Algal-searching ability in laboratory experiments reflects orange spot coloration of the male guppy in the wild

In the guppy Poecilia reticulata, females often choose their mates on the basis of the orange spot coloration of males. It is known that the colour saturation of orange spots in males is determined by the amount of intake of algae, a natural source of carotenoids. In this study, we examined the relationship between sexually selected traits in wild-caught males and their algal-searching ability in a laboratory experiment. Neither the body size nor the orange spot size of males correlated significantly with the algal-searching ability. However, males that possessed orange spots with a high colour saturation in the wild exhibited a high searching ability in the laboratory. This result suggests that the algal-searching score of males in the laboratory experiment indicated their algal-foraging ability in the natural environment. In a previous study, the algal-searching ability of guppies in a laboratory experiment was demonstrated to be a heritable trait. The result of this study further supported the hypothesis that female mate preferences for carotenoid-based coloration of males have evolved via indirect benefits such as the high foraging ability of their offspring.