Meeting Abstract
In many taxa, female mate choice has driven the evolution of elaborate male displays and ornamentation. There is evidence that females use these courtship displays, ornamentation, or both to assess a male’s quality. In aquatic animals, females may assess and select for the best, or most efficient, swimmers via courtship displays. Swimming efficiency indicates how much energy an individual uses to swim; more efficient swimmers use less energy at a given speed, allowing them to potentially swim longer. More efficient male swimmers may be able to last longer in courtship, demonstrating his quality to the female and out-competing other males in male-male competition. On the other hand, swimming efficiency may be honestly indicated by ornamentation and not courtship displays. Few studies have yet to conclusively link female preference to swimming efficiency. The objective of this study was to determine if females prefer males based on their swimming ability, morphology, or a combination of traits using Xiphophorus montezumae. X. montezumae males are distinguished from females by their “sword,” or elongated caudal fin. This species has been repeatedly used to assess female preference and male locomotor performance, but none have linked the two. We quantified male swimming efficiency by steady swimming energetics tests in a respirometer, and female preference by dichotomous preference tests. Male morphology was quantified by several metrics, including sword length. The results will be discussed in the context of previous work in this species and others on female preference and locomotor performance in relation to sexual selection.
