Let Me Show You A Few Things: Effect of Mate Size on Male Guppy Sexual Behavior

Abstract

Guppies (Poecilia reticulata) are a common model organism for the study of the paradox that can exist between natural selection and intersexual selection due to dimorphism and male variations in color (French, 2016). We hypothesized that male guppies will sexually select the larger 3D printed female model more than the 3D printed control female model because overall size in females is a prediction of higher fecundity, which is an indication of female fitness (Branz et al. 2016). We tested this hypothesis by presenting the two models to the male and observing both the amount of time the male spent in either of the preference zones in addition to the number of different types of sexual behaviors in each of the five trials. We found that while the guppy spent more time in the No Choice Zone, he did indeed exhibit, on average, more of each type of sexual behavior, with the exception of biting, towards the larger experimental model, which supported our hypothesis. This has implications that both male and female guppies choose mates with the highest fitness.