Telenomus americanus, (Brues)

Popovici, Ovidiu Alin, Masner, Lubomír, Viciriuc, Mădălina, Pintilioaie, Alexandru, Notton, David G. & Talamas, Elijah, 2018, New distribution data for some charismatic tramp species of Platygastroidea (Hymenoptera), Zootaxa 4370 (1), pp. 1-22 : 6-10

Tetrabaeus americanus (Brues)

http://bioguid.osu.edu/xbiod_concepts/23277 Figures 7–24 , 47

Aphanomerus americanus BRUES, 1909: 156 (ORIGINAL DESCRIPTION); NOONAN 1984: 6 (TYPE INFORMATION).

Tetrabaeus americanus (BRUES) : KIEFFER 1912: 87 (GENERIC TRANSFER); KIEFFER 1926: 138 (DESCRIPTION); MASNER 1964: 149 (SYNONYMY, TYPE INFORMATION); VLUG 1995: 83 (CATALOGED, TYPE INFORMATION).

Crabroborus krombeini MUESEBECK, 1963: 392 (ORIGINAL DESCRIPTION); MASNER 1964: 149 (JUNIOR SYNONYM OF Tetrabaeus americanus (BRUES)); NOONAN 1984: 6 (TYPE INFORMATION).

Tetrabaeus krombeini (MUESEBECK): MASNER & MUESEBECK 1968: 79 (TYPE INFORMATION); VLUG 1995: 83 (TYPE INFORMATION).

Material Examined. NORTH AMERICA: CANADA: 1♀, Ontario, Woodlawn , 45.49361°N, 76.11083°W, 19– 26.vi.2015, leg. J.D. Read (MT; OPPC) ; 1♂, Ontario, Petrie Island , 45.50141°N, 75.49648°W, 19–24.vi.2015, leg. H. Goulet & L. Masner ( YPT; OPPC) ; 1♀, Quebec, Parc Gatineau, Ridge Road , 3.vi.1980, leg. L. Masner (screen sweeping: CNCI) ; 1♀, New Brunswick, Kouchibouguac N.P., 30.viii.1977, leg. S.J. Miller ( CNCI) . USA: 1♀, Hawai’i Island, Waimea Parker Ranch Forest , 20.01095°N, 155.3452°W, 22–29 vi.2005 leg. Luc Leblanc ( CNCI) ; 1♀, Indiana, Porter Co., Dune Acres , 16.x.1948, leg. H.S. Dybas (MT: CNCI) ; 1♀, Kentucky, Scott Co. 234 Finnell Pike , 38.284°N, - 84.451°W, leg. Lindsay & Edden (MT: CNCI); 1♀, Maryland, Prince George Co., 39.050°N, - 76.783W, 1–8.VI.1992, leg. J. Pickering (MT: CNCI); 1♀, Michigan, Ann Arbor , 23.viii.1982, leg. M. Sharkey ( CNCI) ; 1♀, North Carolina, Swain Co. Andrews Bald , 35.536°N, - 83.494°W, leg. I.C. Stocks (MT: CNCI). MEXICO: 1♀, Puente Nacional , Veracruz, 12.vii.1960, leg. H. Howden ( CNCI) .

EUROPE: UKRAINE: 6♀, Transcarpathia, Tyachiv district, 6.5 km n. of Mala Ugolka , 22.v– 8.vi.2015, 48.260994°N, 23.6169°E, leg. O. Varga (MT; OPPC) ; 2♀, Transcarpathia, Svydovets, 2–3 km n. w. of Kvasy , 22.v–8.vi.2015, 48.152469°N, 24.266208°E, leg. O. Varga (MT; OPPC) ; 1♀, Transcarpathia, Svydovets, 2–3 km n. w. of Kvasy , 7.v–5.vi.2014, 48.152469°N, 24.266208°E, leg. O. Varga (TT; OPPC) ; 2♀, Transcarpathia, Svydovets, 2–3 km n. w. of Kvasy , 5–29.vi.2014, 48.152469°N, 24.266208°E, leg. O. Varga (TT; OPPC) ; 1♀, Transcarpathia, Mochary, 5 km n. e. of Bogorodchany , 16.vi–4.vii.2014, 48.847547°N, 24.590808°E, leg. O. Varga (MT; OPPC) . GEORGIA: 5♀, Lagodekhi Reserve, Mt. Kudigora , 41.90619°N, 46.33344°E, 26.vii–3.viii.2014, alt. 2230 m, G. Japoshvili & G. Krikitadze ( CNCI) .

