Palm weevils (Curculionidae: Coleoptera) diversity in Indonesia: A morphometric approach based on pronotal typologies

Palm weevils are considered to be the highly damaging pests of various palm species worldwide. To clarify the plam weevils’ diversity in Indonesia, a total of 207 specimens were collected from 23 localities representing six main islands. The weevils were mostly collected from coconut palm, toddy palm and sago palm trees. Forty nine morphometric parameters including diversity of spots on pronotum were used. Also, the pattern of spots diversity on pronotum was described. Ultimately, one way analysis of variance (anova), based on morphometric parameters, was used to distinguish different color morphs and to clarify the species diversity. Our morphometric analysis has clearly separated different color morphs into three distinct groups; orange with black markings (Rhynchophorus ferrugineus, the red palm weevil), black with red stripes (Rhynchophorus vulneratus, the red stripe palm weevil) and black form (Rhynchophorus bilineatus, the black palm weevil).  However, it was suggested that ferruginous and vulneratus belong to the same species. Our inbreeding data upto three generations of these two morphs also conclude that they belong to the same species. Therefore, at least two distinct species representing three color morphs; the red palm weevil (RPW) (Rhynchophorus ferrugineus) or red stripe palm weevil (RSPW) (Rhynchophorus vulneratus), and black palm weevil (BPW) (Rhynchophorus bilineatus) exist in Indonesia. Further comparative studies both at morphometric and molecular levels for RPW and RSPW morphs with clear conformity of red palm weevil species from other country is suggested.