Abstract
Red palm weevil (Rhynchophorus ferrugineus Olivier) populations were collected from several regions in Saudi Arabia. Insects were graded based on different patterns of pronotum markings. The entire ITS1-5.8S-ITS2 region was cloned and sequenced for both R. ferrugineus and its related species R. vulneratus (Panzer). The novel ITS1 sequence form Rhynchophorus was found to be unique in the current Genbank database. Discrimination power of ITS1 region was shown to be much higher than ITS2 region. Penetrance of different pronotum markings varied from one region to another. The pronotum-based clustering diverged from that revealed by ribosomal sequence. Several Indels and nucleotide substitutions were detected along the ITS1-5.8S-ITS2 region between R. ferrugineus and R. vulneratus. The data support a two-species classification rather than considering them colour morphs of the same species.