Abstract
Palm weevils (Coleoptera: Curculionidae) are the most destructive pest of many palm species worldwide, including Indonesia. Accurate species identification and knowledge of their diversity is crucial for implementing management strategies. Some samples of palm weevils from six main islands of Indonesia were found exhibiting intermediate color and markings between those of Asiatic palm weevil (APW), Rhynchophorus vulneratus Panzer and red palm weevil (RPW), R. ferrugineus (Olivier). To test the hypothesis that intermediate occurring phenotypes in Indonesia are only phenotypic color variations of APW, morphometric analyses, mating trials, and the analysis of cytochrome b (CyB) and random amplified polymorphism DNA (RAPD-PCR) were carried out. Additionally, RPW from the Kingdom of Saudi Arabia (KSA) and Pakistan were compared to Indonesian samples. Morphology-based identification of Indonesian palm weevils recognized three putative taxa: R. ferrugineus, R. vulneratus, and the black palm weevil, R. bilineatus (Montrouzier). It was suspected that intermediate color phenotypes of APW from Indonesia had been ambiguously considered RPW. Discriminant function analysis of morphometric measurements indicated that an intermediate weevil, which was previously determined to be RPW, are highly similar to APW. The mating trials of intermediate weevils and APW produced fertile progenies for three successive generations. The CyB and RAPD-PCR analyses showed that the intermediate phenotypes previously identified as RPW are distinguishable from RPW from the KSA. Therefore, our findings indicate that these are color phenotypes of APW. Thus, based on the palm weevil samples in this study, only two species exist, namely, R. vulneratus and R. bilineatus.