Female reproductive success in a fish with a coercive mating system (Gambusia affinis)

Authors: Rachel E. Martin, James C. II Cureton, Chad C. Hargrave, Raelynn Deaton

Year: 2008 (xl)

Abstract

The Western mosquitofish, Gambusia affinis, is known to force copulate with females and thus serves as a model organism for testing sexual selection in coercive mating systems. In this species, much is known about the males’ role in mating; however, how much control females have over male mating success or her own reproductive fitness remains untested. We tested for correlations between male mating behaviors and female fitness, and whether females have behavioral control over their own reproductive success. We also tested if more time spent with a male (30-min vs. 24-hrs) would lead to increased fecundity. Female receptive behaviors were correlated with both male unsuccessful and successful copulations, and female resistant behaviors were correlated with male unsuccessful copulations. There was no difference in female fecundity between two time treatments. Females were largely unreceptive to coercive males, as expected, and more receptive to less coercive males. Male reproductive success (measured as successful copulations) was not dependent on female behaviors; however, males harassed less than expected (in terms of unsuccessful copulation attempts) when females were receptive, suggesting that males obtained more successful copulations with receptive females. In addition, males harassed more than expected when females were unresponsive, and thus, not resistant. Results suggest that, although male coercive behaviors appear to be the most important factor predicting both male and female reproductive success, female mosquitofish do have some level of behavioral control over their own reproductive fitness.