Probably required to stimulate the proliferation, polarization and motility of imaginal disk cells. May act by stabilizing the binding of insulin-like peptides to its receptor through a simultaneous interaction with both molecules to form a multiprotein signaling complex (By similarity). It is transported to target tissues via hemolymph. In larvae, it is expressed in the fat body and by hemocytes. Expressed throughout development and in adults. Glycosylated. Belongs to the glycosyl hydrolase 18 family. IDGF subfamily. Lacks the typical Glu active site in position 165 that is replaced by a Gln residue, exhibits no chitinolytic activity towards either polymeric and oligomeric substrates. Its precise function remains unclear.