First record of the cedar bark aphid, Cinara cedri cedri Mimeur, 1936 (Hemiptera: Aphidoidea) in Japan, and identification of infecting Wolbachia strains

Aphids are phloem sap-feeding insects distributed worldwide that can cause serious crop production losses, especially in temperate regions. Biological invasion by aphids is common, and the accumulation of case reports is important for their control. Here, we provide the first report of the cedar bark aphid Cinara cedri cedri (Hemiptera: Aphidoidea) in Japan. In Okazaki City, Aichi Prefecture, and Nishinomiya City, Hyogo Prefecture, we found this species on twigs of ornamental trees, Cedrus deodara. These two collection localities are clearly distant from the region of known distribution of this species. Cinara cedri cedri is native to the East Mediterranean region and has been introduced into several European countries, the USA, Canada, and Korea. The mitochondrial COI sequences of the Japanese populations matched the identity of those in the USA and Canada, recently introduced populations, and some European populations. Wolbachia is an endosymbiont of this species, and we found that those infected in the Japanese population of C. cedri showed no variation in 16S rDNA sequences. The sequences were identical to those of one of the two Wolbachia strains detected in the native ranges of C. cedri. We observed C. cedri populations from early summer to late winter in 2021 and early summer in 2022 in both localities, indicating that these aphids are able to overwinter in Japan.

Automated summary

This study reports the first discovery of the cedar bark aphid in Japan, which is native to the East Mediterranean region and has been introduced to multiple countries. The researchers found that the Japanese populations of this aphid species have the same mitochondrial COI sequences as populations in the USA, Canada, and some European countries, and they also carry the same strain of Wolbachia. Additionally, it was observed that these aphids are capable of overwintering in Japan.