MOLECULAR ENTOMOLOGY DNA-Based Identification of Spider Mites: Molecular Evidence for Cryptic Species of the Genus Tetranychus (Acari: Tetranychidae)

ABSTRACT Spider mites are difÞcult to identify because they are very small and have a limited number of diagnostic characters. Most species of the spider mite genus Tetranychus in Japan are morphologically similar, differing only in the diameter of the aedeagal knob in males. Because this genus containsmany important pests, the unambiguous identiÞcation of species is crucial for effective pest management and quarantine procedures. DNA-based methods could complement the morpho-logical methods. We examined whether Tetranychus species in Japan could be identiÞed by DNA sequences using the internal transcribed spacer region of nuclear ribosomalDNAand the cytochrome c oxidase subunit I gene of mitochondrial DNA. We determined sequences of the 13 known Tet-ranychus species in Japan. We could identify 10 of the 13 species in the internal transcribed spacer tree. In the cytochrome c oxidase subunit I tree, we could identify all 13 known Tetranychus species in Japan. Although Tetranychus kanzawaiKishida and T. parakanzawai Ehara were identiÞed by DNA sequences, they were clearly separated into two monophyletic clades each, indicating that a cryptic species existed in each species. KEY WORDS DNA-based identiÞcation, Tetranychus, internal transcribed spacer, cytochrome c oxidase subunit I, cryptic specie