Cytochrome changes during honey bee flight muscle development

The progressive changes in the composition of the cytochrome system of the wing muscles during development through pupal stages and early adulthood in honey bees ( Apis mellifera L.) was studied in homogenates with a low temperature difference-spectrum technique. Cytochromes b 5 and a + a 3 are the only ones found during most of the pupal period. The association of this system with myofibril synthesis is discussed. Cytochrome b 5 abruptly becomes undetectable 2 days before emergence. Late pupal and early adult life is characterized by the progressive growth of cytochromes a + a 3, as well as the appearance and progressive growth of cytochromes b + c 1 and c. This growth parallels the growth of the specialized wing muscle mitochondria, the sarcosomes, and is completed 20 days after emergence. At this time the bee is capable of sustained flight, a faculty that is only gradually achieved during the sarcosome growth period. The association of the adult cytochrome system with the intense energy demand in the wing muscles during flight is discussed.