Abstract
When newly eclosed or mature flies from a culture stock at 21°C of the 1(3) ecdysone-1st mutant of D. melanogaster are transferred to 29°C, two harmful events appear to be outcomes of the high temperature and not related to the mutation per se: a steady decrease of lifespan—a sudden drop in the male fertility 7 days after the temperature shift. When newly eclosed or mature females are transferred to 29°C and mated with fertile males, various ovarian dysfunctions express the mutation syndrome within a few days: in the germaria, occasional defects in the formation of some follicles, e.g. abnormal numbers of cystocytes or/and lack of oocyte differentiation—more commonly and chiefly in midstage egg chambers, death of nurse cells and certain follicle cells, failure of vitellogenesis, then oocyte degeneration—in late stages, abnormal deposition of yolk inclusions and aberrant formation of the eggshell layers. The result is a drastic drop in egg laying and hatching: when mature flies are transferred to 29°C, almost all the laid eggs are abnormal and abortive 4 days later. In spite of those conspicuous defects, ovarian proteins continue to be synthesized even 10 days after the shift, but at a lower rate.