The influence of male age on reproductive success after a single mating has been explored widely; however, few studies have investigated whether quantitative or qualitative differences in male sperm are responsible for the observed patterns. Moreover, the role of male age on sperm competitive...

Control over copulation duration is a potentially important generator of sexual conflict that has received little empirical attention. The copulatory behavior of the bruchid beetle Callosobruchus maculatus may reflect a sexual conflict over copulation duration. Males have spines on their...

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...

Prior experience with conspecifics or essential resources, as well as physiological condition, can have important influences on an animal's reproductive behavior. While effects of experience and physiological state (such as reproductive condition) are generally treated separately in theoretical...

Female multiple mating selects for male adaptations that maximize fertilization success in a context of sperm competition. While male mating strategies usually reflect a trade-off between present and future reproduction, this trade-off is largely removed in systems where the maximum number of...

Male redback spiders twist their abdomens onto the fangs of their mates during copulation and, if cannibalized (65% of matings), increase their paternity relative to males that are not cannibalized. The adaptive male sacrifice hypothesis proposes that this increased reproductive payoff from a...

Mating strategies are to a large degree shaped by conflicts between the sexes, causing a rapid antagonistic coevolution of traits involved in reproduction. The view that sexual cannibalism represents a form of sexual conflict leads to the prediction of male traits that facilitate escape from...

To test if an increased sperm competition risk affects male behavior and mating decisions of both sexes, we performed two experiments using the sand goby, Pomatoschistus minutus, a nest-building fish with exclusive paternal care. In our first experiment, a nest-holding male, with a confined...

Studies of fertilization success have demonstrated that male effects are often a strong and important source of variation in P-sub-2 (the proportion of offspring that are fertilized by the second male to mate). More recently there has been emphasis on female processes that occur during and after...

In most cooperative breeders, dominants suppress the reproduction of subordinates. However, two previous studies of Neolamprologus pulcher, a cooperatively breeding cichlid fish, have suggested that socially subordinate helper males sneak fertilizations from dominant breeding males. If such...