Effect of crude corpora cardiaca extracts on carbohydrate and lipid metabolism in larvae of the cerambycid beetle Morimus funereus as a function of diet and temperature

The effects of crude corpora cardiaca (CC) extracts on the changes in haemo lymph trehalose and lipid concentrations in larvae of cerambycid beetle Mor imus funereus were investigated as a function of diet and temperature. Afte r injection of crude conspecific CC extracts, haemolymph trehalose concentr ations were significantly increased in the last larval instar of M. funereu s reared on artificial diet at 23 C. In M. funereus larvae. injected with c rude brain extracts, haemolymph trehalose concentrations were increased by 15%, while glycogen concentrations were decreased by 17.5%. By injection of crude extracts of suboesophageal ganglion an increase was obtained in fat body glycogen concentrations. In larvae exposed to a stressful temperature of 13 degrees C for 90 min haemolymph trehalose and lipid concentrations we re significantly decreased compared to control. By injection of crude CC ex tracts of adult M. funereus, haemolymph trehalose concentrations were signi ficantly increased in beetle larvae fed on natural diet at a low temperatur e of 4 degrees C. A different efficiency of CC extracts of larvae and adult beetles was obtained as a function of temperature, the nutritive Value of the diet and the developmental stage. (C) 1999 Elsevier Science Inc. All ri ghts reserved.