TEMPERATURE EFFECTS ON METABOLISM, VENTILATION, AND OXYGEN EXTRACTION IN A NEOTROPICAL BAT

We examined the relationship between ambient temperature (Ta), body temperature (Tb), oxygen consumption (V̇O), carbon dioxide production (V̇CO), evaporative water loss (ṁH2O), respiratory frequency (f), tidal volume (Vt, minute volume (V̇i), and oxygen extraction (EO) in the Neotropical bat Noctilio albiventris (mean mass 40 g). The factorial aerobic scope was 7.2 between Ta of 1-35°C ( V ̇O=0.119 and 0.0165 ml/(g·min), respectively). The respiratory exchange ratio (V̇CO/V̇O) did not change with T and ṁH2O was constant between Ta of 10-35°C. Thermal conductance was minimal at 30°C and constant and low at Ta < 30°C. Between 10 and 35°C, Noctilio accomodated changing V̇O with parallel and roughly equivalent changes in f, Vt, and EO. The change in V̇O between 10 and 1 °C was accomodated mainly through changing f. Ventilation parameters in resting thermoneutral Noctilio are intermediate between allometric values for birds and mammals. Maximal EO in Noctilio (35-40%) is higher than for other mammals but considerably less than maximal EO in some birds. © 1990.