DIRECT SELECTION ON MATE CHOICE - FEMALE REDLIP BLENNIES PAY MORE FOR BETTER MATES

Sexual selection may be reduced by costs of mate choice such as predation risk and energetic expense. Despite their theoretical importance, such costs have rarely been quantified or related to the quality of mate obtained. We performed such a study with a wild population of redlip blennies in Barbados. In this coral reef fish, females traveled 0.2-12 m from their feeding territories to the territories of nesting males, where they spawned and left their eggs in the males' care. Previous studies have shown that larger and older males are better parents and are preferred by females. Here, we found that long-distance trips by females were made primarily toward larger males, and the extra distance traveled beyond the nearest male was correlated with the improvement in size of male obtained. Comparisons with feeding budgets while the females remained on their home territories suggested that costs from lost time and energy were minor, and no predation attempts on females were observed. However, on longer trips the females faced more aggressive attacks from damselfishes, whose territories they crossed. In contrast, no attacks were observed from damselfish when the blennies remained on their own territories. These attacks appeared to be responsible for a greater incidence of scars on females than on males. This difference between the sexes became more pronounced as spawning progressed, and then decreased as females healed during the nonspawning interval. Thus, female blennies endure a cost of interspecific harassment which is correlated with the quality of mate obtained. This cost may restrain sexual selection in this species.