of age and size at metamorphosis on performance and metabolic rates of
Southern Toad, Bufo terrestris, metamorphs
C. W. Beck1,2 and J. D. Congdon2
of Ecology, University of Georgia, Athens, GA 30602, USA
2Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802,
1. Southern Toad, Bufo terrestris, tadpoles were reared at
two temperatures and two food levels in a 2 x 2 factorial design. Effects
of treatments on age and size at metamorphosis, metabolic rate (MR), sprint
speed and endurance of metamorphs were measured.
Across all treatments, MR, sprint speed and endurance were negatively
related to age at metamorphosis and positively related to mass at metamorphosis.
Therefore, decreases in larval period duration and increases in mass at
metamorphosis may be advantageous in terms of locomotor performance, but
disadvantageous because of the cost of increased energy expenditure on
maintenance, all else being equal.
After removing the effects of age and size at metamorphosis, neither of
the treatments nor their interaction significantly affected locomotor
performance. In contrast, MRs of metamorphs were significantly affected
by the interaction between the food and temperature treatments, independent
of age and size at metamorphosis. Thus, aspects of the larval environment
may affect metamorph physiology, and possibly fitness, via mechanisms
other than differences in age and size at metamorphosis.
Aerobic metabolism, complex life cycles, larval environment, larval period
W., and J. D. Congdon. 2000. Effects of age and size at metamorphosis
on performance and metabolic rates of Southern Toad, Bufo terrestris,
metamorphs. Functional Ecology 14:32-38.
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