Secreted Peptide Dilp8 Coordinates Drosophila Tissue Growth with Developmental Timing

Small But Perfectly Formed The imaginal discs of Drosophila represent defined larval tissues that give rise to the subsequent adult appendages. These tissues regenerate in response to damage. When the imaginal discs are injured or show tumor growth, they signal to the rest of the larval animal to slow down growth and delay morphogenesis. Garelli et al. (p. 579 ) and Colombani et al. (p. 582 ) now show that an insulin-like peptide, termed Dilp8, is secreted into the hemolymph (insect “blood”) and participates in the communication between growing organs and the endocrine system to adjust the growth program and maturation time. This collaboration ensures that adults attain the normal size and maintain appropriate proportions and symmetry.