Salicaceae-Feeding Leaf-Mining Insects in Siberia: Distribution, Trophic Specialization, and Pest Status

This paper provides an overview of the leaf-mining insect community feeding on willows (Salix spp.) and poplars (Populus spp.) in Siberia. According to published data and our own observations, 50 leaf-mining insect species (i.e., 24 species of Lepidoptera, 15 Coleoptera, 6 Diptera, and 5 Hymenoptera) feed on those two plant genera in Siberia. Using an integrative approach combining field work, morphological and DNA barcoding analyses, we identified 32 leaf-mining insect species from 14 regions across Siberia (i.e. 64% of all leaf-mining species known on Salicaceae in this part of Russia). Among them, 26 species most often found in parks and botanical gardens, represented new faunistic records for several poorly explored regions of Siberia. We have more than doubled the list of Salicaceae-feeding leaf-mining insects in Tomsk oblast, Altai krai, and the Republic of Tuva, and for the first time provided data on leaf-miners for the Khanty–Mansi Autonomous Okrug. The micromoth Phyllocnistis gracilistylella (Gracillariidae), recently described from Japan, was found on a new host plant (Salix caprea) in the south of Krasnoyarsk krai, is new for Russia. Eight leafmining insect species (i.e., five gracillariids: Phyllocnistis labyrinthella, Ph. unipunctella, Phyllonorycter apparella, Ph. sagitella, and Ph. populifoliella; two beetles: Zeugophora scutellaris and Isochnus sequensi; and one sawfly: Heterarthrus ochropoda) can outbreak on poplars, most often in urban plantations, botanical gardens, and plant nurseries in Siberia, and can also affect natural stands. Forty-five species of 50 leaf-mining insects known to feed on willow and poplar in Siberia also occur in Central and Eastern Europe. The remaining five species (Phyllocnistis gracilistylella, Phyllonorycter sibirica, Heterarthrus fasciatus, Tachyerges dauricus, and Isochnus arcticus) are recorded in Asia only. Species richness of the family Gracillariidae, the most diverse on Salicaceae in Siberia, displays 80% similarity to that in the European part of Russia and 71% to the Russian Far East. We discuss the faunal similarity of these regions and highlight the importance of applying an integrative approach combining ecological, morphological analyses, and DNA barcoding to explore and characterize the insect fauna of poorly studied regions of Asian part of Russia.