In the Australian frog Crinia georgiana, matings frequently involve a single female and multiple males (group spawning). The aim of the present study was to demonstrate a connection between variation in the intensity of intrasexual competition, measured by using male density and operational sex...

Socially monogamous species vary widely in the frequency of extrapair offspring, but this is usually discussed assuming that females are free to express mate choice. Using game-theory modeling, we investigate the evolution of male mate guarding, and the relationship between paternity and...

Brood desertion involves a series of interactions between the members of a pair. This process is likely to be based on either member's perception of the other's propensity to desert. We manipulated this perception in males by experimentally increasing female body mass in the rock sparrow...

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...

Recent studies have documented male traits that cause physical harm to their mates during copulation. Such harm has been suggested to either (1) arise as a negative pleiotropic side effect of adaptations that give males a reproductive advantage in another context or (2) represent a male...

Males of the bruchid beetle Callosobruchus maculatus have spines on their intromittent organs that puncture the female reproductive tract during mating. Females kick their mates during copulation. If females are prevented from kicking the males, copulations last longer and the injuries females...

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...

Sexually transmitted diseases play a potentially important role in the ecology and evolution of host mating behavior. Here, we use a sexually transmitted nematode-cricket (Mehdinema alii--Gryllodes sigillatus) system to examine the effects of parasitism on host mating activity and female choice....

In the majority of socially monogamous bird species, females solicit or accept copulations from males other than their partner. Females may gain direct benefits from extrapair males, such as greater access to resources, or indirect genetic benefits that will influence the future success of their...