Male competition is disruptive to courtship in the Pacific blue-eye

The present study examined the effects of competition on male courtship in the Pacific blue-eye Pseudomugil signifer, a species of fish where females have previously been shown to use courtship, but not male fighting prowess, as an important mate choice cue. Courtship bouts directed to a stimulus female were shortest when two males were allowed to freely interact (contact treatment) and longest when there was only one male (non-interaction). Courtship length in trials where one of two males was confined to a clear cylinder (visual) was intermediate between the other two treatments. Courtship in visual and contact treatments was constantly disrupted. The percentage of interrupted courtships was higher for the contact compared to visual treatment where aggressive interactions were also longer in duration and took place more frequently. Within contact trials, dominant males courted longer than subordinates despite both males experiencing comparable rates of courtship disruption. These results suggest that male-male competition can have important implications for adaptive female choice particularly in circumstances where the benefits being sought by females are unrelated to male fighting ability.