Female mate choice in a mating system dominated by male sexual coercion

Abstract

In poeciliid fishes, males can gain copulation either by courting females or through sexual coercion. In some species these two tactics coexist. However, in about half of the poeciliids, males do not display, females never cooperate during copulation and all matings are achieved by thrusting the intromittent organ toward the genital pore of apparently unaware females. In one of these species, the eastern mosquitofish (Gambusia holbrooki), the probability of insemination is influenced by the time females are previously deprived of males, suggesting that females exert some control over the occurrence of mating even in a system apparently dominated by sexual coercion. In the present study we investigated the tendency of female mosquitofish to approach males in relation to their reproductive status and the time they were previously deprived of males. The tendency to approach males increased in females that were previously deprived of males and in females that had recently given birth. When allowed to choose between males, male-deprived females preferred larger males and normally pigmented over melanistic males. Females preferred groups of three males over a single male, whereas the preference for three males over a group of one male and two females was only marginally significant. Collectively, these results suggest that, even when coercive mating is the only tactic adopted by males, females may be able to influence the outcome of these attempts, and thus exert some control over the paternity of their offspring. Key words: sexual selection, female choice, sexual coercion, Gambusia holbrooki, fish, mating tactics. [Behav Ecol 12:59–64 (2001)]