[The influence of diurnally alternating temperatures on the pink bollworm Pectinophora : II. The oxygen consumption].

The oxygen consumption was studied in last instar larvae of the pink bollworm Pectinophora gossypiella, which had been reared in various constant and diurnally alternating temperatures.Larvae bred in constant temperatures showed no circadian pattern in the metabolic rate. The respiration of larvae which were adapted to alternating temperatures changed with the temperature cycle, but no metabolic rhythm was observed in these larvae when the oxygen uptake was measured in a constant temperature for about 24 hrs.Within the temperature range of 26-30°C, the respiration was weight proportional. At lower and higher temperatures, however, the metabolic rate/weight ratio (O2=Kxweightb) increased with an exponent b greater 1.A temperature compensation, i.e. a relative independence of metabolic rate from temperature change, was not observed neither by adaptation of the larvae to constant nor to alternating temperatures.Together with results presented in part I of this study (Welbers, 1975), the data indicate that the metabolism of the pink bollworm operates with maximal efficiency in a narrow temperature range of about 26°C.