Phylogenetic tree of HzDHr and its related G protein-coupled receptors. A total fifteen sequences were included in this analysis, in which the Drosophila myosuppressin receptor 2 (MSr2) served as the outgroup. The tree was inferred in MEGA 5 applying the Neighbor-Joining method with 1,000 bootstrap tests. The percentage of 1000 bootstrap replicates supporting each node is indicated. Species abbreviations: Msex, Manduca sexta, Msep, Mythimna separate; Dple, Danaus plexippus; Bmor, Bombyx mori; Onub, Ostrinia nubilalis; Othy, Orgyia thyellina; Hzea, Helicoverpa zea; Harm, Helicoverpa armigera; Hvir, Heliothis virescens; Sexi, Spodoptera exigua; Slit, Spodoptera littoralis; Pxyl, Plutella xylostella.