Abstract
1. Oxygen consumption has been studied in cultures of nymphal and adult cockroaches, Peniplaneta americana, that have been maintained at two experimental temperatures (10° and 16° C.) and the control temperature (26° C.) for a period of one to three weeks. 2. It has been shown that the oxygen consumption of equal-weight nymphs when measured at 20° C. is higher in animals that have been maintained at the lower temperatures. 3. Comparison of cold- (10° C.) and warm-adapted (26° C.) nymphs when measured at a series of temperatures (10° to 25° C.) demonstrates that cold-acclimated animals consume more oxygen per gram per hour than equal weight warm-adapted ones. 4. Adult cockroaches show acclimation of their oxygen consumption to temperature. However, there isa differential response with respect to size; small adults acclimate to a greater degree than large ones. Further, all sizes of nymphs show a greater degree of acclimation than all sizes of adults.