Lysitermus tritoma ( Boucek , 1956)

Achterberg, Cornelis van, Skeppstedt, Fredrik & Vaeaenaenen, Simo, 2021, Revision of the Palaearctic species of Lysitermus Foerster (Hymenoptera, Braconidae, Hormiinae), ZooKeys 1040, pp. 65-89 : 73-77

Lysitermus tritoma ( Boucek, 1956) Figs 12 , 13-18 , 19-21 , 22-25 , 26-27 , 28-29

Rogadinaspis tritoma Bouček, 1956: 441.

Lysitermus tritoma ; Hedqvist, 1963: 35; Shenefelt 1975: 1155; van Achterberg 1991: 20; Gupta and Quicke 2018: 429; Mifsud et al. 2019: 54 [examined].

Paracedria suecicus Hedqvist, 1957: 219.

Lysitermus suecicus ; Hedqvist, 1963: 35 (as synonym of L. pallidus ); Shenefelt 1975: 1155; van Achterberg 1991: 20; Gupta and Quicke 2018: 429; Mifsud et al. 2019: 54 [examined]. Syn. nov.

Material.

1 ♀ (FMNH), " Finland: Ab, Parainen, Pexor , 60.26°N, 22.25°E, Malaise trap 1a, 25.vi.-6.vii.2020, Juho Paukkunen" ; 1 ♀ (CSV), same label data, but 6-19.vii.2020, Juho Paukkunen & Jonathan Scotson; 1 ♀ + 1 ♂ (RMNH), "S. Sweden: Uppland, Edsbro , Kristineholm, S15 or S20, coll. 28.i.2009, ex Inonotus radiatus on Alnus glutinosa , C. Gonzales Alonso, RMNH’11” ; 1 ♂ (RMNH), " Netherlands: UT, UTM FF 6560, Amerongen , unmanaged Quercus robur [forest], ex dead stem [in] cage 9(h), 29.v.-12.vi.2001, L. Moraal, RMNH’02” ; 1 ♀ (NMS), " France: Lot-et-Garonne, Bernac , 28.vii.[19]90, M.R. Shaw "; 1 ♀ + 2 ♂ (RMNH), " Spain, Llansa , 1986, ex Luffia lapidella , H. Hendrickx, RMNH’96”; 1 ♀ (RMNH) , " Portugal, Oeiras , 18-22.viii.1979, A. van Harten " ; 9 ♀ + 4 ♂ (RMNH), " Portugal, Cascais fort, ex Luffia lapidella , coll. 27.vii.1994, H. Hendrickx " ; 5 ♀ + 3 ♂ (RMNH), idem, but coll. 4.v.1995, ex Luffia sp .; 1 ♀ (RMNH), idem, but coll. 1.iii.1995 ; 10 ♀ + 2 ♂ (RMNH, ZJUH), idem, but Cascais (and mislabelled as from Azores), ex Luffia ferchaultella ( Psych. ), coll. 27.vii.1994, em. 21.viii.1994 ; 2 ♀ (RMNH, MTMA) " Italy: Sardinia centr., Bruncu Istiddi , 900 m, ex Luffia sp. n.?, viii.1975, E. Hartig & Gozmany" ; 1 ♀ + 1 ♂ (NMS), " Malta, Buscett , 22.xi.2006, ex larva on Luffia lapidella (Goeze, 1783) [ Psychidae ], M. Zerafa" ; 2 ♀ + 1 ♂ (NMS), " Malta: Mosta valley, larva on Eudarcia derrai ( Gaedike , 1983) [ Tineidae ], coll. 22.ii.2010, em. v.2010, M. Zerafa " ; 3 ♀ + 5 ♂ (BZL, NMS), " Romania: Siebenbürgen, Munt Apuseni ( Trascaului ), Umg. Posaga 2 km oberhalb, 600 m, ex Dahlica rakosy oder Apt. Dahlica helicoidella [ Psychidae ], em. Ende April 2005, M. Weidlich " ; 2 ♀ + 1 ♂ (BZL, NMS), " Bulgaria: Macedonia, Pirin planina - Süd, Umg. Jane Sandanski , 1220 m, el. 13.v.2000, M. Weidlich, ex Dahlica sp. [ Psychidae ]" .

Redescription.

Figured ♀ from France (NMS), length of body 1.6 mm and of fore wing 1.4 mm.

