Aleiodes dissector (Nees, 1834)

van Achterberg, Cornelis, Shaw, Mark R. & Quicke, Donald L. J., 2020, Revision of the western Palaearctic species of Aleiodes Wesmael (Hymenoptera, Braconidae, Rogadinae). Part 2: Revision of the A. apicalis group, ZooKeys 919, pp. 1-259 : 1

Aleiodes dissector (Nees, 1834) Figs 234-239 , 240-242 , 243-255 , 256-263

Rogas dissector Nees, 1834: 208; Shenefelt 1975: 1225-1226; Papp 1977a: 110.

Rogas (Rogas) dissector ; Tobias 1976: 81, 1986: 75 (transl.: 121).

Aleiodes (Neorhogas) dissector ; Papp, 1985a: 145, 1987b: 35, 1991a: 74, 1991d: 5, 1999: 550; Belokobylskij, 1996: 9; Riedel et al., 2002: 106.

Aleiodes (Chelonorhogas) dissector ; Belokobylskij 2000: 34; Ku et al. 2001: 234, 235.

Aleiodes dissector ; Fortier and Shaw 1999: 230; Belokobylskij et al. 2003: 398; Zaldívar-Riverón et al. 2004: 234, 2008: 392; Papp 2005: 176; Belokobylskij et al. 2008: 136-137.

Phylax aestivalis Snellen van Vollenhoven, 1858: 282; Shenefelt, 1975: 1226 (as synonym of A. dissector ); van Achterberg 1992: 363 (id.); Papp 2005: 176 (id.) [examined].

Type material.

Holotype of A. aestivalis , ♀ (RMNH), "[Netherlands], Haag [= near The Hague], 6 [= June], v.Voll.". According to the original description the ♂ holotype of R. dissector from Germany should be in the Gravenhorst collection (Museum of Natural History, University of Wrocław, Wrocław), but so far it has not been found.

Additional material.

Austria, British Isles (England: V.C.s 15, 17, 20, 22, 23, 24, 30, 31, 34, 37, 58; Scotland: V.C.s 73, 88, 89, 95, 96, 97, 107), Croatia, Czech Republic, Finland, France, Germany, Greece, Hungary, Montenegro, Italy, Netherlands (FL: Lelystad, GE: Barneveld, OV: Raalte (Heino), ZH: Wassenaar), Norway, Russia, Serbia, Slovakia, Switzerland, Ukraine, [Armenia]. Specimens in ZJUH, BZL, CNC, IKC, MRC, MSC, MSNV, MTMA, NMS, OUM, RMNH, SDEI, UNS, UWIM, ZSSM.

Molecular data.

MRS007 (Turkey), MRS025 (Turkey), MRS145 (UK), MRS146 (UK).

Biology.

Univoltine, collected in May and June in deciduous scrub and woodland. In Britain it is widespread but particularly common in birch-dominated woodland in upland Scotland. Reared from the noctuids Orthosia incerta (Hufnagel) (17, M.R. Shaw), O. gothioca (Linnaeus) (1, J.L. Yela) and Orthosia sp. (3), overwintering in the concealed mummy. An additional specimen, lacking a mummy but labelled as reared doubtfully from the sesiid Paranthrene tabaniformis (Rottemburg) (RMNH), which normally feeds under Populus bark at ground level or below, can be discounted as a probable substrate rearing in which the mummy of the true host was overlooked. Parasitised host larvae in their penultimate instar leave their feeding sites and enter the soil or other site of moderate concealment (including below loose bark), where they prepare a chamber as though to pupate. At this time the parasitoid larva within the strongly retarded host (Fig. 234 ) is around half its final length, and the host lies quiescent for approx. a week until the parasitoid has completed its feeding (Fig. 235 ). During mummification (Figs 236 , 237 ) the caudal end of the host recurves ventrally as the host’s body becomes weakly retracted. A ventral opening at the head end is made, but the head (as with the caudal segments) is usually tucked downwards rather than becoming raised, and so the resulting expelled fluid (Fig. 237 ) usually dries without the mummy becoming stuck down. The eventual outcome is a rather distinctive (Fig. 238 ) elongate and curved dark brown structure with a paler and weakly raised lateral keel. The parasitoid’s pupation chamber occupies ca 2nd-8th abdominal segments of the host, which are moderately strongly lined with silk (Fig. 239 ).

