Effects of individual variation in age and size at metamorphosis on growthand survivorship of southern toad (Bufo terrestris) metamorphs

We conducted two experiments with the southern toad (Bufo terrestris) to ex amine whether individual variation in (i) metamorph body size and metabolic rate and (ii) age and size at metamorphosis were related to differences in survivorship or growth rate of postmetamorphic individuals. Results from t he first experiment indicated that neither initial body size nor metabolic rate was related to survivorship or growth. Results from the second experim ent showed that (i) size at metamorphosis was positively correlated with su rvivorship to first census (after 2 weeks), (ii) age and size at metamorpho sis had no significant effect on survivorship from first to second census ( after 2 months), (iii) size at metamorphosis had a marginally significant p ositive effect on survivorship from metamorphosis to second census, and (iv ) age and size at metamorphosis were not significantly correlated with tota l growth. Our results suggest that in the southern toad, size at metamorpho sis may lead to early differences in survival, size, and growth that later disappear. Furthermore, early differences in growth and survival attributab le to size at metamorphosis are not due to size-related differences in meta bolic rate. Therefore, although age and size at metamorphosis affect metabo lic rate, they may not be related to fitness via effects on postmetamorphic survival and growth.