Canonical Discriminant Function biplot showing shifts in cuticular hydrocarbon profiles of female D. mojavensis from the four populations in this study exposed to zero humidity. 0, 9, and 18 hr mean centroids for CV 1 and 2 are shown, and P values refer to significantly different Euclidean distances between means. Cactus differences were not included. OPNM = Organ Pipe National Monument, Arizona; PO = Punta Onah, Sonora; PP = Punta Prieta, Baja California; SQ = San Quintin, Baja California.