Diet color affects female preference for mate color in the guppy Poecilia reticulata

It has been argued that a preexisting sensory bias for food color influences female mate preference for male ornament color. However, the effect of diet color over a short period on female preference for color-polymorphic male ornaments has not yet been investigated. In this study, we examined the effect of diet color on female preference for mate color in the guppy Poecilia reticulata, with color-polymorphic ornaments such as orange and black spots. From an early age, females were reared on a diet with orange and black color, respectively. A dichotomous mate choice experiment using females was conducted between males with large orange spots and males with large black spots. Females fed on an orange-colored diet preferred males with large orange spots, whereas those fed on a black-colored diet preferred males with large black spots. Afterward, the diet color treatment for the females was reversed for seven days. This dietary color alteration resulted in the reversal of female preference for male color. These results suggest that diet color has a great influence on female preference for mate color, even within a short period, and environmental gradients may function to maintain color-polymorphic male ornaments in this species.