ASIA: JAPAN: 1♀, Hokkaido, Sapporo Jozankei , 20–31.vii. 1989, M. J. Sharkey (MT; CNCI) ; 1♀, Kyushu, Fukuoka, Mt. Hiko alt. 700 m, 26.ix.–2.x.1989, K. Takano & M. Sharkey (MT; CNCI) . SOUTH KOREA: 1♂, Kangwondo, Cuncheon Nam-myeon, Hudong-li, 17.viii–5.ix.2003, leg. P. Tripotin (MT; OPPC) ; 1♀, Kangwondo, Cuncheon Nam-myeon, Hudong-li, 25.v–14.vi.2003, leg. P. Tripotin (MT; OPPC); 4♀, Kangwondo Chuncheon Nam-myeon Hudong-li , vi–ix. 2003, leg. P. Tripotin, (MT; CNCI) ; 2♀, Chungbuk Yeondong-gun, Sangchonmyon, Mulhan Valley, Gojadong , 4.vi–24.ix.2002, P. Tripotin (MT; CNCI) .

Comments. The monotypic Tetrabaeus was previously only recorded from North America (Brues 1909; Kieffer 1912, 1926; Muesebeck 1963; Masner 1964; Vlug 1995).

It is difficult to determine if T. americanus is a recently introduced species in the Palaearctic region or a native one that has been unrecorded until now. Masner (unpublished data), examined some specimens of this species in HNHM, collected from Hungary and labeled as Aphanomerus (as noted in the Results section, striae on T2 are usually present but difficult to see without good optics and are only rarely absent). These specimens are seemingly lost because OAP was not able to locate them in the HNHM during his recent visit.

Because this species was also found in samples from Georgia, South Korea and Japan, we consider the possibility that Tetrabaeus is a Holarctic genus.

Although the descriptions of Muesebeck (1963) and Masner & Huggert (1989) provide clear limits of this species, we here augment these descriptions with the addition of new data on variability and clear images of the morphology.

Description. Female. Colour: Most specimens are black or dark brown, but also there are specimens with black head and mesosoma and dark brownish metasoma. Antenna light brown, in many specimens with yellow A3–A5 and brown clava, but in some specimens the entire antenna is light brown with a darker clava. Legs with coxae brown and tibiae and tarsi yellow; femora lighter than coxae and darker than tibiae and tarsi.

Head in dorsal view wider than long, subellipsoidal with a coriaceous-imbricate sculpture and sparse long hairs; frons dorsal to toruli with alutaceous sculpture; frons medially smooth, almost without sculpture; hyperoccipital carina absent; occipital carina present, complete medially; postgenal sulcus and median sulcus of the postgenal bridge absent; postgenal pit present; eyes appear glabrous, but under high magnification with short, fine scattered hairs; interantennal process not prominent, deeply concave; clypeus very narrow, with a row of strong and long setae; maxillary palp 2-segmented; labial palp 1-segmented; antenna 7-segmented, with abrupt, massive, compact 4-segmented clava, sensillar formula 1:2:2:2.

Mesosoma with pronotal shoulders strongly developed, clearly visible in dorsal view; mesoscutum and mesoscutellum with fine coriaceous sculpture; parapsidal line absent; notauli percurrent, deeply incised, broadened and convergent posteriorly; transaxillar carina and axillular carina not fused, both clearly visible; posterior mesoscutellar sulcus deep and wide, clearly visible on lateral sides of mesoscutellum, but superficial or absent on medio-posterior part of mesoscutellum; metanotum narrow, smooth, not foveolate; metascutellum hardly visible, with no sculpture or pilosity; propodeum with no foamy structure, hairy at sides, glabrous in middle, with two clearly visible, parallel lateral propodeal carinae; metasomal depression large, glabrous; propodeal spiracle clearly visible; transverse pronotal sulcus shallow and glabrous only in the median part, on ventral and dorsal third covered with short hairs; lateral propleural area with a large, deep and glabrous depression; netrion rudimentary, hardly visible; transaxillar carina in lateral view with numerous longitudinal striae; mesopleuron smooth, almost glabrous, with a clearly visible, rather deep mesopleural depression; pleural pit well visible; transpleural sulcus almost transverse, deep and sharply incised, interrupted in the median part; speculum with some transverse costae; metapleuron not sculptured, covered with sparse long hairs; clearly visible metapleural pit; metapleural sulcus weak; metapleural carina well developed; fore wing with a straight tubular submarginal vein and truncate knob and with nebulous RS+M, M and Cu (hardly visible); costal and submedian cells glabrous; submarginal vein without setae; hind wing with short stem of tubular submarginal vein, apically with some setae; legs relatively short with femora thickened; tibial spur formula 1-2-2 and fore spur bifid.