Head. Antenna 1.1 × as long as fore wing, with 15 segments, rather widened apically (Fig. 12 ), scapus oblique apically, length of third segment 1.1 × fourth segment; third, fourth and penultimate segments 5.0, 4.5, and 3.1 × their width, respectively; face largely smooth, with long erect setae and 1.7 × wider than high; clypeus smooth, upper half distinctly convex and ventral half depressed; head in dorsal view 1.8 × broader than long medially, eye 1.4 × longer than temple dorsally, strongly and roundly narrowed posteriorly (Fig. 18 ); vertex smooth and shiny, including area near stemmaticum (Fig. 18 ); occipital carina moderately strong and in front of it indistinctly micro-crenulate; POL: diameter of posterior ocellus: OOL = 2:2:3; eye in lateral view 1.6 × as high as wide, temple distinctly broadening ventrally, smooth and width of eye 1.6 × minimum width of temple laterally (Fig. 12 ); malar space 0.4 × as long as height of eye and 1.5 × as long as basal width of mandible; frons smooth and shiny.

Mesosoma. Mesosoma 1.5 × as long as high in lateral view; mesoscutum granulate and with 2 rather short carinulae and no medio-posterior groove (Fig. 14 ); notauli shallow, distinctly developed anteriorly and posterior half obsolescent, largely smooth and anteriorly connected to lateral irregular carina; scutellar sulcus with 1 carina; scutellum smooth and shiny, convex (Fig. 14 ); propodeum shiny, largely smooth between carinae and with large areola, its median carina approx. as long as anterior side of areola (Fig. 14); side of pronotum rugose-crenulate and with some granulate sculpture; mesopleuron largely smooth and convex (Fig. 12 ); precoxal sulcus rather deep and only in anterior half present, with few crenulae anteriorly; metapleuron largely smooth and with long setae; mesosternal sulcus deep, narrow and smooth. Wings. Fore wing: pterostigma elongate triangular and 3.5 × longer than wide (Fig. 13 ), r issued from its middle and slightly longer than width of pterostigma; 2-SR completely absent (Fig. 13 ); 3-SR 1.5 × longer than r; SR1 straight and reaching tip of wing; m-cu rather short (Fig. 13 ); subdiscal cell distally closed, CU1b close to m-cu and CU1a at same level as 2-CU1 (Fig. 13 ). Legs. Hind coxa largely smooth; length of femur, tibia and basitarsus of hind leg 5.0, 9.2, and 5.2 × their width, respectively; hind tarsus hardly compressed.

Metasoma. Length of first tergite 0.6 × its apical width, its dorsal surface evenly convex, surface longitudinally striate and with additional granulate sculpture between striae, its dorsal carinae lamelliform and medially interconnected; medial length of second tergite 0.9 × its basal width, and 1.4 × as long as third tergite; second and third tergites longitudinally striate and with distinct secondary granulate sculpture; second transverse suture coarsely crenulate and nearly straight (Fig. 15 ); third tergite antero-laterally without minute tooth-shaped protuberance and distinctly narrowed posteriorly (Figs 15 , 16 ), with distinct smooth and shiny apical rim (Fig. 15 ); apical lamella of third metasomal tergite moderately protruding laterally (Fig. 12 ), concave and wide in dorsal view, with approx. 8 carinae (Fig. 16 ); setose part of ovipositor sheath 0.21 × as long as fore wing and 0.6 × as long as hind tibia, slightly widened apically (Fig. 12 ).

Colour. Dark brown; third tergite dark brown, contrasting with largely yellowish brown second tergite (Figs 15 , 16 ); first tergite yellowish brown; antenna (basal segments yellowish), pterostigma (but basal fifth yellow) and veins M+CU1 apically, 1-CU1, 1-M, and veins of apical half of fore wing dark brown (Fig. 13 ); palpi and tarsi pale yellowish; remainder of legs yellowish brown; wing membrane infuscate, but band below base of pterostigma and marginal cell partly, subhyaline (Fig. 13 ).

