In flies and other insects, starvation delays metamorphosis from larval to pupal stages, but once a certain size or weight - the critical weight - is reached, development proceeds independently of nutrition. What regulates this switch? On p. 2345,Christen Mirth and colleagues report that in Drosophila wing imaginal discs, it is ecdysone molting hormone signalling. They show that the expression of wing-patterning proteins is suppressed when larvae are starved pre-critical weight, but that this expression becomes nutrition-independent thereafter. Increasing the size of the prothoracic gland, which produces ecdysone, pre-critical weight through enhanced insulin signalling during starvation leads to premature nutrition-independent wing-patterning protein expression; suppressing insulin signalling delays it. Knocking down the ecdysone receptor (EcR) in the wing disc, which leads to the derepression of transcriptional targets normally repressed by unbound EcR, also results in premature nutrition-independent patterning protein expression. Together, these findings reveal that ecdysone signalling switches wing disc development to a nutrition-independent mode by derepressing genes that are repressed by unbound EcR.