Bracon (Glabrobracon) discoideus Wesmael 1838
Creators: name: Papp, Jenő
name: Xviii, Budapest
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Braconidae
Bracon
Bracon discoideus

description: Bracon (Glabrobracon) discoideus Wesmael, 1838
Figs 5 B-K, 6A-C
Braco discoideus Wesmael, 1838: 45 ♀ (type material: four ♀♀), type locality: “environs de Bruxelles ” (Belgium), ♀ lectotype (and three ♀ paralectotypes, present designations) in the Royal Belgian Institute of Natural Sciences, Brussels; examined.
Bracon discoideus – Szépligeti 1901: 267 (in key, in Hungarian); 1904 (1901): 177 (in key, in German). Bracon (Glabrobracon) discoideus - Fahringer 1927: 261 (♀), 290 (♀), 304 (♁) (in key) and 1928: 455 (redescription), assigned to ”Section Glabrobracon ”. — Telenga 1936: 151 (♀) 155 (♁) (in key), 219 (redescription) (in Russian) and 354 (♀), 358 (♁) (in key, in German). — Shenefelt 1978: 1567 (literature up to 1974). — Tobias 1986: 134 (supposed synonymy with B. variator Nees, in footnote).
Designation of the ♀ lectotype of Bracon discoideus
(First label, printed) “ Coll. Wesmael ”, (second label, printed) “2058”, (third label) “ Braco discoideus mihi ♀ ” (handwritten) “dét. C. Wesmael ” (printed), (fourth label, printed red) “ Type ”, fifth label is with the inventory number “3.317”, sixth label is the locality card “ Belgique / Bruxelles ” attached by me, seventh label is the lectotype card. Lectotype is in poor condition: (1) head with antenna missing, (2) costal / subcostal vein of right fore wing medially damaged.
Designations of the three paralectotypes of Bracon discoideus
All three specimens with similar labels to those of the lectotype. First paralectotype is in poor condition: (1) metasoma missing; (2) both antennae damaged, right flagellum with 13 and left flagellum with 15 flagellomeres; (3) hind right leg entirely and distal two-thirds of fore left wing missing. Second paralectotype is in less poor condition, missing: left antenna (right antenna not damaged, with 23 flagellomeres), tarsus of right middle leg and left hind leg (except coxa + trochanters).Third paralectotype is in very poor condition: (1) head and metasoma missing; (2) left fore wing missing; (3) left hind leg, left middle leg (except coxa) and tarsomeres 2-5 of left fore leg missing (i.e. present are only the three right legs).
Material examined
39 ♀♀ + 5 ♁♁ from eleven countries: SCOTLAND: 7 ♀♀ from four localities. ENGLAND: 9 ♀♀ + 1 ♁ from nine localities. THE NETHERLANDS: 1 ♀. FRANCE:1 ♁. GERMANY: 8 ♀♀ + 1 ♁ from nine localities. AUSTRIA: 1 ♀. BOHEMIA: 1 ♀ + 1 ♁ from two localities. SLOVAKIA: 1 ♁. HUNGARY: 7 ♀♀ from seven localities. ITALY: 3 ♀♀ from three localities. BULGARIA: 2 ♀♀ from two localities.
Redescription of the ♀ lectotype of Bracon discoideus
HEAD. Missing
LENGTH. Body, or meso- and metasoma combined, 2.3 mm long.
The following description is based on one ♀ specimen identical to the ♀ lectotype (taken in Italy, Riva s. Garda, 150 m, G / 10 Sep. 67, leg. Haeselbarth; specimen in the Budapest Museum).
LENGTH. Body length is 2.5 mm.
ANTENNAE. Somewhat shorter than body, right antenna with 23 and left antenna with 22 antennomeres. First flagellomere 2.3 times, further flagellomeres gradually shortening so that penultimate flagellomere 1.8 times as long as broad.
HEAD. In dorsal view transverse (Fig. 5B), 1.75 times as broad as long, eye 1.4 times as long as temple, temple rounded, occiput excavated. Eye in lateral view one-fourth wider than width of temple beyond eye (Fig. 5C, see arrows). Oral opening usual in size, its horizontal diameter 1.4 longer than shortest distance between opening and compound eye (Fig. 5D). Head polished. Antenna and head black, oral opening and oral organs yellow.
