Insect parasitic nematodes, Contortylenchus sp. (Tylenchida: Allantonematidae) from the spruce bark beetle Ips typographus and the large larch bark beetle I. cembrae (Coleoptera: Scolytidae) in Japan

Parasitic nematodes were found in the two bark beetle species Ips typographus and I. cembrae in Japan. Based on their ecological and morphological characteristics, these nematodes are identified as members of the genus Contortylenchus . They show some differences in not only parasitic manners but also molecular profiles. Ribosomal DNA sequences for small subunit (SSU), and D 2 -D 3 expansion segments of the large subunit (D 2 -D 3 LSU) of the nematodes in the two different beetle species are almost identical, but they show one base-pair substitution in the D 2 -D 3 LSU. These results suggest that the nematodes from I. typographus and I. cembrae are closely related but separate species. Interestingly, the D 2 -D 3 LSU of the nematode in I. typographus was identical to those of both Contortylenchus sp. from the Moscow region, the Russian Federation, and C. diplogaster in I. cembrae from the Czech Republic. This result indicates that the nematode in I. typographus is closely related to or could be conspecific to the European Contortylenchus species, including especially C. diplogaster or a related species, C. pseudodiplogaster . Nematol. Res. 49 ( 2 ), 45 – 47 . ( 2019 )