Eurytenes abnormis (Wesmael)

Walker, Andrea K. & Wharton, Robert A., 2011, A review of New World Eurytenes s. str. (Hymenoptera, Braconidae, Opiinae), Journal of Hymenoptera Research 20, pp. 23-46 : 28-32

Eurytenes abnormis (Wesmael) Figs 4 8-14 31

Opius abnormis Wesmael 1835: 117. ♀♂ Syntypes in Brussels.

Opius abnormis : Haliday 1837: 204 (redescription, habitat); Ratzeburg 1848: 62 (diagnosis, hosts).

Eurytenes abnormis : Foerster 1862: 259 (genus description in key, abnormis as type species); Taschenberg 1866: 79, 87 (key, diagnosis); Marshall 1872: 122 (British catalog); Marshall 1891: 16-17 (redescription, English); Marshall 1894: 283-284, 291-292 (key, redescription, French); Dalla Torre 1898: 67 (catalog); Szépligeti 1904: 159, 163 (key, catalog); Niezabitowski 1910: 89 (distribution, brief characterization); Fischer 1959: 248-250 (redescription, hosts); Fulmek 1962: 47-50 (hosts); Fischer 1965: 165-167 (redescription, North American distribution); Fischer 1972: 472-475 (monograph); Marsh 1979: 202 (North American catalog); Papp 1985: 344-345 (color variation, distribution); Tobias and Jakimavicius 1986: 8, 96-98 (redescription in key, distribution); Tobias 1998 (redescription in key, distribution); Yu et al. 2005 (electronic catalog).

Material examined.

♀♂, BELGIUM: vicinity of Brussels, v.18??, C. Wesmael (syntypes, Brussels). 1 ♀, ENGLAND: Sheffield, 16-17.viii.1991, R. Wharton (TAMU). 1 ♀, HUNGARY: Protected forest, 13.vi.1974, Hámoriné & Marótiné (TAMU). IRELAND: 3 ♀, Co. Sligo, Trawalua,10.vii.1936 & 2.viii.1938, A.W.Stelfox (USNM); 1 ♀, Co. Wicklow, Manor Kilbride, 19.vii.1950, A.W. Stelfox (USNM).

Diagnosis.

Eurytenes abnormis is most readily recognized by the pale coloration of the petiole and metasoma and is further distinguished from the four North American species described below by the narrower, more ventrally concave clypeus ( Fig. 10 ). The petiole is narrower than in Eurytenes dichromus , sp. n. and Eurytenes microsomus , sp. n. and is thus more similar in shape to the darker Mexican species described below.

Description

(♀). Length of body: 1.9-2.4 mm (m=2.2), length of fore wing 2.3-3.0 mm (m=2.7).

Head. 27-31 flagellomeres; first flagellomere length 4.0-5.0 × width (m=4.4), fifteenth flagellomere length 2.0-3.5 × width (m=2.9), fifth from last flagellomere length 2.2-3.0 × width (m=2.7). Face 1.4-1.7 (m=1.5) × wider than high. Clypeus broadly chevron-shaped, with ventral margin concave; 2.0-3.0 (m=2.5) × wider than high; 1.3-1.8 (m=1.5) × wider than distance between clypeus and eye. Mandible distinctly expanded over basal 0.3, with flange-like ventral carina. Gena relatively narrow ( Fig. 8 ). Occipital carina dorsally extending about 0.6-0.7 × distance from eye to nearest lateral ocellus.

Mesosoma. Posterior-ventral margin of lateral pronotum crenulate for most of length. Precoxal sulcus parallel-sided, narrowly crenulate along most of length, usually weakly impressed anteriorly, often extending very close to anterior margin of mesopleuron; precoxal sulcus inclined at a 35 degree angle. Notaulus distinctly impressed over anterior third of mesoscutal disc, crenulate over anterior 0.2-0.3; with cluster of short setae at rugulose base of anterior declivity; with widely spaced line of 3-5 longer setae extending posteriorly towards but not usually reaching cluster of scattered setae around midpit. Propodeum with median carina present anteriorly, bifurcating near middle to form five-sided median areola over posterior 0.6, surface rugose laterally and posterior-medially, partly obscuring areola, but posterior-lateral fields largely smooth, as in Fig. 11 .

Wings. Fore wing r-m tubular and pigmented only at extreme anterior end, otherwise unpigmented, with lateral boundaries often only weakly indicated; (RS+M)b absent, m-cu entering extreme base of second submarginal cell; 3M very weakly pigmented basally in available material, spectral over most of length. Hind wing m-cu varying from indistinct in smaller individuals to present as a spectral impression extending more than half way to wing margin in larger individuals.

Legs. Hind tibia 7.5-9.3 (m=8.7) × longer than maximum width.

