Abstract. Changing temperature regime has an important effect on the respiratory metabolism of Glomeris balcanica. A left skewing response of animals to increasing temperature is revealed and modeled. Acclimation from fluctuating to constant temperatures depresses metabolism through a three-step process. Short-term acclimation results in strongly depressed metabolism, mid-term acclimation induces metabolic recovery, whereas long-term acclimation results in an irreversible decline of metabolic activity. Heavy metal burdens of food do not affect the left skewing thermal response of animals, although they depress metabolic levels at the high temperature range, shorten tolerance ranges by shifting down the upper tolerance threshold, enlarge optimal temperature range (metabolic constancy) and stimulate the faster activation of the metabolic compensatory mechanism. Finally, no effect of short-term fasting on respiration was detected.