Xyela obscura ( Strobl, 1895 )

Blank, Stephan M., Shinohara, Akihiko & Altenhofer, Ewald, 2013, <strong> The Eurasian species of <em> Xyela </ em> (Hymenoptera, Xyelidae): taxonomy, host plants and distribution </ strong>, Zootaxa 3629 (1), pp. 1-106 : 46-48

Xyela obscura ( Strobl, 1895)

Pinicola julii var. obscura Strobl, 1895: 277 , ♀, type locality: Austria, Styria, environs of Admont, Scheibleggerhochalpe ; Konow 1897: 58 (junior synonym of julii).

Xyela obscura: Benson 1960: 110 (removed from synonymy, combination with Xyela ).

Xyela julii var. tatrica Gregor in Gregor & Baťa, 1940: 225, ♀, type locality: Slovakia, Vysoké Tatry Mountains, Štrbské Pleso; Beneš 1975: 121 (junior synonym of obscura ).

Xyela curva: Benson 1961: 171 (misidentification).

Xyela julii: Rasnitsyn 1965: 515 (partly misidentified).

Description. Female. Color. Head dark brown to black, sometimes with indistinct brown stripes on vertex between kidney-shaped spot and eye margin ( Fig. 64 ). Antennae brown, ventrally a little paler. Thorax dorsally brown, seldom with indistinct brown pattern on mesonotal lobes, tegulae pale and largely brown in middle. Thorax ventrally brown, mesepisternum pale brown. Abdomen brown, tergum 8 and 9+10 laterally pale brown. Valvifer 2 yellow or pale brown, membrane between valvifer 2 and valvula 3 white, valvula 3 pale brown, preapically infuscate and pale at tip ( Fig. 113 ). Legs pale brown, coxae brown, femora more or less darkened. Wings almost clear, venation and pterostigma pale brown.

Morphology. Fore wing 3.6–4.3 mm long, 2.00–2.15 times longer than ovipositor sheath, vein Rs+M 230–330 µm long, 2r-m meeting Rs proximal to furcation of Rs1 and Rs2. Synantennomere 3 560–730 µm long, antennomere 4 130–180 µm long and 3.5–4.5(– 5.5) times longer than wide distally. Article 3 of maxillary palp 430–530 µm long, 1.50–1.75 times longer than scape and wider than synantennomere 3. OOL: POL = 1.60–2.10: 1. Ovipositor sheath 1.75–2.10 mm long, valvula 3 1.75–2.00 times longer than valvifer 2 and 6.5–7.5 times longer than wide at base ( Fig. 113 ). Valvula 3 of ovipositor compressed, pale membranous area about as long as basal width of valvula 3, dorsal edge of valvula 3 sloping down to round tip, distally with sensilla field exposed and directed caudally, bearing 3 setae. Ovipositor almost straight and compressed. Valvula 1 with aulax terminating distally, ventral edge sloping up to tip, with ca 14–15 oblique closely spaced annuli in distal quarter, without serrulae, olistether with 4–5 setae. Left and right valvulae 2 fused along dorsal edge in basal half. Valvula 2 with smooth dorsal margin, tapering in distal half, pale and evenly sclerotized, in distal 0.4 with single sensilla campaniformia, in distal 0.1 with 4–5 annuli. Posterior tibia 0.80–1.00 mm long, claws without subapical tooth.

Male. Color. Head yellow with black and brown pattern: frontal furrows usually with wide stripes meeting ocellar and postocellar spot, medial spot of frons present and sometimes fused with frontal stripes, kidney-shaped spots on vertex separate from black postocellar area and often fused with frontal stripes anteriorly ( Fig. 65 ). Antennae pale brown. Thorax dorsally black, pronotum, mesonotal lobes and mesoscutellum sometimes pale brown, tegulae pale and brown in middle, mesepisternum largely pale brown. Abdomen including hypopygium brown. Legs pale brown, posterior coxae laterally brown and ventrally brown in the basal and more or less pale in distal half. Wing membrane almost hyaline, venation and pterostigma pale brown.

Morphology. Fore wing 2.9–3.9 mm long, Rs+M 130–330 µm long, 2r-m meeting Rs proximal to furcation of Rs1 and Rs2. Synantennomere 3 (560–)630–740 µm long, antennomere 4 140–190 µm long and 4.5–6.0 times longer than wide distally. Article 3 of maxillary palp 400–470 µm long, 1.35–1.60 times longer than scape and wider than synantennomere 3. OOL: POL = (1.50–)1.75–1.90: 1. Longitudinal apodeme of basiparamere curved, basal portion in lateral position, harpe about as long as wide in lateral view. Lower ergot on valvular stalk absent. Valviceps 1.44–1.55(–1.60) times longer than wide on medial lobe, with distinct oblique lateral lamella, proximal lobe of penis valve 0.23–0.28 times as long as valviceps and 0.70–0.75 times as high as medial lobe, excision of lower edge 0.20–0.23 as deep as width of medial lobe, valviceps on medial lobe 1.10–1.20 times wider than on distal lobe, 2 distal flagella present, tip of longer flagellum reaching 0.60–0.70 width of distal lobe ( Fig. 146 ). Valviceps with median longitudinal sclerotization present, medial lobe almost symmetric and broad, with 5–9 cone-like sensilla along upper edge and scattered on lateral surface, upper edge between medial and distal lobe with 5–13 setae. Posterior tibia 0.80–1.00 mm long, claws without subapical tooth.

