Distinct impacts of JH III and JHB₃ mediated by the insulin receptor upon Drosophila life span

Insulin signaling regulates juvenile hormone (JH) titer in adult Drosophila melanogaster, where longevity is subsequently modulated by JH. Drosophila adults produce two forms of JH: JH III and JHB₃. We find that mutants within specific domains of the Drosophila insulin-like receptor uniquely affect the hemolymph titer of JH III and JHB₃. While all these mutants are long-lived, the JH mimic methoprene and JH III can fully restore wild-type adult survival only in adults lacking JH III, not in those lacking JHB₃. Our results suggest that JH III and JHB₃ are differentially regulated by insulin-like signaling and have distinct effects on adult survival.