Reduced adiposity is a phenotype that, although also consistent with one of the classic symptoms of type I diabetes in humans, had not previously been observed in flies with a ubiquitous reduction in insulin signaling or lacking the systemic Ilp peptides (puzzlingly, these flies were actually found to accumulate triglyceride; Böhni et al., 1999, Grönke et al., 2010). Here, INS is linked to type 1 diabetes mellitus.