The moderately large hypoclypeal opening and protruding sharp-rimmed clypeus of A. dissector is seen in some other species (e.g., A. modestus (Reinhard), treated in part 1 of this work) whose hosts also pupate in shallow soil. In culture experiments A. dissector was found to prefer hosts in the early to middle part of the 3rd instar, although late 2nd instar host were often also acceptable. Oviposition into suitable hosts was rapid (1-2 seconds) and accomplished with a single insertion of the ovipositor, following only brief antennation and no use of the legs. There was no clear temporary paralysis. Experimental rearings from O. incerta (6:107\85\\75+10) and O. gothica (6:61\49\\34+15) were comparable (given that some insertions of less than a full second might have been scored as ovipositions incorrectly; and furthermore that some failures to oviposit into these hosts might be ascribed to temporary egg depletion, as the protocol of normally ceasing to offer hosts to a particular female after four apparent ovipositions on the day had not been developed until after the experiments were undertaken), and clearly demonstrated the suitability of both species as hosts. In contrast, no parasitoids developed (and indeed possibly no ovipositions occurred) in the other species of Orthosia tested, which were all found to be clearly outside the host range: O. cerasi (Fabricius) (3:32\?3\\0+3); O. cruda (Denis & Schiffermüller) (2:12\0\\-); O. munda (Denis & Schiffermüller) (3:10\0\\-); O. gracilis (Denis & Schiffermüller) (2:11\?1\\0+1). Of these four, only O. gracilis is not fully arboreal. There is no adverse venom effect on host development.

Diagnosis.

Maximum width of hypoclypeal depression 0.6-0.7 × minimum width of face (Fig. 251 ); OOL of ♀ 0.6-0.7 × diameter of posterior ocellus (Fig. 252 ) and sparsely punctate; ventral margin of anterior part of clypeus comparatively sharp and more or less protruding outwards (Fig. 253 ); length of malar space 0.2 × length of eye in lateral view (Fig. 253 ); head transverse in dorsal view and eye 1.5-2.0 × as long as temple in dorsal view (Fig. 252 ); lobes of mesoscutum punctulate, with interspaces smooth to superficially micro-sculptured; precoxal area completely smooth or nearly so; vein 1-CU1 of fore wing 0.2-0.3 × vein 2-CU1 and horizontal (Fig. 243 ); hind tarsal claws with conspicuous dark brown pecten close to apical tooth (Fig. 250 ); 1st tergite rounded antero-laterally and 1.0-1.1 × as long as wide apically; basal half of metasoma black and weakly sculptured; 3rd tergite smooth; head black; palpi yellowish; basal half of hind tibia pale yellowish, but in some males almost uniformly dark; 4th-6th tergites of males depressed medially and conspicuously setose (Fig. 258 ).

Description.

Redescribed ♀ (RMNH) from Austria (Burgenland, Winden am See). Length of fore wing 8.5 mm, of body 9.0 mm.

Head. Antennal segments of ♀ 60, antenna as long as fore wing, its subapical segments rather slender, slightly longer than wide; frons largely smooth; OOL 0.7 × diameter of posterior ocellus, sparsely punctate, shiny and with deep groove near posterior ocellus (Fig. 252 ); vertex sparsely punctate, rather shiny; clypeus coarsely punctate; ventral margin of clypeus rather thin and forward protruding (Fig. 253 ); width of hypoclypeal depression 0.7 × minimum width of face (Fig. 251 ); length of eye 1.5 × temple in dorsal view (Fig. 252 ); vertex behind stemmaticum superficially rugose-punctate; clypeus near lower level of eyes; length of malar space 0.2 × length of eye in lateral view.

Mesosoma. Mesoscutal lobes punctulate with interspaces superficially micro-sculptured and shiny; precoxal area of mesopleuron smooth except some punctulation, mesopleuron punctulate anteriorly and posteriorly; metapleuron densely punctate; metanotum with nearly complete median carina; scutellum flat (but with rugulose depression medio-posteriorly), remainder punctulate and with weak lateral carinae; propodeum evenly convex and coarsely rugose, and medio-longitudinal carina absent posteriorly.

