Do Darker Colors Influence Poecilia reticulata Sexual Selection?

Abstract

There are different factors that possibly contribute to sexual selection of male guppies, such as color and size. When a male guppy is trying to court a female, they display sexual selection behaviors such as chasing and biting, fanning their fins, or forming the body into a sigmoid display (French 2016). Studies have shown that female guppies are more attracted to male guppies of brighter colors (Kodric-Brown et. al 2001), and we wondered what colors affected the sexual selection of male guppies for female mates, and hypothesized that darker colors such as navy or ocean blue are more attractive to male guppies. We tested this hypothesis using 3D models and collected the average time that five guppies spent with an ocean blue experimental model and a gray control model, both the same size and in the tanks at the same time. We hypothesized that because of the wavelength of darker colors like dark blue and black, the male guppies would be more drawn to an ocean blue model over the control gray model and would spend more time in that corresponding side of the tank, on average. We used a randomizer and Guppy Data Collector software to record over a trial of five minutes the collective time that five different male guppies spent with corresponding models. We found that our hypothesis was not supported, as on average, the male guppies spent more time in the side of the tank that contained the gray control model instead of the ocean blue experimental model, and were significantly more favorable to the left side of the tank (p=0.001). In future studies, the same hypothesis could be retested with a black experimental model instead, because of the possibility that the blue model was not as profound to the male guppies because of the blue background of the fish tanks. Different sizes of models could also be tested in the future, while tracking the different courtship behaviors of the male guppies in response to size.