Abstract:
In polygynous species, variance in reproductive success is higher in males than females.
There is consequently stronger selection for competitive traits in males and early growth can
have a greater influence on later fitness in males than in females. As yet, little is known about
sex differences in the effect of early growth on subsequent breeding success in species where
variance in reproductive success is higher in females than males, and competitive traits are
under stronger selection in females. Greater variance in reproductive success has been
documented in several singular cooperative breeders. Here, we investigated consequences of
early growth for later reproductive success in wild meerkats. We found that, despite the
absence of dimorphism, females who exhibited faster growth until nutritional independence
were more likely to become dominant, whereas early growth did not affect dominance
acquisition in males. Among those individuals who attained dominance, there was no further
influence of early growth on dominance tenure or lifetime reproductive success in males or
females. These findings suggest that early growth effects on competitive abilities and fitness
may reflect the intensity of intrasexual competition even in sexually monomorphic species.