Type material. Pinicola julii var. obscura . Lectotype ♀ (designated by Schedl 1978): [label added by G. Morge, green handwriting:] “4”; “ Xyela obscura (Strobl) ♀ stat. nov. Benson 1960 det. W. Schedl 1971”; [red:] “ Lectotypus ♀ Pinicola julii var. obscura Strobl, 1895 S. M. Blank 1999 ”; [hereby added copy of cabinet label:] “ X. Julii v. obscura m. Scheibleggerhochalpe 26/5 94 ♀ ”; “ Xyela obscura (Str.) ♀ det. S. M. Blank 1999”. In perfect condition. NMBA. Paralectotypes: 1♀ with Strobl’s label “ v. obscur [sic!] Scheiblstein [...; illegible Gabelsberg stenography] 6/6 95 ♀. Strobl” and Morge’s label “5” and 1♀ with Strobl’s label “ Jul. v. obsc . Kalbling [...; illegible Gabelsberg stenography] 8/6 95. ♀.” and Morge’s label “6”, NMBA.

Xyela julii var. tatrica Gregor, 1940 . NMP, not studied.

Host plant. Pinus banksiana Lamb. ( Benson 1962) , Pinus cembra L. ( Schedl 1980), P. densiflora Sieb. & Zucc. ( Kondo & Miyake 1974, Miyake & Kondo 1974), P. elliottii Engelm. ( Smith 1978) , P. heldreichii Chr. ( Blank 2002) , ● Pinus mugo Turra (55♀ 58♂ from 3 reared samples), Pinus nigra Arn. ( Beneš 1975) , P. palustris Mill. ( Benson 1962) , P. ponderosa Laws. ( Benson 1962) , P. taeda L. ( Smith 1978), P. virginiana Mill. ( Benson 1962) , P. uncinata Ramond ( Blank 2002) .

Biology. In samples from Pinus mugo , larvae of the weevil Doydirhynchus austriacus (Olivier, 1807) (Cimberidae, Curculionoidea; det. L. Behne) were sometimes abundant, which are also internal feeders on the staminate cones. For additional data see Blank (2002).

Geographic distribution. Austria, Bulgaria, Germany, Italy, Slovakian Republic ( Roller et al. 2006), Switzerland ( Fig. 19 ). Additionally recorded from the Carpathian Basin ( Zombori 1974) and the Ukraine ( Zombori & Ermolenko 1999). The record for France ( Blank 2002) refers to X. uncinatae . Rasnitsyn’s (1965) record for the Altai Mountains is a misidentification of X. julii . Records from Japan and North America (e.g., Benson 1962, Togashi 1974) refer to other Xyela species.

Remarks. See Xyela julii and X. uncinatae for diagnosis. The sexes have been associated with the help of imagines reared from Pinus mugo .

Beneš (1975) studied the type material of X. julii var. tatrica in NMP and identified it as X. obscura . This material was unavailable to us, but we checked two females from HNHM labeled “Štrbské Pléso 21 Obenberger”, which most likely were collected at the type locality, and which agree well with the concept of X. obscura .

Benson (1961, 1962) considered X. obscura to be a Holarctic species, and he synonymized the East Palearctic X. japonica and the Nearctic X. pini Rohwer, 1913 with it. Actually X. obscura is restricted to Europe, and the other names actually concern X. japonica and species associated with the X. minor group.

The host records of P. banksiana , P. elliottii , P. palustris , P. ponderosa , P. taeda and P. virginiana for X. obscura resulted from Benson’s (1962) erroneous synonymy of the Nearctic X. pini with this species (see Burdick 1961 and Ebel 1966 for primary data). Kondo & Miyake (1974) and Miyake & Kondo (1974) reported P. densiflora for Japanese X. ‘ obscura ’, but actually they had studied a mixture of X. tecta and X. variegata . The record of P. cembra is due to repeated collecting of X. obscura imagines from this pine ( Benson 1960, 1961, Schedl 1978), which may occur syntopically with P. mugo in the subalpine zone. Beneš (1975) listed P. nigra doubtfully as an additional host plant. Actually X. obscura has never been reared from P. cembra and P. nigra . All these pines are to be excluded as host plants for X. obscura .

Figures

FIGURE 19. Records of three West Palearctic, subalpine Xyela species, X. helvetica (2 specimens from 2 collection sites), X. obscura (221 specimens from 30 collection sites) and X. uncinatae (48 specimens from 9 collection sites) and natural distribution of the (supposed) host plants, Pinus mugo (solid line) and P. uncinata (dashed line, distribution of both pines according to Meusel et al. 1965). The distribution ranges of these pine species overlap in the Alps (see text). Additional literature record included for X. obscura from the Ukraine (Zombori & Ermolenko 1999).

FIGURES 42–65. Color pattern of head of Xyela species: X. curva group, X. rasnitsyni group, X. julii group (part). Legend: HT—holotype; NT—neotype; PT—paratype.

FIGURES 105–120. Ovipositor sheaths of Xyela species. All figures at same scale. Legend: HT—holotype; NT—neotype; PT—paratype.

FIGURES 146–156. Penis valves of Xyela species (X. julii group, part), and male external copulatory apparatus of Xyela in ventral and lateral view. 153–154, X. longula (penis valves removed). 155–156, X. curva (penis valves and volsellae removed). Legend: bpa—basiparamere, br—basal ring, gon—gonomacula, har—harpe, lap—lateral apodeme, vol—volsella. Figs 147, 150 and 152 reproduced from Blank et al. (2005).