The morphology of male genitalia often suggests functions besides sperm transfer that may have evolved under natural or sexual selection. In several species of sexually cannibalistic spiders, males damage their paired genitalia during mating, limiting them to one copulation per pedipalp. Using a...

Many sperm competition studies have identified copulation duration as an important predictor of paternity. This result is often interpreted as a sperm transfer effect--it is assumed that sperm transfer is limited by copulation duration. Here we test the assumption of duration-dependent sperm...