Apolygus limbatus (Fallén, 1807)

Figures 5 C – E, 7 E – H, 9 R – U, 11 A – D, 15 G, 15 H, 18 E, 18 F, 18 I, 18 J, 19 S – V

Lygaeus limbatus Fallén 1807: 85 (original description).

Lygocoris (Apolygus) limbatus Carvalho 1959: 137 (catalogue); Kerzhner and Jaczewski 1964: 720 (key to species, figures of male genitalia); Wagner and Weber 1964: 201 (key to species, figures of male genitalia); Miyamoto et al. 1994: 11 (species list); Vinokurov and Kanyukova 1995: 90 (key to species, figures of male genitalia); Schuh 1995: 798 (catalogue).

Lygocoris limbatus Kulik 1965 a: 46 (species list); Kulik 1974: 12 (species list).

Lygus (Apolygus) limbatus Wagner 1974: 401 (key to species, figures of male genitalia); Kerzhner 1988 b: 805 (key to species).

Apolygus limbatus Kerzhner and Josifov 1999: 65 (catalogue); Seong and Lee 2007: 326 (key to species); Vinokurov et al. 2010 (list of species); Kim and Jung 2016: 597 (key to species); Oh et al. 2018: 10 (species list, key to species); Vinokurov et al. 2024: 247 (catalogue).

For the full list of references see Carvalho (1959), Schuh (1995), Kerzhner and Josifov (1999), Vinokurov et al. (2010), Vinokurov et al. (2024).

Material examined.

Other material. Belarus, Finland, Kazakhstan, Lithuania, Mongolia, Poland, Serbia, Russia, Altai Terr., Amur Prov., Arkhangelsk Prov., Bryansk Prov., Irkutsk Prov., Jewish Prov., Khabarovsk Terr., Khanty-Mansi Distr., Leningrad Prov., Magadan Prov., Primorsky Terr., Pskov Prov., Ryazan Prov., Samara Prov., Tula Prov., Yaroslavl Prov., Zabaikalsky Terr. • many ♂♂, ♀♀ (See File S 1).

Diagnosis.

Length in male 4.8–5.4 mm (European form), 5.1–5.5 mm (Asian form), in female 4.7–5.2 mm (European form), 4.9–5.5 mm (Asian form). Head yellow, clypeus entirely or mostly pale brown to dark brown (Fig. 15 G, H); antennal segment I yellow; antennal segment II yellow with pale brown to brown apical half or less, sometimes basal 1 / 3 also pale brown to brown; pronotum yellow sometimes pale brown or brown basally and often with brown to dark brown markings around calli, sometimes mostly brown to dark brown; scutellum varying from uniformly yellow to mostly brown to dark brown with yellow apex; clavus pale brown to dark brown, corium yellow, with brown to dark brown marking posteriorly, usually not reaching embolium, rarely reaching embolium only posteriorly; lateral margin of embolium brown to dark brown; cuneus yellow, brown to dark brown basally, pale apically (Fig. 11 A – D); pleura including metathoracic scent gland evaporative area yellow; legs mostly yellow, at least hind femur with red or brown rings apically, sometimes most part of hind femur with red tinge; tibia yellow with dark brown to black markings at bases of spines and dark brown or red brown marking basally. — Male genitalia. Apical process of right paramere subequal to paramere body (Fig. 19 S – V); sublateral sclerite present, toothed, acute apically; needle-shaped sclerite surpassing secondary gonopore and apex of wing-shaped sclerite, but not reaching apex of ventral sclerite; wing-shaped sclerite with straight outer margin, as wide as lateral sclerite and wider than median sclerite. European form: wing-shaped sclerite ca. 4–5 × as long as wide, needle-shaped sclerite subequal to wing-shaped sclerite (Fig. 18 E, F). Asian form: wing-shaped sclerite ca. 2–3 × as long as wide, distance between wing-shaped sclerite and needle-shaped sclerite apices 0.2–0.3 × as long as needle-shaped sclerite (Fig. 18, J).

Distribution.

Apolygus limbatus can be considered as trans-Palearctic, but it does not live in the southern parts of Russia (Vinokurov et al. 2024). This species is known from the Russian Far East, i. e. Amur, Khabarovsk, Primorsky Territories (Kerzhner 1988 b; Vinokurov et al. 2010) and East Asia, i. e. Korea (Kim and Jung 2016; Oh et al. 2018).

Host plants.

Apolygus limbatus lives on Salix spp. (Kerzhner and Jaczewski 1964; Kulik 1965 a; Kerzhner 1988 b; ZIN), it was also recorded from Populus sp. (Kulik 1965 b, 1974; Wagner 1974).

Notes.

According to Kerzhner and Josifov (1999), Apolygus limbatus is known from Japan, but it is absent in the species list for Japan (Yasunaga 2023).

We found that the specimens identified as A. limbatus have two types of sclerotization in vesica and this corresponds to the distribution: Europe (reaching Ural Mountains) and Asia (Fig. 18 E, F, I, J). The drawing of vesica in the key to the Heteroptera of the European part of the USSR (Kerzhner and Jaczewski 1964) corresponds to the European form. Those groups can represent two separate species; however, we did not find any differences in the shape of the parameres and habitus between them, and the molecular data were insufficient to resolve this problem. More specimens from those groups and nuclear markers should be included in the analysis. Therefore, we refrain from any taxonomic decisions pending additional molecular data. Apolygus limbatus is most similar to A. maackiae in coloration, but the latter differs in the apex of cuneus dark brown to black, yellow outer margin of embolium and yellow legs without reddish tinge. Additionally, in A. maackiae wing-shaped sclerite is absent and its ventral sclerite has needle-shaped outgrowth (Fig. 18 G, H).