Metasoma not longer than head and mesosoma combined, convex dorsally, with 6 visible tergites; T1 trapezoidal, without horn; anterior pits of T1 clearly visible, the space between these pits with strong costae, the length of these costae not surpassing the posterior border of anterior pits of T1; laterally, in the area of the anterior pits, T1 is covered with sparse long setae, but in middle, in the area with sculpture it is glabrous; T2, the largest tergite, smooth, with anterior pits clearly visible with some hairs; the space between the anterior pits of T2 with strong costae, protruding over T1; T3–T6 without sculpture, with few hairs, usually in a single transverse row; laterotergites present, well developed, almost ¼ maximum width of T2; ventrally metasoma with numerous hairs, especially on S1 and S2; anterior pits of S2 converging in a single transverse depression covered with dense hairs; the felt field of S2 indicated only by distinct microsculpture, not with dense pilosity.

Male: similar to female, differing in the structure of antenna, clava less abrupt, limits between clavomeres more clearly marked than in female, A4 longer than A3 and metasoma consisting of 8 visible tergites with a rounded apex (apex rather obtuse in female).

Our specimens represent a new record for the Palaearctic ( Ukraine, Georgia and South Korea) and Sino- Japanese regions ( Japan). Also, Tetrabaeus is a new record for Canada and Mexico (in the last case being found very close to the Panamanian region).

Morphological variability. We consider that all of the examined specimens belong to the same species, T. americanus . We concluded this from a comparison of our specimens with specimens from the Nearctic. Regarding colour variability, we consider that the collecting method and preservation conditions (e.g. ethanol concentration, temperature, duration of time in trap) have an influence. The influence of the preservation conditions on the colour of insects was also emphasized by Noyes (1982), Masner (1994) and King & Porter (2004). Specimens in which the metasoma is paler also have this part of the body inflated, suggesting that these specimens have been bleached and distorted by prolonged storage in ethanol (O. Popovici, pers. obs.). We did not find a correlation between geographical distribution and colour.

Another variable character we observed is the length of the costae on T2. The longest costae are in specimens from Canada and the costae are absent from a male specimen from South Korea.

Masner & Huggert (1989) considered the sculpture of T2 important in the delimitation of the genera with 7 or 8 antennomeres, and with compact clava. The presence of the longitudinal costae/striae on T2 divide this group of genera into two subgroups: Pseudaphanomerus Szelényi, Calomerella Masner & Huggert , Aphanomerella Dodd and Tetrabaeus Kieffer , (costae present) and Aleyroctonus Masner & Huggert , Helava Masner & Huggert , Alfredella Masner & Huggert , and Aphanomerus Perkins (costae absent).

Figures

FIGURES 7–12. INTRASPECIFIC VARIABILITY IN Tetrabaeus americanus: 7, 8. FEMALES FROM UKRAINE; 9. FEMALE FROM CANADA;10. FEMALE FROM S. KOREA;11. MALE FROM CANADA;12. MALE FROM S. KOREA.

FIGURES 13–17. Tetrabaeus americanus: 13. FEMALE ANTENNA–LIGHT MICROSCOPY; 14. MALE ANTENNA–SPECIMEN FROM CANADA; 15. MALE ANTENNA–SPECIMEN FROM S. KOREA; 16. FEMALE ANTENNA (SEM), SHOWING THE SENSILLAR FORMULA; 17. FORE AND HIND WINGS.

FIGURES 18–24. Tetrabaeus americanus, FEMALE (SEM): 18. HEAD, FRONTAL VIEW; 19. BACK OF THE HEAD; 20. FORE-TIBIAL SPUR; 21. MESOSOMA,DORSAL VIEW;22. MESOSOMA,LATERAL VIEW;23. METASOMA,DORSAL VIEW;24. METASOMA,VENTRAL VIEW.

FIGURES 46–48. DISTRIBUTION OF:46. Platyscelio africanus; 47. Tetrabaeus americanus; 48. Aphanomerus rufescens (YELLOW DOTS—PAST RECORDS;RED DOTS—NEW RECORDS).