Acasis exviretata Inoue 1982

Acasis exviretata Inoue

(Figs 24, 59a, 59b, 60)

Acasis exviretata: Beljaev & Mironov 2019: 256, 386 (note 8679) (Sakhalin).

? Acasis appensata baicalensis (sic.!) [baikalensis], nec (Bang-Haas): Viidalepp 1978: 758 (Sakhalin); Viidalepp 1996: 48 (Sakhalin); Kurina 2022b: GBIF occurrences 3023176725, 3023179773, 3023181731 (Pyatirechye).

Material examined. 2 ♂, S Kholmsk, 03.VII.2017, 20.VI.2021; 4 ♂, 7 ♀,Yasnomorskoe, 19, 20, 23, 25, 26.VII.2019; 1 ♂, Yasnomorskoe, 18, 19.VIII.2020; 1 ♂, “Kaibato [Moneron], 6.VIII [19]34, Saghalien Cent. Exp. Sta. ”.

Distribution. Russia (S RFE: SW Sakhalin, *Moneron, S Kurils—Kunashir), Japan (Hokkaido, Honshu).

Remarks. The finding of A. exviretata in Sakhalin significantly expands its distribution range to the north. The host plants of the larvae of this species in Japan are Actaea simplex and A. japonica (Ranunculaceae) (Hashimoto 2021). In Sakhalin the moths were recorded from mid-June to second half of August; possibly, the species develops here in two generations.

Presence of true A. appensata in Sakhalin is doubtful (Table 2). The report of “ Acasis appensata baicalensis ” (Viidalepp 1978, 1996; Kurina 2022b) from “Pjatiretšje” (a Pyatirechye village in the Kholmskii urban district, SW Sakhalin) is probably based on a misidentification of A. exviretata, since this place is located close to our colection sites of the latter species.

Beljaev & Mironov (2019), along with the first report of this species from Sakhalin, restored A. exviretata from a synonymy with A. appensata (Eversmann) but without the material data and argumentation. Recently Hashimoto (2021) also accepted specific status of A. exviretata and provided its discriminating characters compared to A. appensata (loc. cit.: 54). Nevertheless, he also admitted a possible subspecific status of A. exviretata relatively to A. appensata. However, these two taxa clearly differ in a number of stable characters and do not have the “transitional” features between the neighbouring island and continental populations. Thus, morphologically, specific status of A. exviretata is not doubtful. Indication of Korea in the distribution of A. exviretata by Hashimoto (2021) was taken from Choi (2007b). But the photos of the moths and the genitalia of “ Acasis appensata ” (Choi 2007b, figs 3, 4, 8, 9, 13), which actually correspond to A. exviretata, apparently were taken from the Japanese specimens, since those from Korea are not mentioned by Choi in the examined material. The report of A. exviretata from Korea by Oh (1994) is based on a misidentification of A. appensata, as it is seen from the photos of the moth and the male genitalia (Oh 1994, figs 2 and 6). So, the reliable data on A. exviretata in Korea are absent.