The Effect of Visible Disease (Ichthyopthirius multifiliis) on Male Guppy (Poecilia reticulata) Mating Choice

Abstract

Guppies (Poecilia reticulata), like most animals, choose mates based off of fitness.  Visible signs of disease or infection typically deter potential mates.  Guppies are commonly susceptible to parasites such as Ich (Ichthyopthirius multifiliis), which is visibly shown with white spots all over the body.  In our experiment, we tested the mating preferences of naïve male guppies between a female control model and a female model with Ich.  We hypothesized that the male guppies would prefer the female model with no visible signs of Ich due to its ideal fitness.  Our data did not support our hypothesis.  The male guppies spent the majority of their time on the control side of the tank, but only presented courtship behaviors to the Ich model.  We believe that differences in immunities and stress levels between the males as well as their naivety could have affected our results.