Males may allocate a greater proportion of metabolic resources to maintenance than to the development of secondary sexual characters when food is scarce, to avoid compromising their probability of survival. We assessed the effects of resource availability on body mass and horn growth of bighorn...

For species in which reproductive success is more variable in one sex than the other, the Trivers and Willard model (TWM) predicts that females are able to adjust their offspring sex ratio. High-quality mothers should provide greater investment to one sex than the other. Previous tests of the...

The Trivers and Willard model (TWM) predicts that for polygynous ungulates, females of high phenotypic quality should produce more sons than daughters, whereas females of low phenotypic quality should produce more daughters. Kruuk et al. showed that in red deer the TWM only applied when the...

Mating systems are well known to influence the dispersing sex, but the magnitude of the sex-biased dispersal has not actually been measured, whereas many theoretical predictions have been made. In this study, we tested a new prediction about the coevolution between natal dispersal and sociality...

For dimorphic species in which the variance in reproductive success of males is more pronounced than that of females, theories of adaptive variation in sex ratio predict that mothers should invest more heavily in sons than in daughters. By using harvest data from a forest-dwelling red deer...