Effects of Moulting Hormones and Prothoracic Glands on the Development of Wing Discs of the Cabbage Armyworm (Mamestra brassicae L.) in Vitro : Lepidoptera : Noctuidae

Abstract

The morphogenetic effects of ecdysterone at different concentrations and various numbers of prothoracic glands, on the wing discs of the cabbage armyworm (Mamestra brassicae L.) were studied in vitro. Wing discs developed rapidly at high concentrations of the hormone, but they degenerated early. At low concentrations of the hormone they developed slowly and visible morphogenetic changes occurred about 9 days after the onset of the culture. The activities of 5 kinds of moulting hormones assayed by Mamestra wing discs ranged as follows : ponasterone A≓cyasterone≓ecdysterone>ecdysone>rubrosterone. Similar phenomena were observed when wing discs were cultured in the presence of prothoracic glands of Mamestra. The period before initiation of development of the wing discs was shortened with an increase in the number of prothoracic glands, but they degenerated quickly. On the other hand, in cultures with a moderate number of prothoracic glands, the wing discs developed as well as in vivo.