Parameters for growth of the imaginal wing disk in last instar larvae of Galleria mellonella L

Abstract

In last instar larvae of Galleria mellonella, the observed increase in the number of cells of growing intact imaginal wing disks was completely blocked by ligation of the mesothorax and stimulated again by external applications of low and high doses (2.6 to 130 Kglg) of ecdysterone. However, at no hormonal dose applied has the full extent of normal wing growth been attained. The ecdysteroid dependent cuticle synthesis could be induced in disks of various sizes. The cell number of imaginal disks of young last or supernumerary instar larvae is exponentially correlated with the body weight. The rates of cell division during prepupal development of the wing disk appeared to be about the same in last and supernumerary instar larvae.In normal pupae the borders of the everted wings are fitted precisely to a cuticular demarcation line on the underlying abdomen. X-ray irradiations of last instar larvae led to a reduction of the pupal wing surface and cell number, but did not affect the position of the demarcation line. The X-ray experiments confirm the finding that reduced wings are capable of normal pupal cuticle synthesis.

“Reduced appendage”: A mutation affecting development of pupal and adult appendages of the moth, Plodia interpunctella

“…The forewing imaginal discs of the wild-type pharate pupa from P. in terpunctella contained approximately 65,000 cells, which was similar to the number of cells observed in the hind wing imaginal discs from E. kuhniella (Pohley, 19561, a closely related pyralid moth of similar size. The rate of increase in the cell number, and therefore the relative size, of the wing imaginal discs from P. interpunctella wild-type strain was similar to that observed for other lepidopterans (Pohley, 1956;Williams, 1980;Kurushima and Ohtaki, 1975;Meyer et al, 1980;Kawasaki and Iwashita, 1987).…”

“…The number of cells in the imaginal discs can be reduced experimentally by inducing cell death. By exposing last instar larvae of the moth, Galleria mellonella, to X-rays, small pupal wings were induced (Meyer et al, 1980). The smaller size of the wings was the result of a reduction in the number of cells present that comprised the pupal wings.…”

Imaginal cell-specific accumulation of the multicatalytic proteinase complex (proteasome) during post-embryonic development in the tobacco hornworm,Manduca sexta

“…During the Vth (ultimate) larval stage in M. sexta, the epithelial cells of the wing discs undergo extensive proliferation that leads to a n at least tenfold increase in length and a fourfold increase in width (Pohley, 1959;Meyer et al, 1980;Nardi et al, 1985). The mitotic rate is highest after the onset of wandering.…”

The 20-hydroxyecdysone-induced signalling pathway in G2/M arrest of Plodia interpunctella imaginal wing cells

“…In lepidopteran larvae, the rate of proliferation of the imaginal cells is fairly constant in the young instars. At the end of the last larval instar, however, many of the imaginal cells are blocked in the G2/M phase in response to the rising ecdysteroid titre preceding pupation (Kurushima and Ohtaki, 1975;Meyer et al, 1980;Oberlander, 1985;Fain and Stevens, 1982;Graves and Schubiger, 1982). This arrest coincides with the beginning of pupal differentiation of imaginal discs into adult organs to replace the larval counterpart.…”