Gracillaria sp.

(Fig. 11A)

Material examined. Russia: PK, Gornotaezhnoe, MTS, 43.69N, 132.15E, 152 m alt., Syringa amurensis, 22.VII.2016, 1 larva, NK549 , MK 403699, (INRA); same location, Fraxinus mandshurica, 25.VII.2016, 1 larva, NK547 , MK 403728, deposited in INRA.

Leaf mine. The mine is a big silvery blotch, slightly branched, on the upper side of the leaf often at some distance from the leaf margin (Fig. 11A). It begins as a short distinctive epidermal tunnel which soon widens into a blotch. In the tunnel, frass froms an orange-brown central line; in the blotch part, the frass line is darker and more pronounced, covering the mine epidermis from beneath. Later, silk is deposited within the blotch mine which contracts slightly (Fig. 11A). The mine somewhat reminds of the one of Callisto . Pupation site unknown.

Trophic specialization. Oligophagous on Oleaceae: Fraxinus mandshurica, Syringa reticulata subsp. amurensis .

Distribution. Russia: RFE—PK.

Remarks. BIN of unknown species—BOLD: ADF4930. The two larvae of Gracillaria sp. showed no divergence in COI barcoding fragment and were assigned to one BIN in BOLD (Table 1). Overall, in the Palearctic, seven Gracillaria species are known to develop on Oleaceae (De Prins & De Prins 2018) . Among them four species have distribution in East Asia: Gracillaria albicapitata Issiki (hosts: Fraxinus, Syringa), G. arsenievi (Ermolaev) ( Fraxinus, Syringa), G. japonica Kumata (Ligustrum) and G. ussuriella (Ermolaev) (Fraxinus) . Others are known from Europe: G. loriolella Frey (Fraxinus), G. syringella (Fabricius) ( Fraxinus, Syringa) and one from North Africa G. toubkalella De Prins (Fraxinus) . The minimum genetic divergence of Gracillaria sp. from other Gracillaria species known to feed on Oleaceae varied from 6.5 to 9.8%. Among them, the closest neighbor to Gracillaria sp. is G. loriolella (6.5%), followed by G. cf. japonica (6.8%), G. syringella (8.0%) and G. ussuriella (9.8%) (Table 2). A DNA barcode of G. albicapitata is present in BOLD but not accessible; nevertheless, this species does not appear in the list of top matches with our specimens. BIN BOLD:ADF4930 to which both Gracillaria sp. from RFE and Gracillaria sp. RN-2016 from Japan (deposited in BOLD) may belong to G. arsenievi (Ermolaev) whose larvae develop on Fraxinus and Syringa . However, G. arsenievi barcodes are unavailable in genetic databases and we could not examine any adult moth of Gracillaria sp. in the present study.