First Discovery of the North American Leaf-Mining Moth Chrysaster ostensackenella (Lepidoptera: Gracillariidae) in Russia: The Genetic Diversity of a Novel Pest in Invaded vs. Native Range

Simple Summary The leaf-mining moth Chrysaster ostensackenella (Fitch, 1859) (Lepidoptera: Gracillariidae) is the North American species that damages the leaves of Robinia spp. (Fabaceae). Recently, it was detected on the introduced North American black locust Robinia pseudoacacia (Fabaceae) in East Asia (China, South Korea, Japan) and Europe (Italy). In July 2022, Ch. ostensackenella was for the first time found on the territory of Russia, in Primorsky Krai. We studied the bionomics of this invasive moth and highlighted the characteristics of leaf damage by which the presence of Ch. ostensackenella can be detected early. Furthermore, we DNA barcoded three moth specimens from Primorsky Krai and analyzed them against DNA barcodes of Ch. ostensackenella from invaded countries in Europe (Italy) and East Asia (South Korea and Japan) and the native range (North America). Overall, our findings suggest that Ch. ostensackenella distributed to East Asia from the USA directly, not through Europe, whereas to the Russian Far East, this invasive moth spread from early invaded East Asian countries, in particularly Japan. Here, we report the first detection of the North American leaf-mining moth Chrysaster ostensackenella (Fitch, 1859) (Lepidoptera: Gracillariidae) on North American black locust Robinia pseudoacacia (Fabaceae) in Primorsky Krai (the Russian Far East) in July 2022. Overall, six moths were reared from the leaf mines and identified based on adult morphology (forewing pattern and male genitalia) and three of them were DNA barcoding. Description of the leaf mines that allowed us to distinguish the damage of Ch. ostensackenella from other gracillariids associated with R. pseudoacacia is provided. The phylogeographic analysis comparing the DNA barcodes from Russia with those from other invaded countries in Europe (Italy) and East Asia (South Korea and Japan) and from the native range (North America) was performed. Intraspecific genetic diversity reached 3.29%. Altogether, 10 haplotypes were revealed among 21 studied specimens in the Holarctic. The detection of one haplotype common for Japan and the USA (North Carolina) suggests that the invasion to East Asia could have happened from the USA directly, rather than through Europe. A shared haplotype defined for Japan and the Russian Far East points at a possible moth species' spread to Primorsky Krai from earlier invaded Hokkaido. Further distribution of Ch. ostensackenella in East Asia and Europe is expected, bearing in mind the wide planting of R. pseudoacacia in these continents. Furthermore, an accidental introduction of the moth to the Southern Hemisphere, where black locust was introduced, is not ruled out.