Umsatz und Transport der Nährstoffe bei Dixippus morosus im Zusammenhang mit Wachstum und Metamorphose

Abstract

Growth rates of midgut and fat body, as well as total growth occurring in the course of the last larval instar and in the early adult of Dixippus morosus, were correlated with alterations in protein, fat, glycogen, and chitin content in the respective tissues. Changes in the dry weight of these organs parallel changes in fresh body weight. This correspondence, however, does not apply for all chemical constituents studied, e.g. the fat content of the midgut and protein content of the fat body. The glycogen content of the midgut remains at a relatively steady level. In the fat body, however, it undergoes great changes, being increased many times in the course of the instar and then rapidly dropping from the beginning of apolysis. The concentration of blood proteins increases continuously; the sharp decline which follows during the last period of the instar slows down in the adult. The carbohydrate concentration increases only temporarily with the initiation of apolysis, probably because of the release of carbohydrates from the fat body. The chitin content of the integument grows throughout the first half of the instar, then levels off, and decreases gradually until the ecdysis. Breakdown products of chitin from the old cuticle are apparently re-used for the newly secreted cuticle. The fall in the carbohydrate content in the gut, fat body, and haemolymph is probably due to the utilization of sugars as a source of energy rather than as precursors for chitin synthesis. During the larval-adult apolysis and ecdysis, there is a simultaneous enhancement of reserve utilization, in particular of protein from midgut wall and haemolymph, and of carbohydrates and fat from the fat body.