Temporal dynamics of intersexual conflict and the effect of male quality on female fecundity in the marine isopod Cleantiella isopus

Abstract

Crustacean males grasp and/or guard females before copulation to ensure mating, but females typically resist males during pair formation. The benefit of resistance for females might allow (1) females to optimize mate quality, or (2) to avoid costs incurred during guarding. However, it has not been fully investigated which benefits actually improve female fitness. Here we investigated female resistance, temporal dynamics of intersexual conflict during reproduction, and the effect of male size and male mating frequency on female fecundity in the marine isopod,Cleantiella isopusto examine the relative importance of the two mechanisms mentioned before. Females resisted even after they had become receptive. Females which mated with small males showed lower fecundity than the ones with large males, and small males were frequently unable to form pairs. These results suggest that female resistance ofC. isopusagainst males can function as a way to optimize mate quality.