Respiration of Abax ater (Coleoptera, Carabidae): a complex parameter of the energy budget

Respiration is quantitatively the most important element in the energy budg et of the ground beetle Abax ater. It was measured in a Gilson respirometer for all developmental stages (except for the eggs), taking as many paramet ers as possible into account. The standard metabolic rate (SMR) increased exponentially with temperature in the range 5-15 degrees C but no metabolic acclimation to temperature was observed. A single relationship was found between body mass and respiration for all t he active stages. Adult males regularly had a SMR slightly higher than did females, but the difference was seldom significant and may be explained by differences in body mass. At constant temperature SMR exhibited a daily cycle with two peaks occurrin g in the first half of the night and in the morning. It also exhibited an a nnual cycle with a maximum in the summer. SMR was up to twice higher than the basal metabolic rate (BMR), and the act ivity metabolic rate (AMR) of running individuals was two to three times hi gher than SMR. Respiration increased to twice SMR the day after a full meal owing to diges tion, and then decreased for three days. The respiratory quotient (RQ) of 0.72 suggested that mainly lipid molecules were oxidised in A. ater respiration. Measurements of respiration by gravimetry gave results that were close to B MR. Besides the classical relationships of respiration with temperature and bod y mass, this work showed the significant influences of digestion and mobili ty on respiration : taking them into account realistically required multipl ying SMR by a factor 2.3 during the active part of the annual cycle of A. a ter. This correction allowed balanced energy budgets to be obtained.