Energetics of vocalization in the African reed frog (Hyperolius marmoratus).

Rates of oxygen consumption and carbon dioxide release were measured in calling and resting painted reed frogs, Hyperolius marmoratus. O2 consumption increased linearly with call rate and reached 0.91 ml/g . h at average call rates of 3100 calls/hr. The respiratory quotient (RQ = VCO2/VO2) was calculated to evaluate which metabolic substrates--lipids or carbohydrates--are utilized. Males that were not fed for a week had significantly lower RQ's during calling (0.75) than recently fed males (0.89) and thus utilized approximately twice as much lipid to fuel calling. Whole-body lipid reserves of males collected in the field varied considerably. Lipid stores alone would be sufficient to provide energy for a median of 15 nights of calling activity at a high density chorus.