MESOSOMA. In lateral view 1.4 times as long as high, polished. Notaulix weakly distinct. Propodeum polished, close above lunule with short crenulae (Fig. 5E).
LEGS. Hind femur 3.8 times as long as broad (Fig. 5F). Claw downcurved, its basal lobe pointed (Fig. 5G).
WINGS. Forewing about one-third longer than meso- and metasoma combined. Pterostigma (Fig. 5H) wide, 2.75 times as long as wide, issuing r proximally from its middle, r somewhat shorter than width of pterostigma; submarginal cell fairly long, 3-SR 1.45 times as long as 2-SR, SR1 straight, 1.6 times as long as 3-SR and reaching tip of wing (Fig. 5H). First discal cell fairly high, 1-M 1.9 times as long as m-cu, 1-SR-M almost straight and 1.35 times as long as 1-M (Fig. 5I).
TERGITES (Fig. 5J). First tergite somewhat longer than broad behind, pair of spiracles before middle of tergite, beyond spiracles tergite slightly broadening; tergite laterally from scutum crenulate. Scutum together with further tergites polished. Second tergite 2.7 times as broad behind as long, suture between tergites 2-3 weakly bisinuate. Second tergite somewhat longer than third tergite. Hypopygium pointed, end of ovipositor as in Fig. 5K.
COLOUR. Mesosoma brownish black, tegula yellow. First tergite brownish, ground colour of tergites testaceous, medially with faint brownish streak. Sternites pale yellow. Legs yellow, hind coxa faintly brownish. Wings brownish subfumous, pterostigma brownish, veins light brownish.
Variable features of the ♀ (39 ♀♀)
Body (2-)2.5-2.8(-3.2) mm long. Antenna with 21-31, usually 24-26, antennomeres. Penultimate flagellomere (1.6-)1.7-1.8 times as long as broad. Head in dorsal view (1.7-)1.8-1.9 times as broad as long, temple somewhat receded (2 ♀♀, cf. Fig. 64D). Pterostigma wide, 2.4 times as long as wide (5 ♀♀, cf. Fig. 42D); second submarginal cell long, 3-SR 1.7-1.8 times longer than 2-SR (3 ♀♀, Fig. 6A). Metasoma somewhat less broad, second tergite 1.3 times longer medially than third tergite also medially (7 ♀♀, Fig. 6B); second tergite antero-medially longitudinally rugulose (4 ♀♀, Fig. 6C, cf. Figs 12H; 64H). Ovipositor sheath long, as long as hind tibia + tarsus combined (2 ♀♀).
Description of the ³ (5 ³³)
Body 2.6-3.2(-3.8) mm long. Antenna about as long as to somewhat longer than body and with 27-29 antennomeres. Flagellomeres long, 1.7-2 times longer than broad. Head in dorsal view 1.75-1.8 times as broad as long; temple either rounded (Fig. 5B) or slightly receded (cf. Fig. 12I). Fore wing: 3-SR 1.35- 1.45 times as long as 2-SR. First tergite 1.2 (cf. Fig. 42F) to 1.3 times (cf. Fig. 38H) as long as broad behind.
Hosts
COL. Cerambycidae:? Saperda populnea Linnaeus. Curculionidae: Anthonomus pomorum Linnaeus, Balanobius pyrrhoceras Marsham, Ceutorhynchus quadridens Panzer, Curculio crux Fabricius, C. nucum Linnaeus, C. salicivorus Paykul, Pissodes notatus Fabricius, Rhynchites pauxillus Germar. Attelabidae: Byctiscus betulae Linnaeus, B. flavipes Ratzeburg, B. populi Linnaeus. — LEP. Heliozelidae: Heliozela sericella Haworth. Lithocolletidae: Phyllono-rycter rajella Linnaeus. Tortricidae: Adoxophyes orana Fischer von Röslerstamm, Eulia ministrana Linnaeus, Rhyacionia buoliana Denis et Schiffermüller. — DIPT. Agromyzidae:? Agromyza lateralis Fallén. Chloropidae:? Chlorops pumilions Bjerk. — HYM. Tenthredinidae: Nematus salicis Linnaeus, N. viminalis Linnaeus,! Pontania bridgmanni Cameron,! P. foetidae Kopelke,! P. pedunculi Hartig,! P. proxima Lepeletier,! P. varia Kopelke. Cynipidae: Biorrhiza pallida Olivier.
