Standard energy metabolism of a desert harvester ant Pogonomyrmex rugosus: Effects of temperature body mass group size and humidity

摘要

Pogonomyrmex rugosus (Hymenoptera: Formicidae) is an important seed predator in the Mojave Desert of the southwestern United States. Its standard rate of O2 consumption (˙Vo2) varied significantly with temperature (˙Vo2 = 10^{(-1.588 + 0.0315T)}, where ˙Vo2 is ml·g^-1·hr^-1 and T is body temperature in °C). The ratio of the ˙Vo2 values at 10°C increments in body temperature, Q10, also varied with temperature; methods of calculating ˙Vo2 from temperature with a shifting Q10 are described. ˙Vo2 also varied with body mass (˙Vo2 = 0.0462M^0.669, where ˙Vo2 is ml·hr^-1 and M is body mass in g). ˙Vo2 was inversely related to relative humidity and was independent of group size. The rise in ˙Vo2 at low relative humidities was caused by increased activity and resulted in higher rates of net water loss. The primary metabolic adaptation to xeric conditions in P. rugosus appears to be a lower-than-predicted metabolic rate.