Larva imaginal disc

This mode of regulation seems appropriate to the ERTs since their cells are already terminally differentiated, and their primary function is to grow and provide a nutrient rich incubator for the undifferentiated neuroblasts and imaginal cells that eventually produce the reproductive adult. The response of these undifferentiated progenitor cells to food withdrawal is quite unlike that of the ERTs. Larval neuroblasts and imaginal disc cells continue to proliferate for many days after a larva is starved, and seem to complete their normal proliferation programs. In this instance the ERTs lose mass, presumably as they transfer stored nutrients to the developing nervous system and the discs. 

Edgar The larva is a fully functional animal made up of terminally differentiated cells, but its purpose is to be an incubator for these imaginal discs that make the fly. It has to bulk up on mass and it transfers this biomass to the discs as they grow. I think it is a really simple way for an organism that is already differentiated to grow. It is a sort of stripped-down cell cycle that can respond to nutrition. There is no need for those cells to proliferate. 

Drosophila melanogaster (the fruit fly) is used in two ways Larvae are grown on feed containing the test agent, are allowed to pupate, and emerging adults are scored for viability (toxicity) and malformations from alterations in imaginal discs present in the larvae and used to form adult structures or early primary embryonic cell cultures are grown in... 

Effects of brassinosteroids on imaginal discs isolated from two different fly species (Phormia terraenovae, 15 Calliphora vicina, 16, 17) were observed. As expected, the imaginal discs of Phormia and Calliphora larvae evaginated in response to 20-hydroxyecdysone. 

Figu re 10.1. Schematic representation of late third-instar larvae, showing the approximate locations and shapes of the imaginal discs. (Reprinted, with permission, from Bodenstein 1950.)... 

To remove the eye-antennal imaginal discs from the larva (Figures 12.IB and 12.3A), use one pair of forceps to gently hold the larva at approximately one third of its length from the interior end. With a second set of forceps, grab a firm hold at the base of the mouth hooks and then pull the mouth parts away from the rest of the body (Figure 12.lA). 

Figure A2.9. Position of the trachea, imaginal discs, and abdominal histoblasts in the larva. (Redrawn, with permission, from Poodry 1980.)...

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