Ecdysones and imaginal disc development during the last larval instar of Pieris brassicae.

Ecole Normale Supérieure, Laboratoire de Zoologie, 46 rue d'Ulm, F-75230 Paris Cedex 05, France
Journal of Insect Physiology (Impact Factor: 2.5). 02/1977; 23(2):277-83. DOI: 10.1016/0022-1910(77)90042-7
Source: PubMed

ABSTRACT Ecdysone haemolymph levels and in vivo development of imaginal wing discs have been studied during the last larval instar of Pieris brassicae.During this period, β-ecdysone variations show two successive peaks, the first one related to the induction of wandering stage, and the second (main) one to pupal cuticle synthesis. The observed situation is very similar to that of Manduca sexta. Imaginal wing disc growth is composed of several genetically programmed steps that need the presence of ecdysone, but do not appear very closely linked to circulating hormone levels. It seems that ecdysone haemolymph peaks should be considered as periods where ecdysone levels are above a threshold value.

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