Wings. Fore wing: r 0.4 × 3-SR; 1-CU1 horizontal, 0.3 × 2-CU1; r-m 0.3 × 3-SR; 2nd submarginal cell medium-sized (Fig. 243 ); cu-a inclivous, straight; 1-M straight posteriorly; 1-SR medium-sized; surroundings of M+CU1, 1-M and 1-CU1 largely setose. Hind wing: marginal cell rather narrow basally, apical half gradually widened, its apical width 3.1 × width at level of hamuli (Fig. 244 ); 2-SC+R subquadrate; m-cu absent; M+CU:1-M = 35:33; 1r-m 0.7 × 1-M.

Legs. Tarsal claws with conspicuous and robust dark brown pecten (Fig. 250 ); hind coxa distinctly punctate and with some oblique striae postero-dorsally; hind trochantellus robust; length of hind femur and basitarsus 3.8 and 5.3 × their width, respectively; length of inner hind spur 0.45 × hind basitarsus.

Metasoma. First tergite flattened, basally narrowed, as long as wide apically; 1st and 2nd tergites with medio-longitudinal carina and largely finely punctate-rugose, but posterior quarter of 2nd tergite irregularly rugose and no median carina; medio-basal area of 2nd tergite wide and triangular, distinct (Fig. 247 ); 2nd suture rather deep and micro-sculptured; 3rd and subsequent tergites largely smooth; apical half of 3rd and 4th tergites without sharp lateral crease; ovipositor sheath wide, with long and medium-sized setae and apically truncate (Fig. 241 ).

Colour. Black; apical half of hind tibia and hind tarsus blackish; basal half of hind tibia pale yellowish; remainder of legs, palpi and tegulae yellowish brown; most veins and pterostigma dark brown; wing membrane slightly yellowish basally and remainder slightly infuscate.

Variation. Interspaces between punctulation of mesoscutum smooth to superficially micro-sculptured; medio-longitudinal carina of propodeum complete or absent posteriorly; 3rd metasomal tergite largely finely sculptured (except posteriorly) to largely smooth; mesopleuron black or with brownish longitudinal stripe; hind tibia usually ivory or pale yellowish basally. Antennal segments: ♀ 51(2), 55(2), 56(7), 57(4), 58(7), 59(12), 60(14), 61(18), 62(6), 63(4); ♂ 51(1), 53(2), 54(2), 55(4), 56(8), 57(29), 58(29), 59(27), 60(15), 61(4), 62(4), 63(2), 64(2). Females have on average ca one to two more antennal segments than males. Males are very similar but hind femur more or less blackish and, in some males, hind tibia almost uniformly dark, OOL approx. as long as diameter of posterior ocellus (Fig. 257 ) and apical tergites type 3-4 with fringe long and strong (Figs 258 , 260 ).

Distribution.

*Armenia, *Austria, British Isles (England, Scotland), Croatia, Czech Republic, Finland, France, Germany, *Greece, Hungary, *Montenegro, *Italy, Netherlands, Norway, Russia, *Serbia, Switzerland, Ukraine.

Figures

Figures 234 - 239. Aleiodes dissector (Nees), U. K., Scotland (in culture) parasitising Orthosia incerta (Hufnagel) 234 pre-mummy, removed from its hideaway, with unparasitised control from the same egg batch (below) 235 pre-mummy 236 early mummification 237 mummy with ventral ooze 238 three fully hard mummies 239 emerged mummy, cut open to expose silken lining.

Figures 240 - 242. Aleiodes dissector (Nees), ♀, Switzerland, Tessin, but 242 from Scotland (culture) 240 habitus lateral 241 ovipositor sheath lateral 242 mummy of Orthosia incerta (Hufnagel).

Figures 243 - 255. Aleiodes dissector (Nees), ♀, Switzerland, Tessin 243 fore wing 244 hind wing 245 mesosoma lateral 246 mesosoma dorsal 247 propodeum and 1 st - 4 th metasomal tergites dorsal 248 fore femur lateral 249 hind femur lateral 250 outer hind tarsal claw 251 head anterior 252 head dorsal 253 head lateral 254 base of antenna 255 apex of antenna.

Figures 256 - 263. Aleiodes dissector (Nees), ♂, Austria, Kaernten 256 habitus lateral 257 head dorsal 258 3 rd- 7 th tergites lateral 259 mesosoma dorsal 260 1 st- 6 th metasomal tergites dorsal 261 fore femur lateral 262 head anterior 263 hind femur lateral.