Variations. Antenna with 14-17 segments; length of body 1.5-1.9 mm, and of fore wing 1.3-1.5 mm; length of ovipositor sheath 0.21-0.26 × as long as fore wing; vein 2-SR of fore wing varies from completely absent (Figs 13 , 19 ), complete (Fig. 29 ) to small unsclerotised trace (Fig. 45 ); notauli complete to posterior third obsolescent; scutellar sulcus with 1-3 carinae; precoxal sulcus smooth or with few crenulae; metapleuron largely smooth or with some rugulae medially; median carina of propodeum approx. as long as anterior side of areola or much shorter; second metasomal tergite 1.3-1.5 × longer than second tergite; lamella of third tergite hardly serrate (Fig. 12 ), with 8-16 carinae; colour of body is very variable: southern specimens are brownish yellow with only third tergite dark brown and northern specimens are largely dark brown (except first and second tergites, but in both Finnish specimens also darkened; Figs 27 - 29 ), sometimes hind coxa, femur and tibia largely brown or dark brown (Fig. 29 ).

Male. Very similar to female, but metasoma slenderer (Fig. 20 ); antenna with 16 or 17 segments; length of body 1.4-1.6 mm, and of fore wing 1.3 mm; head dark brown dorsally; linear medio-posterior depression of mesoscutum absent or slightly impressed; third tergite dark brown and contrasting with yellowish second tergite (Fig. 20 ), striate and/or granulate and its lamella hardly serrate (Figs 19-21 , 45 ); pterostigma dark brown basally.

Biology.

Reared from lepidopterous case-bearing larvae belonging to Psychidae ( Luffia ferchaultella (Stephens, 1850); L. lapidella (Goeze, 1783); L. sp.; Dahlica sp.) and Tineidae ( Eudarcia derrai (Gaedike, 1983); Mifsud et al. 2019). It has been reared from Inonotus radiatus bracket fungi on Alnus glutinosa ( L. ) ( Jonsell et al. 2016), most likely from host cases hiding in the fungi.

Distribution.

*Bulgaria, Czech Rep., *Finland, *France, Italy (Sardinia), Malta, *Netherlands, Poland, *Portugal (mainland), *Romania, *Spain (mainland), Sweden.

Notes.

The medio-longitudinal carina of the propodeum is very variable in length, from about as long as oblique anterior side of propodeal areola to much shorter and the second metasomal suture varies from distinctly sinuate (typical L. tritoma ; Figs 24 , 25 ) to straight (typical L. suecicus ; Figs 15 , 20 , 22 ). After more reared specimens became available, intermediates of both characters have been found, and there are no grounds to separate any longer the two species, as has been proposed by van Achterberg (1991).

The holotype of L. suecicus (NRS) is incorrectly figured in the original description. For instance, the second tergite is not twice as long as the third tergite but 1.5 × (Fig. 22 ), the ovipositor sheath is not widened but subparallel, and the pterostigma is not robust but rather slender (Fig. 22 ).

Figures

Figure 12. Lysitermus tritoma (Boucek), ♀, France, habitus lateral. Photograph: R. Soethof.

Figures 13 - 18. Lysitermus tritoma (Boucek), ♀, France 13 wings 14 mesosoma dorsal 15 propodeum and metasoma dorsal 16 second and third metasomal tergites dorsal 17 head anterior 18 head postero-dorsal. Photographs: R. Soethof.

Figures 19 - 21. Lysitermus tritoma (Boucek), ♂, Malta 19 habitus dorso-lateral 20 propodeum and metasoma dorsal 21 second and third metasomal tergites dorsal. Photographs: R. Soethof.

Figures 22 - 25. Lysitermus tritoma (Boucek), ♀, 22 holotype L. suecicus, 23 - 25 types of L. tritoma 22 habitus dorsal 23 metasoma lateral 24, 25 detail third tergite dorsal. 22 from Forshage et al. (2016) and 23 - 25 from Boucek (1956).

Figures 26 - 27. 26 Lysitermus pallidus Foerster, ♀, Sweden (freshly emerged specimen), habitus lateral 27 L. tritoma (Boucek), dark ♀, Finland, metasoma dorsal. Photographs: F. Skeppstedt (26) and P. Malinen (27).

Figures 28 - 29. Lysitermus tritoma (Boucek), dark ♀, Finland 28 body dorsal 29 habitus lateral. Photograph: P. Malinen.

Figures 45 - 47. Lysitermus talitzkii (Tobias), ♂ holotype, but 47 of ♂ paratype 45 habitus lateral 46, 47 metasoma dorsal. Photographs: K. Samartsev.