Mate choice for a novel male phenotype in zebrafish, Danio rerio

Abstract

Studies of mating preferences contribute to understanding the evolution of male secondary sexual traits. How females respond to novel male characteristics may lend additional insight into their mating preferences and subsequent mate choice patterns. Studies on several species have shown that females prefer males with manipulated or novel phenotypes. However, few studies have investigated the mechanisms that underlie female preferences. Adopting a relatively underutilized technology in studies of mate choice (genetic modification), we used transgenic zebrafish (Danio rerio) to evaluate female preference for normal versus novel transgenic (red GloFish™) males. We conducted four mate choice experiments in which females differed in rearing history to determine whether female mating preferences are influenced by population history, sexual imprinting or colour of food in their diet. We used a two-male association protocol in all four experiments as well as a one-male mating protocol in one experiment. In all four experiments, the association protocol demonstrated that females preferred novel transgenic males to normal males. The one-male protocol revealed no pattern of female mating preference; instead, mating patterns were strongly influenced by male coercion. Overall, our results suggest that zebrafish may possess a sensory bias for the colour red; however, more research using both closely related species and other colour morphs of GloFish™ are needed to resolve this issue. Our study exemplifies the utility of using transgenic organisms to study mate choice, and we propose that future studies incorporate this untapped technology.