Fig. 2. Cold food stimulates a rapid increase in PPMR. Here for a D. gibsoni individual the time course of postprandial metabolic rate (PPMR) after a cold meal (food temperature, T_f=0°C, grey) is compared with that of PPMR after a similar sized meal at T_f=40°C (black). RMR is the resting metabolic rate prior to feeding, and opening the chamber at feeding time causes the apparent rapid fall in MR from an inrush of ambient air. As a result, measured PPMR rise times require correction for respirometer chamber characteristics and for this individual are estimated to be 2.2% less than those shown.