Metasoma. Petiole 1.9-2.2 (m=2.0) × longer than apical width. Female ovipositor short but distinctly protruding, about 0.9 × length of mesosoma. Ovipositor sheath about 0.4 × length of mesosoma.

Color. Head and mesosoma dark reddish-brown to black. Scape, pedicel and first flagellomere yellow, antenna quickly darkening distally to dark brown; palps and tegula pale yellow; mandible and petiole tawny (darker yellow). Metasoma posteriad petiole usually bright yellow, sometimes with faint slight butterscotch banding to lighter brown banding. Hind femur and tibia darkening distally, femur transitioning from yellow to dark yellow or yellow-brown, tibia mostly infuscated, tarsi infuscated; legs otherwise yellow. Ovipositor sheath dark brown to black; ovipositor light brown throughout. Wings hyaline.

Host Records.

Fischer (1959) listed 12 species of Agromyzidae , one Anthomyiidae , and one microlepidopteran as hosts but with no records of host plants. In this publication Fischer also noted that the anthomyiid and especially the microlepidopteran host ( Coleophora nigricella Rondani) need verification. Fischer (1964) added four more dipterans to the list and later ( Fischer 1969a, b) provided additional records, including host plant information for nearly all of the known hosts. Nomenclatural updates for agromyzids and plant hosts from Fischer (1972) and Yu et al. (2005) are incorporated in the list of confirmed hosts given below, with additional updates from Ellis (2007). Host plants for these 23 agromyzid hosts are split unevenly between monocots (8 fly species) and dicots (15 fly species). Four of the host fly species were reared from Asteraceae and four from Poaceae , whereas Lamiaceae , Ranunculaceae , and Cyperaceae each harbored three host fly species.

The agromyzid host records found in ( Fischer (1964, 1969a, b) have a relatively high degree of confidence because these records pertain to rearings by Buhr, Groschke, and Nowakowski, respectively. Fischer identified the Eurytenes reared from these hosts (specimens in NHMW) and the hosts and host plants correspond well with information in Ellis (2007). Earlier literature, and several compilations based on the earlier primary sources, are problematic, however, because of the potential for misidentification of the wasp and/or host fly, as well as the absence of voucher specimens. We follow Fischer (1959) and treat the published host records for Pegomya bicolor (Wiedemann) ( Diptera : Anthomyiidae ) and Amauromyza verbasci ( Bouché) dating to Bouché (1834), Ratzeburg (1848), and Rondani (1872) as almost certainly erroneous and likely based on misidentification of the other opiines that routinely attack these hosts or possibly on misidentification of the host. Records of non-dipteran hosts are clearly erroneous since members of the Opiinae are all parasitoids of cyclorrhaphous Diptera .

Host: Plant.

Agromyza albitarsis Meigen: host plant for Eurytenes abnormis has not been recorded previously but since this fly is known to attack several trees in the family Salicaceae , the record may need to be verified;

Agromyza woerzi Groschke: Knautia arvensis (L.) Coult, Caprifoliaceae ;

Amauromyza labiatarum (Hendel): Galeopsis tetrahit L., Lamiaceae ;

Amauromyza lamii (Kaltenbach): Lamiastrum galeobdolon (L.), Lamiaceae ;

Cerodontha angulata (Loew): Carex hirta L., Cyperaceae ;

Cerodontha caricivora (Groschke): Carex hirta L., Cyperaceae ;

Cerodontha eucaricis Nowakowski: Carex hirta L., Cyperaceae ;

Cerodontha flavocingulata (Strobl): Festuca pratensis Huds. (= Lolium pratense ) and Holcus lanatus L., Poaceae ;

Cerodontha incisa (Meigen): Alopecurus pratensis L. and Phleum pretense L., Poaceae ;

Cerodontha iraeos (Robineau-Desvoidy): Iris pseudacorus L., Iridaceae ;

Cerodontha pygmaea (Meigen): Dactylis glomerata L. and Deschampsia cespitosa (L.), Poaceae ;

Liriomyza balcanica (Strobl): host plant for Eurytenes abnormis has not been previously recorded but this fly is known to attack members of the Euphorbiaceae ;

Liriomyza demeijerei Hering: Artemisia vulgaris (L.), Asteraceae ;

Liriomyza eupatoriana Spencer: Eupatorium cannabinum L., Asteraceae ;

Liriomyza flaveola ( Fallén): Festuca pratensis Huds., Poaceae ;

Liriomyza scorzonerae Rydén: Scorzonera humilis L., Asteraceae ;

Phytoliriomyza variegata (Meigen): host plant for Eurytenes abnormis has not been previously previously but this fly is known to attack members of the Fabaceae ;

Phytomyza abdominalis Zetterstedt: Hepatica nobilis Mill., Ranunculaceae ;

Phytomyza albimargo Hering: host plant for Eurytenes abnormis has not been recorded previously but this fly is known to attack Anemone in the Ranunculaceae ;

Phytomyza fallaciosa Brischke: Ranunculus repens L., Ranunculaceae ;

Phytomyza obscura Hendel: Clinopodium vulgare L., Lamiaceae ;

Phytomyza pulmonariae Nowakowski: Pulmonaria angustifolia L., Boraginaceae ;

Phytomyza senecionis Kaltenbach: Senecio nemorensis fuchsii (= Senecio fuchsii Celak), Asteraceae .

