vector metabolic process adult energy metabolism Energy metabolism starts when an insect ingests food, which supplies the fuel from which the chemical energy is liberated. Energy can be gained from lipids, carbohydrates, or proteins, but each one of these compounds cannot be used under every condition. The primary energy stores in insects are the fat body and the haemolymph. IDOMAL:0002162 IDOMAL:0002162 idomal_namespace