Fluctuation of protein granules in the fat body of the viviparous cockroach, Diploptera punctata, during the reproductive cycle

Abstract

Protein storage granules of the abdominal fat body of the adult viviparous cockroach, Diploptera punctata were identified histochemically and the relative numbers were estimated at intervals throughout the reproductive cycle of mated females and in virgin females and males of the same age. Granules were counted in sections of the fat body and alternately the total quantity of protein was determined by the Lowry modification of the Folin method after removal of uric acid. Protein granule storage is clearly correlated with the reproductive cycle of mated females. The granules disappear during vitellogenesis and reappear during the gestation period. Virgin females which mature eggs sporadically and much later than mated females show a cyclic depletion and repletion of granules related in pattern to that of mated females but about 30 days shorter. Males also show a depletion of granules at ecdysis, followed by a repletion. There was more variation among individuals of the same age in males and virgin females than there was in mated females during the first reproductive cycle. It is speculated that the juvenile hormone which is necessary for vitellogenesis also controls depletion of protein granules from the fat body.