Tricholabus THOMSON

A. M, 2011, Illustrated key to the genera of the subtribe Amblytelina of Palaearctic (Hymenoptera, Ichneumonidae, Ichneumoninae, Ichneumonini), Linzer biologische Beiträge 43 (1), pp. 597-711 : 629-631

2. Tricholabus THOMSON

Tricholabus THOMSON 1894 - Opusc. Ent., 19: 2103, 2113.

Type species: Tricholabus femoralis THOMSON.

Tricholabus: HEINRICH 1961 - Can. Ent., Suppl. 23: 387-388.

Tricholabus: HEINRICH 1977 - Ichn. Florida and Neigb. States, 9: 93-94.

Tricholabus: RASNITSYN 1981 - Opr. Faun. SSSR 3 (3): 564, 623-624.

D i s t r i b u t i o n: Holarctic and Neotropical Region.

I n t r o d u c t i o n:

Genus Tricholabus THOMSON occupies uncertain taxonomic position. Such characters as rather convex scutellum, convex horizontal part of propodeum, amblypygous abdomen and practically not sculptured postpetiolus are making it closer to Platylabini . Sloped propodeum with parallel lateral longitudinal carina and carina metapleuralis is characteristic to representatives of Protichneumonini and to genus Lymantrichneumon HEINRICH (Ichneumonina) . A. RASNITSYN (1981) refers it conventionally to Amblytelina subtribe on the base of the morphology of males and females hypopygium. At the same time, smooth unstriated postpetiolus, deep gastrocoeli with developed thyridia and slight sclerotization of sternites of abdomen contradict to this concept. Moreover, habitually, with exception of amblypygous abdomen and apical bands on apex of abdomen, the genus is similar to Ulesta CAMERON (Ichneumonina) , particularly to Tricholabus coreanus (Uchida) stat. nov. (= Tricholabus strigatorius coreanus (Uchida)) species from Russian Far East with strong constrictions between front tergites of abdomen of females.

M o r p h o l o g y:

F l a g e l l u m: Bristle-shaped, slender, strongly attenuated to apex, only just widened beyond middle and in females only just flattened. Flagellum of females and males with white semiannulus. Flagellum of males ribbed ventrally practically from the base, without tyloides.

H e a d: Contour of head from front strongly roundly narrowed downwards; temples behind eyes from above roundly narrowed in a hind half. Occipital carina from above deeply and roundly impressed, merge with hypostomal carina on mandible base (in contrast to other genera of the subtribe); mandibles rather short and broad with two teeth, upper considerably longer than lover one; malar space sharply separated from the lateral fields of face; clypeus with straight front margin and thickened, oblique lateral margins, practically not separated from the middle field of face by impression.

T h o r a x: Mesonotum moderately convex, longer than width; notauli only just marked at base; subalarum high, moderately thick, not sharpened; sternauli only just marked at base; scutellum rather high elevated above postscutellum, convex, not carinated laterally and gradually sloped to postscutellum. Hind margin of metanotum with projections. Propodeum in profile roundly convex; coxal carina absent, costulae absent (European species) or present; basal area long; area superomedia hexagonal, from middle narrowed and rounded anteriad, elongated; areae dentiparae at apices without teeth with external carina almost parallel to carina metapleuralis; spiracles not great, narrow.

L e g s: Slender, long, hind coxae of females without scopa; claws of all the legs, smooth, thin, gradually curved.

W i n g s: Areolet pentagonal with broad base; radius slightly sinuous; nervulus postfurcal; membrane of wing hyaline.

A b d o m e n:Offemalesamblypygous, narrow. Middle field of postpetiolus with rare sparse, punctures, slightly elevated and not carinated. Gastrocoeli large, very deep, almost not oblique, with equal width and length; thyridia sharp, equal or wider than interval between them. Sternites 2-4 of abdomen strongly unsclerotized with sharp longitudinal fold (plica); hypopygium of females from below long, triangular with acute apex and membranous hind margin; hypopygium of males with extended apex and characteristic knoll-shaped swelling on it.

C o l o r a t i o n: Body of European species black with red 1-3rd tergites of abdomen (in East Palaearctic to entirely black) and white apical bunds on tergites 4-7. Legs black or red.

S i z e: 10-12 mm.

B i o l o g y a n d e c o l o g y:

H o s t s: For T. strigatorius (GRAV.) the 3 species of Noctuidae are known as the hosts – Heliothis viriplaca HUFN., H. dipsacea L. and Callistege mil CL. (TOWNES et all 1965; RASNITSYN 1981).

S p e c i e s c o m p o s i t i o n a n d a b u n d a n c e: The genus is presented in region of researches by only one species – T. strigatorius (GRAV.) . By bundance in the collections, the genus is on 4 th place among Amblytelina and on 24 th place among genera of Ichneumoninae St. in the region. (32 individuals / 1 species of genus).

B i o t o p i c a l d i s t r i b u t i o n: Genus prefers open ecosystems (meadows and personal plots) – 75 % from collected individuals. From forest ecosystems, it is registered in pine, oak and alder forests.

S e a s o n a l a c t i v i t y a n d h i b e r n a t i o n: Activity ofbothmalesand females of T. strigatorius is observed since June till September. Males have two peaks of activity in June and September accordingly, that allows to suppose presence of two generations. Hibernating females of Tricholabus are not found during of all period of investigations.