for older mates cannot be explained by ‘good genes’ models of sexual selection. A comparison of our results with those of a previously published model suggest that whether female preference for older males can be explained by ‘good genes’ models of sexual selection depends on age-specific survival probabilities. When juvenile survival is high and adult survival is low, older males have higher mean viability than younger males. As a result, female preference for older males will evolve. In contrast, when juvenile survival is low and adult survival is high, mean viability does not differ among males of different ages. Therefore, female preference for older males is unlikely to evolve. The importance of age-specific survival rates in determining the importance of a ‘good genes’ process suggests that future studies of sexual selection should consider potential effects of life-history variation.