One hypothesis explaining extra-pair reproduction is that socially monogamous females mate with extra-pair males to adjust the coefficient of inbreeding (f) of extra-pair offspring (EPO) relative to that of within-pair offspring (WPO) they would produce with their socially paired male. Such adjustment of offspring f requires non-random extra-pair reproduction with respect to relatedness, which ...

In group-living species, the costs and benefits of group membership can vary with group composition (Krause & Ruxton 2002). Such effects are most evident when reproduction occurs in a social context. In cooperatively breeding species, participation in reproduction is typically biased towards a socially dominant breeding pair (reviews in Stacey & Koenig 1990; Taborsky 1994; Emlen 1997; Solomon &...

Polyandrous mating is common, but the benefits for females of polyandry remain controversial. To test whether mating with multiple males affects female fitness, we compared lifetime components of fitness of three experimental sets of Drosophila pseudoobscura females: monogamous females allowed to copulate one time (MOC); monogamous females held with a male over her entire life and experiencing ...

Mammalian imprinted genes are generally thought to have evolved as a result of conflict between parents; however, recent knockout studies suggest that coadaptation between mother and offspring may have been a significant factor. We present evidence that the same imprinted gene that regulates mammalian maternal care and offspring development also regulates male sexual behavior and olfaction. We ...

For dominant individuals in cooperatively breeding species, the presence of subordinates is associated with both benefits (i.e. increased reproductive output and other group-living benefits) and costs (i.e. intrasexual competition on reproduction). The biological market theory predicts that dominant individuals are tolerant to same-sex group members when there are only a few subordinates, so as...

Why do males in some species contribute to offspring care, while in others males have very little involvement with females and their offspring, beyond conception? This paper addresses this question using a combination of theoretical biology, genetic computation, game theory and data from living primates. Because of the heavy energetic demands of gestation, lactation and offspring care, studies ...

background: diminished libido and sexual dysfunction are unusually common among male epileptic patients. the most important etiologic factor may be antiepileptic drugs (aeds)-induced androgen deficiency. we compared reproductive hormone levels among men with epilepsy taking various aeds and normal controls. methods: subjects were 59 male epileptic patients who aged 24 ± 5 years. they had been r...

Life-history theory suggests that individuals should live until their reproductive potential declines, and the lifespan of human men is consistent with this idea. However, because women can live long after menopause and this prolonged post-reproductive life can be explained, in part, by the fitness enhancing effects of grandmothering, an alternative hypothesis is that male lifespan is influence...