Distribution.

Previously recorded from throughout most of Europe (specifically Austria, Belgium, Bulgaria, Croatia, England, Finland, Germany, Hungary, Ireland, Italy, Lithuania, Poland, western Russia as far as the Urals, and Ukraine). Also recorded from eastern Palaearctic (Korea and Sakhalin Island), central to eastern Canada (Ontario, Saskatchewan) and USA (Minnesota, Missouri, North Dakota, South Carolina). Specific references to individual records can be found in Yu et al. (2005) for the most part; the record from the Urals is from Tobias and Jakimavicius (1986). Fischer (1970) recorded Eurytenes abnormis from Montana; however, the specimen on which it is based was collected in Missouri (label information only indicated the state as Mo.). The records from Sakhalin ( Tobias 1998) and Korea ( Papp 1985) may need to be verified in light of other species described from that general region. The specimens we have examined from Taiwan and the Kuril Islands differ in wing venation, body coloration, and sculpture from typical Eurytenes abnormis . Papp (1985) also noted the darker coloration of the petiole of his Korean specimen.

Comments.

Fischer (1972) treated Opius paradoxus Ratzeburg, 1848 as a nomen nudum, while Dalla Torre (1898) listed it with a query as a synonym under Eurytenes abnormis , undoubtedly following Marshall (1891). Ratzeburg (1848), in his treatment of Opius , separated abnormis from all other species on the basis of the wing venation features that we now use to define Eurytenes s. str. Ratzeburg (1848) initially states that only a single species, abnormis, belongs to the section of Opius with the radius arising from the base of the stigma. In the following sentence, however, Ratzeburg introduces the name paradoxus, indicating that it also should be placed here. Though this can be interpreted to mean that Ratzeburg was treating paradoxus as a synonym of abnormis, nevertheless he also mentioned body coloration (dark) and clypeal characters (lack of opening between clypeus and mandibles) that differ from typical abnormis. Ratzeburg referred to Bouché throughout when discussing paradoxus and abnormis, and at the end of his treatment gives information on a more typical pale specimen of abnormis reared by Bouché. Whether intentional or otherwise, it would appear that Ratzeburg (1848) did provide a valid description of paradoxus with two characters that could be used to differentiate it from abnormis. However, his text could just as easily be interpreted to mean that paradoxus is invalid since it was first proposed as a synonym of abnormis. We prefer the latter interpretation.

Wu and Chen (2006) were the first to use morphological features other than color for discriminating between species of Eurytenes s. str. They used propodeal sculpture and the extent of the precoxal sulcus to differentiate their newly described Eurytenes basinervis from Eurytenes orientalis . Previously, ( Fischer (1966, 1998) used only color differences to distinguish between Eurytenes orientalis and Eurytenes abnormis . We have noted differences among species in the shape of the clypeus, but the appearance of the ventral margin of the clypeus changes with angle of view, and the differences are subtle. All species appear to have a concave ventral margin if the ventral part of the head is strongly rotated anteriorly. When placed in the same plane of view, however, the clypeus of the New World species described here is more truncate ventrally than that of Eurytenes abnormis .

In addition to specimens listed in the material examined section above, two specimens from Poland and one from Germany (NHMW) were also briefly examined; data for these specimens were previously recorded by Fischer (1969a, b). In our summary of references above, we have not included several papers that provide only distribution information. These can be found in Yu et al. (2005).

Figures

Figures 4 - 7. Eurytenes spp., habitus. 4 Eurytenes abnormis, female 5 Eurytenes ormenus sp. n., female 6 Eurytenes pachycephalus sp. n., male 7 Eurytenes dichromus sp. n., female.

Figures 8 - 14. Eurytenes abnormis. 8 Head, lateral view 9 Mesosoma, lateral view, arrow = precoxal sulcus 10 Face 11 Propodeum, posterior view 12 Left fore and hind wing 13 Petiole, dorsal view, arrow = dorsope 14 Petiole, lateral view.

Figures 30 - 31. 30 Eurytenes dichromus sp. n., mesoscutum, dorsal-lateral oblique, arrow = notaulus 31 Eurytenes abnormis, mesosoma, dorsal view, arrow = scutellar sulcus.