Ali, A.K., R. Primicerio & I. Folstad. (2014). Female morphology and male mating success in the calanoid copepod, Eudiaptomus graciloides. Journal Of Plankton Research, 36(5):1216-1223;
In species exhibiting intersexual conflict over mating, the outcome of femalemale sexual encounters may depend on the phenotypic value of traits of either sex that are important for precopulatory behaviors. To explore this prediction, we investigated the relationship between female morphology and male mating success using mate choice experiments in the diaptomid copepod, Eudiaptomus graciloides (Lilljeborg), where intersexual conflict seems to cause an accumulation of spermatophores among small, easily accessible females. Three randomly selected receptive females were combined with an adult male in small glass vessels containing filtered lake water. After an introduction period of 24 h, copepods were preserved for subsequent morphometric analyses. We examined whether measurements of the different body parts of the males, and the mated and the unmated females correlated with the female mating status/male mating success. The results suggest that mated females had relatively longer furca than unmated females, confirming observations from earlier field studies. Moreover, mated females had a smaller body size and a longer genital double somite compared with unmated females. The results of the experiment, that smaller easily captured females are those first mated, are consistent with predications generated by a model of a sexual conflict. Based on the behavioral sequence and the mechanics of copulation in this system, we discuss the influence of such traits on the observed outcome of mating interactions.