Distribution
Western Palaearctic Region.
Taxonomic position
Within the subgenus Glabrobracon the following species form the Bracon discoideus species-group characterized by the long second tergite (i.e. second tergite longer than third tergite): B. batis Papp (Hungary), B. discoideus Wesmael (western Palaearctic Region), B. epitriptus Marshall (Palaearctic Region), B. pulcher Bengtsson (Sweden, Denmark, Germany, Austria, Poland, Hungary) and B. subsinuatus Szépligeti (Europe). The five species are distinguished by the following key features:
1 (4) Head in dorsal view less transverse, 1.6-1.7(-1.75) times as broad as long, temple usually strongly rounded (Fig. 6H) to receded (Fig. 6D).
2 (3) Hind femur 2.9-3 times as long as broad medially (Fig. 6E). Claw less downcurved (Fig. 6F). Second tergite clearly, 1.3 times longer laterally than third tergite medially, smooth (Fig. 6G). Pterostigma yellow. ♀: 3.7 mm ........................................................................................ B. (Gl.) batis Papp, 1981
3 (2) Hind femur 3.5-4 times as long as broad more or less distally (Fig. 6I). Claw downcurved (Fig. 6J). Second tergite slightly longer than third tergite, anteriorly more or less rugulose(-rugose) (Fig. 6K). Pterostigma brown to light brown. ♀ ♁: 2.6-4.5 mm ........................... B. (Gl.) epitriptus Marshall, 1885
4 (1) Head in dorsal view transverse, (1.7-)1.8-1.9 times as broad as long, temple either rounded or receded (Figs 5B; 7B, D).
5 (6) Scutum of first tergite broad, i.e. rim of first tergite narrow and densely crenulated (Fig. 7C). Ovipositor sheath long, twice longer than hind tibia + basitarsus combined. Pronotum and mesoscutum blackish with yellow or reddish yellow pattern. ♀ ♁: 2.5-3.5mm ........... B. (Gl.) pulcher Bengtsson, 1924
6 (5) Scutum of first tergite less broad, i.e.rim of first tergite less narrow and less densely crenulated (Figs 5J; 7E). Ovipositor sheath less long, at most as long as hind tibia + basitarsus combined. Mesosoma entirely black.
7 (8) Second tergite somewhat(1.1-1.2 times) longer than third tergite, usually polished (Fig. 5J), at most finely sculptured anteriorly(Fig.6C).Temple in dorsal view rounded(Fig.5B). Hind femur3.6-3.8 times as long as broad (Fig. 5F). Claw somewhat more downcurved (Fig. 5G). ♀ ♁: (2-) 2.5-3.2 mm .......... ........................................................................................................ B. (Gl.) discoideus Wesmael, 1838
8 (7) Second tergite clearly (1.3-1.4 times) longer than third tergite; second tergite anteriorly sculptured (Fig. 7E). Temple in dorsal view rather receded (Fig. 7D). Hind femur 3-3.1 times as long as broad (Fig. 7F). Claw somewhat less downcurved (Fig. 7G). ♀ ♁: 2.5-3.5 mm ............................................. ...................................................................................................... B. (Gl.) subsinuatus Szépligeti, 1901
description: Published as part of Papp, Jenő & Xviii, Budapest, 2012, A revision of the Bracon Fabricius species in Wesmael's collection deposited in Brussels (Hymenoptera: Braconidae: Braconinae), pp. 1-154 in European Journal of Taxonomy 21 on pages 16-20, DOI: 10.5852/ejt.2012.21, http://zenodo.org/record/3858161