Disassortative mating for boldness decreases reproductive success in the guppy

Consistent individual differences in personality or temperament have been observed in many animal taxa, and one particular trait, boldness, has been studied extensively. Most studies on mate choice and personality have focused on female preference and have showed that females prefer to mate with bolder males. However, the influence of the female’s personality on this mate preference and on her compatibility with a mate with particular traits has been largely neglected. Here, using the guppy Poecilia reticulata, we investigated the effect of female boldness on mate choice and of the combinations of this trait in the male and female of a mating pair on parturition and brood size. Our results showed that female boldness did not affect mate choice, and brood size was independent of the boldness of the male and female in a pair. However, overall, females who mated with males with a dissimilar degree of boldness to themselves had a lower parturition success than females who mated with males with a similar degree of boldness. This work suggests that the combination of boldness characteristics within a pair influences reproductive success and that individuals of similar personality are more compatible in reproduction. The lower success of disassortative matings is consistent with the hypothesis that variation in personalities is maintained by disruptive or frequency-dependent selection, driven by contrasting physical or social environments that favor alternative rather than intermediate behavioral phenotypes.