Temperature acclimation in Tribolium and Musca at locomotory, metabolic, and enzyme levels

Abstract

The results of this study indicate that metabolic acclimation precedes locomotory acclimation. The effect of acclimation on the two species varies with respect to enzyme (Mg 2+-activated ATPase) activity. Tribolium confusum shows acclimative differences in ATPase activity throughout its normal temperature range. Enzyme activity of warm-acclimated beetles transferred to a low temperature showed little acclimation after more than 900 hr at the new temperature. This suggests that a rapid acclimation of ATPase activity is not essential to this insect and, perhaps, that other mechanisms are more important. The ATPase activity of Musca domestica shows no substantial acclimative differences in the temperature range of 15 to 30°C, but, at low temperatures near the chill-coma temperature, acclimative differences are evident. These differences increase the insect's sensitivity to temperature and are similar to interspecific differences found with the same enzyme in other insects. The results of this study also suggest that the rate of acclimation to temperature is dependent on the thermal environment of the insect being studied. Insects that live in a relatively stable thermal environment, like T. confusum, seem to acclimate slowly. M. domestica, which lives in a highly variable thermal environment, acclimates more rapidly.