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.

Do female association preferences predict the likelihood of reproduction?

“…This could be the result of differences between long-and short-sworded males in fertility (sperm and ejaculate quality and/or quantity) or the ability to coerce females into mating (female poeciliids are not in complete control of mating (Houde 1997;Bisazza et al 2001)). Although controlling for male size should help to control for variation in sperm and ejaculate quantity, it is possible that males with longer swords are in better condition and thus produce ejaculates of better quality (for example sperm with less damage).…”

Consequences of thermal acclimation for the mating behaviour and swimming performance of female mosquito fish

“…As the length of male deprivation increased, the likelihood that females were inseminated in the 48 h following male reintroduction also increased, even though all mating attempts were coercive and females were never observed to cooperate (Pilastro et al 1997). When deprived of males, female G. holbrooki possess reduced sperm stores and exhibit an increased tendency to associate with males (Bisazza et al 2001;Pilastro et al 2003). Additionally, the behaviour of non-deprived females that had just given birth was found to be indiscernible from male-deprived females when males were introduced to the observation tank (Bisazza et al 2001).…”

“…Additionally, the behaviour of non-deprived females that had just given birth was found to be indiscernible from male-deprived females when males were introduced to the observation tank (Bisazza et al 2001). These studies suggest that female mosquito fish associate more often with males when sperm stores are reduced and when received sperm is likely to be used soon after in the fertilization of new ova (Bisazza et al 2001). While females never appear to cooperate with mating attempts, results from our study along with previous research on virgin female G. holbrooki suggest females may play a greater role in the success of coercive mating attempts than previously considered.…”

Females prefer to associate with males with longer intromittent organs in mosquitofish

“…The sexes were housed separately: 45 females per 120 l aquarium and 10 males per 6 l aquarium. Females were male-deprived for 4-6 weeks to increase sexual receptivity (Bisazza et al 2001). Fish were kept at 288C with a 12 : 12 h photoperiod and fed live Artemia and fishflakes ad libitum.…”