Female preference and fitness benefits of mate choice in a species with dissociated sperm transfer

Female mate preference can have important fitness consequences for females through direct or indirect benefits of mate choice. However, the existence and benefits of mate choice in species that perform dissociated sperm transfer is largely unknown. In the springtail Orchesella cincta, receptive females locate and take up spermatophores deposited in the litter layer by males, without even meeting their partner. We investigated female sexual selection and its benefits in O. cincta. We performed female choice trials with manipulated spermatophore density and diversity to assess female preference for different spermatophore deposition patterns. Furthermore we tested whether females benefit from choosing between spermatophores by measuring several reproductive variables of females assigned to single male (no choice) and double male (choice) mating treatments. Our results show that females chose patches with four spermatophores over patches with a single spermatophore, but did not discriminate between patches of three spermatophores from a single male or from three different males. The mating experiment showed that O. cincta females gained indirect benefits from choosing between spermatophores of different males, because male offspring resulting from the double male treatment produced more spermatophores than the male offspring from females without a choice. No evidence was found for direct benefits of female choice, because there were no differences in clutch size, egg size or offspring survival between treatments. Despite the large number of studies on female mate choice, this is the first time that indirect benefits have been demonstrated in a species with dissociated sperm transfer.