The present invention provides Drosophila melanogaster GPCR (DmGPCR) polypeptides and polynucleotides which identify and encode such a DmGPCR. In addition, the invention provides expression vectors, host cells, and methods for its production. The invention also provides methods for the identification of homologs in other species and of DmGPCR agonists/antagonists useful as potential insecticides. The invention further provides methods for binding a DmGPCR, methods for identifying modulators of DmGPCR expression and activity, methods for controlling a population of insects with a DmGPCR antibody, a DmGPCR antisense polynucleotide, a DmGPCR binding partner or modulator, and methods of preventing or treating a disease or condition associated with an ectoparasite. Specifically, this invention discloses the matching of the orphan Drosophila drotachykinin, droleucokinin, and drostatin-C receptors with their cognate peptide ligands.