[Autoradiographic studies on the oosome in the oocyte ofPimpla turionellae L. (Hymenoptera)]

During the longitudinal growth of the oocytes ofPimpla the voluminous oosome area has considerable amounts of newly synthetized proteins (= 1st stage of oosome formation). Short time incubations result in labelling the oosome area as distinctly as the plasm in the nurse cells, in spite of the considerable distance between nurse cells and oosome area. Thus there is no evidence of trophocytic proteins being transported towards the oosome. Consequently during the 1st stage of oosome formation more proteins are synthetized in the oosome area than in the ooplasm.All over the oocyte, oocytic and extra-oocytic components are adding to the propagation of ooplasm (intussusceptive growth). During the 1st stage of its formation, the oosome could possibly contain an additional system for appositional growth within the posterior part of the oocyte, or/and the proteins synthetized herein could play a part in the synthesis of fats. Further questions in connection with these preliminary hypotheses can be answered by more refined methods only. During the oocytic stages following the degeneration of the nurse cell chamber (= 2nd stage of oosome formation), the ever more ball-shaped oosome accumulates trophocytic RNA, which is present all over the rest of the egg space as well. This stable RNA is meant to serve either for the somatic embryogenesis or the germ line.Further autoradiographic observations of the ovarioles essentially confirm known facts concerning the extra-oocytic supply of the oocyte as stated for meroistic ovarioles. This includes the supply with stable and unstable RNA from the nurse cell chamber and proteins from haemolymph for vitellogenesis as well as nurse cell plasm rich in RNA, available during the degeneration of the nurse cell chamber.