In Sickness and in Health: Diseased Appearance and Effect on Male Mating Choice

Abstract

Sexual selection and mating preference occur among a wide variety of species, and is a type of
natural selection that results from a variation in the ability to acquire and obtain mates. Mating
choice is influenced by factors such as color, size, and overall health. We conducted an
experiment in order to explore how male mating choice is affected by diseased appearance. To
observe this, we placed a single male guppy in a fish tank containing an orange female model
and an orange female model with white spots, to mimic the common disease Ichthyophthirius
multifiliis in fish, and recorded the amount of time the male guppy spent with each model, along
with specific mating behaviors. The data collected shows a trend that supports our original
hypothesis – that the diseased experimental model will be less attractive to the male than the
control because of the parasitic appearance. However, after running the Wilcoxon signed-ranked
test to observe if our data was significant, the results showed that it was not. We believe that if
more trials were conducted the test results might differ. Further studies could be conducted on to
increase the sample size and see if this affects the outcome. This research is important because it
furthers understanding of aquatic life and breeding behaviors.