INDUCTION OF METAMORPHOSIS BY ECDYSONE ANALOGUES:DROSOPHILAIMAGINAL DISCS CULTUREDIN VIVO

The effects of molting hormone on the development of imaginal discs of Drosophila melanogaster were investigated. Imaginal leg discs from mature larvae were transplanted into the abdomens of fertilized adult female flies. The hosts were injected with a solution of a phytoecdysone—ecdysterone or cyasterone. The results showed: (1) Large doses of ecdysterone (over 1200 µg/g= 1.2 µg/fly) caused complete metamorphosis of the transplanted imaginal disc, including eversion of the disc, formation of a pupal cuticle, and formation of adult cuticle with bristles, hairs and sensilla arranged in normal orientation. (2) Ecdysterone was necessary as a sustained stimulus, and did not act merely as a trigger to metamorphosis. (3) Cyasterone was a more potent molting hormone than ecdysterone. The technique promises to simplify investigation of pattern formation and other developmental problems in Drosophila.