Respiratory response of fifth-instar codling moth (Lepidoptera: Tortricidae) to rapidly changing temperatures

Fifth-instar codling moth, Cydia pomonella (L.), larvae were exposed to 10 simulated heat treatments of apples and pears and CO2 levels were monitored as a measure of respiration. Marked increases in respiration rates (microliter CO2/mg/min) were noted during these treatments. Respiration peaked between 3.5 and 4.8 microliters CO2/mg/min; the amount of time to peak respiration depended on the heating rate and was correlated to the LT95. No differences were observed between male and female larvae in the timing of the peaks of CO2 production. In treatments where mortality occurred, CO2 levels dropped to zero, but only after a considerable time after death. Respiratory recovery rates, the time it took for CO2 levels to return to normal, were recorded after treatments at time points where CO2 production reached 3/4 and maximum peak. Respiration rates at constant temperatures were recorded within the range of 10-30 degrees C. Q10 over this range was 1.49, whereas Q10 was the greatest, 2.54, between 10 and 15 degrees C.