Drosophila adipokinetic hormone (DAKH) is an eight amino acid member of a large arthropod neuropeptide family. The gene encoding the peptide precursor has been identified and sequenced providing an inferred precursor structure of 79 amino acids including a 46 amino acid carboxy-terminal fragment of unknown function. In situ hybridization identifies sites of DAKH synthesis towards the base of the third larval instar ring gland. Like other RPCH (red pigment concentrating hormone)/AKH family peptides, DAKH can act as a cardioaccelerator at least in prepupae. Peptide levels measured in wildtype and mutant flies possessing one or three copies of the DAKH gene suggest that the amount of neuropeptide per fly is tightly regulated.