Pectoral Fin Proportionality and Mating Behaviors in Male Guppies

Abstract

Throughout nature, many organisms show a preference in the opposite sex when choosing a mate for reproductive purposes including size, shape, color, and behaviors displayed. Another factor is proportionality, though it is not as commonly studied in many organisms, it is an important factor in both nature and society. Proportionality, the symmetrical attributes of an object that have an equal ratio between the physical parts, have been popular throughout time in society including visual art, music, beauty, and in nature. Because of the effect that proportionality has had a effect throughout the history of humans, we were wondering if the beauty that human eyes see in proportionality could possibly be shared with other organisms through preference in selecting a mate. We are specifically interested in the effect of proportionality of pectoral fins on female guppy models on the amount of male guppy mating behavior observed. Male guppies choose female mates based on a variety of factors, including size, shape, and color. This was tested through an experiment where we watched the number of mating behaviors a male guppy displayed to different 3D models of female guppies within five-minute time increments. Our results displayed an increase on average in the amount of mating behaviors toward more proportional mates, but didn’t display a significant difference in proportionality preference; therefore showing our hypothesis to be unsupported. Alternative explanations can be made to explain out findings and further research is needed in order to reach a firmer grasp on the relationship between symmetry and mate selection.