The origin of the nurse chamber in ovaries ofMiastor (Diptera: Cecidomyidae).

The nurse chamber inMiastor is a syncytium containing a variable number of nuclei. Many workers have claimed that all the nurse nuclei were derived from somatic cells. However, since one of these nuclei is larger than the remaining nuclei, other workers have thought that this nucleus was germinal in origin. Our ultrastructural studies of the nurse chamber-oocyte complex demonstrate the presence of an intercellular bridge between the nurse chamber and the oocyte. Furthermore, the large nurse nucleus contains lamellae characteristic only of the germ line. Both findings indicate that one of the nurse nuclei is the sister to the oocyte.