Oxyrrhexis carbonator (Gravenhorst, 1807)

El-Hennawy, Hisham K., 2017, First record of the genus Oxyrrhexis Foerster, 1869 (Hymenoptera: Ichneumonidae: Pimplinae, Ephialtini) for the fauna of Egypt, with an unexpected new host record, Zootaxa 4318 (1), pp. 187-194 : 189-193

Oxyrrhexis carbonator (Gravenhorst, 1807)

( Figs 7 , 9 ¯12a, b)

Polysphincta velata Hartig, 1838: 262 .

P. pusilla Fonscolombe, 1854: 516 .

Acrodactyla carbonatrix Schulz, 1906: 103 . Polysphincta carbonator ab. morio Hellén, 1915: 45. P. carbonator var. morio Kiss, 1929: 125 .

Material examined: Egypt: 2♀, 1♂, reared from three titanoecid spiders Nurscia albomaculata collected from Badr district , EL-Beheira Governorate (30°36'45"N, 30°37'34"E, elevation 22 m), Banana orchard, 5.iv.2014, leg. Ibrahim Zaher ( EFC). The adult wasps emerged from cocoons on 21¯ 22.iv.2014; Finland: 1♀, 1♂ received from Niclas R. Fritzén (Zoological Museum, University of Turku, Finland).

Diagnosis. Body colour greatly varied among the specimens examined, the most obvious of which is the presence of ivory marking at basal part of hind tibia; occipital carina complete; antenna of female with 18¯24 flagellomeres, sometimes reaching 27 ( Fritzén & Fjellberg 2014) while the males have 19-22 flagellomeres; lateral area of pronotum medially and anterior to the epomia smooth and shiny; female fore wing length 3.7¯ 6.4 mm., male 2.7¯4.0 mm; marginal cell of forewing short to relatively long, wing with radius short, nearly straight not reaching wing apex to long, ventrally concave reaching wing apex; hind coxa stout and reddish brown to black with yellow apex; size variable, from very small to medium-sized (5.2¯ 7.9 mm in female and 3.3¯ 5.5 mm in male); propodeum nearly smooth; the distal abscissa of hind wing joining cu-a is either equidistant between vein M and 1A or sometimes closer to 1A than to M.

Description. FEMALE. Body length 5.2‒6.8 mm. long; length of fore wing 3.7‒4.0 mm.

Head. Malar space 0.7 × basal mandibular width, without subocular sulcus; mandible slightly twisted, narrowing towards apex, with two subequal flattened, blunt teeth, upper tooth slightly longer than lower one, base of mandible densely hairy. Clypeus distinctly separated from face by moderately depressed supraclypeal suture. Face quadrate to subquadrate, about as high as broad, slightly convex in profile, with some dispersed fine and short setae and sparsely punctulate. Surface of eye with sparse, short whitish setae especially laterally. Antenna with 18¯20 flagellomeres; F1 5.0 × as long as broad, F2 4.0 × as long as broad. Maxillary palp 4-segmented; labial palp 3-segmented. Ocelli placed in an elevated equilateral ocellar triangle, lateral ocellus separated from eye by more than its own diameter (1.5 ×). Occipital carina sharp, complete, not interrupted medio-dorsally. Posterior margin of eye densely clothed with short, pale setae (when seen from dorsal aspect).

Mesosoma. Pronotum laterally with short, stiff setae, smooth and shiny. Mesoscutum densely, shallowly punctate, and clothed with fine pale pubescence, especially antero-laterally; notauli distinct along its upper third, not reaching posterior margin. Mesopleuron anteriorly, dorsally and laterally with fine pale pubescence, otherwise smooth and shiny and depressed in the middle; epicnemial carina extending dorsally beyond ventral corner of pronotum, with its posterior side in the form of irregularly elongated pits. Metapleuron more or less flattened, densely clothed with suberect silvery pubescence, submetapleural carina sharp and complete. Propodeum with two latero-median carinae, area in between smooth and shiny, glabrous, lateral areas with fine, relatively long setae Legs with front tarsal spur long and lanceolate (widened basally and pointed apically); last tarsomere expanded, relatively large; hind coxa stout, about 1.57 × along as broad.

Wings. Marginal cell of fore wing with slightly convex to nearly straight radial vein ( Fig. 9 ); hind wing with distal abscissa of Cu1 present, joining cu-a closer to 1A than to M ( Fig. 10 ).

Metasoma. All tergites densely coarsely punctate, especially centrally ( Fig. 11 ), separated by spaces less than puncture diameter especially from T3 and onward. Metasomal T1 about equal in length to its width posteriorly, lateromedian carinae extending to about 0.5 × its length; T2 about 2.0 × as broad as long, lateral sides of T2¯4 weakly biconvex, with moderate grooves between upper and lower corners. Ovipositor about 1.0 × as long as hind tibia, projecting beyond apex of metasoma by 0.17 × length of hind tibia, more or less straight, tapering from its apical 0.1 ( Figs 12 a, 12b).

Colour. ( Fig.7 ). Body (including antenna) dark brown to black, with palpi, tegula, apical half of fore and middle trochanters, apical third of fore femur, fore tibia and tarsus, basal third of mid tibia, mid trochantellus and apical half of mid trochanter, apex of hind coxa, sub-basal fourth of hind tibia all pale yellow; ovipositor sheath dark brown to black (pale brown to yellowish in one specimen), ovipositor reddish brown. Metasomal sternites whitish to pale yellow. Fore wing hyaline with dark veins, pterostigma dark brown. In one specimen thin posterior margins of metasomal tergites golden.

