The effect of nitrogen starvation on Tenebrio molitor L

Half-grown larvae of the mealworm, Tenebrio molitor L., were deprived of nitrogen during 4 weeks either by feeding glucose alone or by feeding cellulose alone, and were used for several analyses and enzyme assays. Glucose-fed larvae increased their body weight slightly, but the efficiency of the diet, expressed in weight increase per g ingested, was low compared to larvae on a complete diet. Starved larvae lost weight mainly by utilizing glycogen and fat, whereas glucose-fed larvae increased glycogen and fat deposition. Glucose-fed larvae contained a higher portion of ether-extractable nitrogen than normal and starved larvae and excreted more uric acid than starved ones. The rate of respiration was highest in the glucose-fed larvae and lowest in the starved larvae. Furthermore, glucose-fed larvae showed a higher RQ value and a higher rate of cyanide-sensitive respiration than larvae on the control diet. The particulate fraction prepared from glucose-fed larvae exhibited an increased activity for cytochrome oxidase and succinic dehydrogenase, and an increased rate of oxidation of TCA cycle members. Lactic dehydrogenase activity was also increased in total homogenates prepared from these larvae. However, these hormogenates exhibited a highly reduced tyrosinase activity.