Eurytoma arctica, THOMSON, 1876

Delvare, Gérard, Gebiola, Marco, Zeiri, Asma & Garonna, A. P., 2014, Revision and phylogeny of the European species of the Eurytoma morio species group (Hymenoptera: Eurytomidae), parasitoids of bark and wood boring beetles, Zoological Journal of the Linnean Society 171 (2), pp. 370-421 : 388-390

EURYTOMA ARCTICA THOMSON, 1876 ( FIG. 13A–K )

Eurytoma arctica Thomson, 1876: 48 . Original description. Sweden. Boucˇek & Graham, 1978: 225: Distribution UK.

Eurytoma blastophagi Hedqvist, 1963: 38–41 . Original description. Sweden.

Host: Tomicus (= Blastophagus ) minor (Hartig, 1834) . Zerova, 1995: 160–161 and 366; Zerova, 2010: 62, 137.

= Eurytoma blastophagi Hedqvist : Boucˇek & Graham, 1978: 225.

Type material

Eurytoma arctica . Lectotype ♀, designated by Graham (in MZLU). For the labelling, see Figure 9A . Eurytoma blastophagi . Holotype ♀ (previously in Hedqvist’s personal collection, now in BMNH). For the labelling, see Figure 9C .

Remarks

The species was redescribed by Hedqvist (1963) under E. blastophagi , the type of which belongs to the same species as E. arctica . Zerova (1995, 2010), ignoring the synonymy proposed by Boucˇek & Graham (1978), still used the name E. blastophagi . Her concept of E. arctica is actually the same as E. maura .

Diagnosis

Female. Head relatively transverse in dorsal view, 1.85– 1.90 times as wide as long. Outline of genae straight or almost so. Clypeus protruding ventrally and slightly emarginate on ventral margin. Lower face punctured with short radiating crests and smooth subantennal stripe. Setation relatively thick and dense on mesal part of face. Eye height 1.20 times width of malar space. Vertex entirely punctured. Lateral ocellus diameter smaller than OOL (86: 97). Temples 0.25– 0.30 times length of eye, and merging with occiput. Scape at least with reddish–testaceous base, sometimes entirely so. All funicular segments longer than wide. Pronotal collar densely punctured. Notauli narrow and appearing as impressed lines, not or partly obliterated by the sculpture of the mesoscutum. Anterior outline of mesepisternum hardly convex. Procoxa black. Metacoxa bare dorsally at base. Costal cell with a large bare stripe on lower surface, the setation not especially dense. Marginal vein not thickened, at least 6.0 times as long as wide. Gaster elongate and distinctly compressed laterally, 2.20 times as long as height of third gastral tergite. Ovipositor moderately ascending.

Male with scape black with pale base. Scape quite prominent ventrally. F5 symmetric and with very short apical peduncle, the other segments elongate and only fairly nodiform. Propodeum with median channel hardly impressed.

Hosts

The hosts of some syntypes of E. auricoma (actually belonging to E. arctica , see below) are Tomicus (= Hylurgus ) minor (Hartig, 1834) and Ips (= Tomicus ) sexdentatus (Borner, 1776) on Pinus nigra J.F. Arnold, 1785 . Pityogenes chalcographus (Linnaeus, 1761) , Dryocoetes autographus (Ratzeburg, 1837) , Pissodes harcyniae (Herbst, 1795) ( Titova, 1966) , and again T. minor were recorded as hosts ( Hedqvist, 1963; Titova, 1966). It therefore seems that the species parasitizes only hosts infesting coniferous trees; the records from deciduous trees are certainly erroneous and probably concern E. maura , which was misidentified as E. arctica by some authors, including Hedqvist (1963). We collected E. arctica on dead Pinus sylvestris L., 1753 and Larix decidua Mill. 1768 trees.

Distribution

The records from the UK (Boucˇek & Graham, 1978), Sweden ( Hedqvist, 1963), and Russia ( Titova, 1966) are certainly valid. We can also add Austria for some syntypes of E. auricoma . Others need to be checked with the relevant specimens. We collected species up to 1800 m a.s.l. in Haute-Maurienne (Savoie) and 1260 m a.s.l. in Cévennes (Ardèche) (see Appendices 4 and 8).

Figures

Figure 9. A–I, labelling of some types. A, lectotype ♀ of Eurytoma arctica Thomson, 1875; B, lectotype ♀ of Eurytoma umbilicata Thomson, 1876; C, holotype ♀ of Eurytoma blastophagi Hedqvist, 1963; D, holotype ♀ of Eurytoma fraxinicola Hedqvist, 1963; E, paratype ♀ of Eurytoma annilai Hedqvist, 1974; F, holotype ♀ of Eurytoma kangasi Hedqvist, 1966; G, paratype ♀ of Eurytoma kangasi Hedqvist, 1966; H, allotype ♂ of Eurytoma kangasi Hedqvist, 1966; I, holotype ♀ of Eurytoma kemalpasensis Narendran, Tezcan & Civelek, 1995.

Figure 13. A–K, Eurytoma arctica: A–H, female; I–K, male. A, head in frontal view; B, head in dorsal view; C, antenna; D, mesosoma in dorsal view; E, mesopleuron; F, propodeum; G, forewing; H, gaster in lateral view; I, antenna; J, scape; K, propodeum.