SREL Reprint #2408

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

Christopher W. Beck1,2 and Justin D. Congdon1

1Institute of Ecology, University of Georgia, Athens, GA 30602, USA
2Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, USA

Abstract: We conducted two experiments with the southern toad (Bufo terrestris) to examine 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 the first experiment indicated that neither initial body size nor metabolic rate was related to survivorship or growth. Results from the second experiment showed that (i) size at metamorphosis was positively correlated with survivorship to first census (after 2 weeks), (ii) age and size at metamorphosis had no significant effect on survivorship from first to second census (after 2 months), (iii) size at metamorphosis had a marginally significant positive effect on survivorship from metamorphosis to second census, and (iv) age and size at metamorphosis were not significantly correlated with total growth. Our results suggest that in the southern toad, size at metamorphosis may lead to early differences in survival, size, and growth that later disappear. Furthermore, early differences in growth and survival attributable to size at metamorphosis are not due to size-related differences in metabolic rate. Therefore, although age and size at metamorphosis affect metabolic rate, they may not be related to fitness via effects on postmetamorphic survival and growth.

SREL Reprint #2408

Beck, C.W. and J.D. Congdon. 1998. Effects of individual variation in age and size at metamorphosis on growth and survivorship of southern toad (Bufo terrestris) metamorphs. Canadian Journal of Zoology 77:944-951.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).