In1(3) ecdysone-1tsmutants ofD. melanogaster, multiform ovarian dysfunctions appear within a few days when mature flies are transferred from 21 to 29°C. (i) In germana, abnormal organization of the germ-line cells may be expressed by the lack of oocytes and/or aberrant numbers of nurse cells, (ii) In previtellogenic egg chambers, the fate of somatic cells (follicular epithelium) is varied, some of them become very thin, whereas others degenerate, (iii) In more advanced chambers, vitellogenin incorporation and yolk deposition fail to start in some oocytes whereas associated nurse cells continue growing.