Proof on the Divergence Times of Two Sympatric Species, Rhynchophorus ferrugineus and R. vulneratus (Coleoptera: Curculionidae) by Molecular Clock Analysis

Özet

Molecular clock analysis on the oil palm weevil has separated the Red Palm Weevil, Rhynchophorus ferrugineus and Asiatic palm weevil, Rhynchophorus vulneratus as two sympatric species. Calibration was performed using the fossil of R. cruentatus which had evolved approximately 1 mya using sequences data of combined COI and Cytb. Divergence time indicated that R. cruentatus, the outgroup species evolved around 80.598±10 mya and finally speciated to form R. ferrugineus (≈1.926±10 mya) and R. vulneratus (≈4.857±10 mya). Additionally, the construction of Neighbour Joining (NJ) and Maximum Parsimony (MP) trees showed distinct separation using COI, Cytb and combination of COI and Cytb. These findings were highly supported by genetic distance analysis. Although a limited number of individuals from the small geographical area was used in this study, the genetic molecular clock analysis of mitochondrial data was able to effectively differentiate both species. These results reveal the first analysis to use the molecular clock to confirm the separation of these two sympatric species.