MALE: body length 5.0 mm; length of fore wing 3.0 mm.

Resembles female but legs are somewhat paler in colour, apical third of hind tibia pale yellow; legs with fifth tarsomere slender, not expanded; front coxa globular, pale brown, mid and hind coxae entirely dark brown; antenna with 19 flagellomeres.

Distribution. Austria, Belarus, Belgium, Bulgaria, Canada, former Czechoslovakia, Denmark, Italy, Latvia, Lithuania, Moldova, Mongolia, The Netherlands, Poland, Romania, Russia, Spain, Turkey, USA, Ukraine ( Yu et al. 2012), England ( Shaw 1998; Yu et al. 2012; Broad 2016), Finland ( Hellén 1915 as P. carbonator var. morio ; Yu et al. 2012; Fritzén & Fjellberg 2014), France ( Fonscolombe 1854 as Polysphincta pusilla ; Yu et al. 2012), Germany ( Hartig 1838 as Polysphincta velata ), Hungary ( Kiss 1929 as P. carbonator var. morio ; Yu et al. 2012), Norway, Sweden ( Yu et al. 2012; Fritzén & Fjellberg 2014), Egypt (new record).

Host record: In the present study the wasp specimens are found to be a koinobiont ectoparasitoid of the titanoecid spider Nurscia albomaculata . The young larva develops in a transverse position at the front of the spider's opisthosoma just behind the pedicel ( Figs 1‒4 ). The spider remains alive as the parasitoid larva develops, then it is killed and consumed by the larva before pupation ( Figs 5, 6 ). The mode of parasitism here is similar to that of O. carbonator and O. zephyrus ( Fritzén & Fjellberg 2014) . The hosts of the two Chinese Oxyrrhexis species is unknown ( Liu et al. 2009; Fritzén & Fjellberg 2014).

Nurscia albomaculata is the first spider record not only for Oxyrrhexis carbonator but also for the whole Polysphinctina genus-group. In Egypt, N. albomaculata has been reported from Alexandria, Cairo ( El-Hennawy 2006), northeastern Sinai (Ain Gudeirat), Shebin El-Kom (Menoufiya), Al-Kanater (El-Qalyubia), Ras El-Barr (Damietta governorate) ( El-Hennawy 2009). N. albomaculata is known from Europe, Turkey, Egypt to Central Asia (World Spider Catalog 2017).

Comments. Body colour varied greatly among the studied specimens even between specimens of the same country, the only similarity between all, the presence of ivory colour at base of hind tibia ( Fig. 13 ). The female and male specimens from Finland: resemble Egyptian specimens but differ in the following: female: body length 7.0 mm ( Egypt 5.2‒6.8mm); fore wing 5.5 mm ( Egypt 3.7‒4.0mm); female forewing 6.0 mm ( Egypt female 3.7¯4.0 mm); antenna of female with 24 flagellomeres ( Egypt 18‒20 flagellomeres), male with 21 flagellomeres ( Egypt with 19 flagellomeres); ovipositor black with reddish apical third ( Egypt, reddish along its entire length), ovipositor sheath dark brown to black, dense long setae along its whole length ( Egypt dark brown to paler, with shorter setae along its whole length), ovipositor about 0.7 × hind tibial length ( Fig. 14 ) ( Egypt, relatively longer, about 1.0 × as long as hind tibial length ( Figs 12 a, 12b)).

Because the specimens are rather variable in body colour, size and sometimes in the shape and structure of some body parts ( Fritzén & Fjellberg 2014), we consider the above differences to be intraspecific until further future collections.

Oxyrrhexis carbonator has been reported as a parasitoid of many spider hosts of the families Araneidae , Linyphiidae , Tetragnathidae , Theridiidae and Thomisidae ( Townes & Townes 1960; Shaw 1994; Gauld & Dubois 2006; Yu et al. 2012), and non-spider hosts, examples Bupalus piniaria (Linnaeus) ( Lepidoptera : Geometridae ) ( Hartig 1838 as Polysphincta velata ; Yu et al. 2012), Saperda populnea (Linnaeus) ( Coleoptera : Cerambycidae ), Heterarthrus microcephalus (Klug) ( Hymenoptera : Tenthredinidae ) ( Yu et al. 2012). This wide range of hosts may attributed to the fact that the name “ Polysphincta carbonator ” has been wrongly applied to almost any species belonging to Polysphincta genus‒ group ( Shaw 1994).

Figures

FIGURES 5 - 8. 5. Cocoon formation by last larval instar; 6. Pupa of O. carbonator; 7. Lateral habius of female O. carbonator; 8. Lateral habitus of female Polysphincta velata (type) (ZSM-HYM- 000001) by Stefan Schmidt (Munich).

FIGURES 9 - 11. O. carbonator, ♀: 9. Fore wing; 10. Hind wing (part); 11. Dorsal view of metasoma.

FIGURES 12 - 14. O. carbonator: 12 a, b. Ovipositor (Egyptian specimens, ♀); 13. Lateral view of metasoma and hind leg (European specimen, ♀); 14. Ovipositor (European specimen, ♀)

FIGURES 1 - 4. Developmental larval stages of Oxyrrhexis carbonator on Nurscia albomaculata spider.