Meeting Abstract
Maturation is a critical life-history milestone that reflects a trade-off between age and size, with consequences for survival and lifetime reproductive success. Many ectotherms show female-biased sexual size dimorphism, often reflecting delayed maturation of females relative to males. Within each sex, variation in the timing of metamorphosis can be an important source of variation in fitness. We investigated maturation in the gray tree frog, Hyla versicolor, examining variation in age at maturity as a function of diet, sex and parentage. Maternal half-sibship offspring were reared to maturity in captivity under two dietary regimes. Age at maturation was strongly related to sex, size and maternal identity. Males were smaller than females, grew more slowly and tended to mature earlier. While larger individuals were more likely to mature in the first year regardless of sex, early maturation in females was more strongly associated with reaching a larger size. Genetic variation in post-metamorphic growth contributed to variation in maturation through its effects on body size, but maternal effects alone influenced on the propensity to mature at a given size. Thus, we found no evidence of genetic variation in the trade-off between age and size at metamorphosis in our study population. Our results reveal sex differences in growth and development, with females not only delaying maturation but also growing more rapidly both before and during maturation. These differences in the ontogeny of sexual size dimorphism may relate to the evolution of different tactics to optimize lifetime fitness in this species.
