Does Size Matter? The Effect of Body Size on the Mating Preferences of Poecilia reticulata.

Abstract

Guppies, Poecilia reticulata, are used as a model by researchers to better understand the mating behaviors and sexual selection of fish. Sexual selection is important for understanding mating systems and strategies as well as evolutionary bahaviors. Both male and female guppies show sexual preference while chosing a mate.  Many physical attributes influence selection including color, fin size, fin shape, and body size. In this study, we focus on male preference of female size. We hypothesized that male guppies will show preference towards larger females. In this lab, data was sourced from the Center of the Study of Sexual Selection in Fishes (CS³F 2021) as we had no access to actual guppies. We focused on the data collected from studies comparing the time males spent with small females (003, 36mm) versus the control model (001, 40mm), and the time spent with large females (002, 44mm) versus the control model (001, 40mm). By analyzing those trials we found that male guppies showed no real preference towards either the smaller females or the larger females. Males spent more time with 001 when compared to 002, and 003 when compared to 001. But this was shown to be statistically insignificant through use of the Mann-Whitney U Test. This allows us to conclude that male guppies have no preference for varying female body sizes.