Aleiodes leptofemur, van Achterberg, Cornelis & Shaw, Mark R., 2016

van Achterberg, Cornelis & Shaw, Mark R., 2016, Revision of the western Palaearctic species of Aleiodes Wesmael (Hymenoptera, Braconidae, Rogadinae). Part 1: Introduction, key to species groups, outlying distinctive species, and revisionary notes on some further species, ZooKeys 639, pp. 1-164 : 75-82

Aleiodes leptofemur sp. n. Figs 203-204, 205-214

Aleiodes? nigriceps ; Shaw 1983: 319, 321.

Aleiodes borealis ; Shaw 1994: 134, 136, 137.

Aleiodes borealis ; Papp and Rezbanyai-Reser 1996: 73, 96.

Aleiodes borealis ; Belokobylskij et al. 2003: 398.

Aleiodes nigriceps auctt. p.p. (not Wesmael 1838).

Type material.

Holotype, ♀ (NMS, Edinburgh), "[England:] Norfolk, Santon, ex Stilbia anomala on Deschampsia flexuosa , 18.xii.[20]01, mum.?ii.[20]02, em. 12.v.[20]02, G. M. Haggett", "MRS Aleiodes DNA 154". Paratypes (475 ♀, 412 ♂) from England (West Cornwall, East Cornwall, South Devon, North Devon, Isle of Wight, North Somerset, North Wilts, South Wilts, Dorset, North Hants, South Hants, West Sussex, East Sussex, East Kent, West Kent, Surrey, South Essex, Herts, Middlesex, Berks, Oxford, Bucks, West Suffolk, East Norfolk, West Norfolk, Cambridge, Bedford, Hunts, Northampton, East Gloucester, West Gloucester, Warwick, Stafford, Leicester, Derby, Chester, South Lancaster, Mid-west York, North-west York, Westmorland), Scotland (Dumfries, Ayr, Lanark, Berwick, Haddington, Edinburgh, Linlithgow, Fife, Stirling, West Perth, East Perth, Elgin, Easterness, Westerness, Dunbarton, Kintyre, West Ross), Wales (Glamorgan, Merioneth, Caernarvon, Monmouth, Pembroke, Anglesey), Isle of Man, Guernsey, Jersey, Andorra (St. Julia), Austria ( Niederösterreich: Raglitz; Poysdorf; Hainburg; Oberösterreich: Linz, Kirchschlag; Sensengebirge Bärenriedlau), Belgium (Mt. St. Pierre), Bulgaria (Rodopi: Galabovo), Cyprus (Yermasoyia Riv.; Yeroskipon; Cherkes; Limasol; Paramytha), Czech Republic (Sumava, 1000-1300m; Moravia: Mikulov), France (Orsay; Hautes-Alpes: Briançon), Finland (Kainuu: Kuhmo), Germany (Bonn: Rheinhöhenweg im Kottenforst; Schleswig-Holstein: Lübeck; Niedersachsen: Berkhof; Gottingen: Hann-Munden; Bonn; Rheinland, Köln-Flittard; Bavaria: Wiesen/Spessart; Lower Saxony: Harzburg; Mullingen; Alfeld; Oberhaverbeck; Hürth-Fischenich; Ahlem; Saxony: Zöbigker; Baden-Württemberg: Heidel /Jagdl; Goslar, Astfeld), Gibraltar (Botanical Garden), Greece (Lakonia, Parnon Oros, 1700 m; id., Taygetos, 1000-1200 m; Thessalia: Mt Olympos; Pisadia; Kozani). Hungary (Budapest: Budaliget; Budakeszi, Hársbokorhegy; Pécs, Tettye), Ireland (WI: Ballinclea; SK: Caragh Lake; DU: Phoenix Park; Carlow, Antrim), Italy (Tuscany: Gorgona Isl.; Sicily: Catania; Mt. Etna, Milo Fornazzo, 800 m; Bolzano, Sarntal; 1250 m; Südtirol: Ahrntal; Trentino: Riva s. Garda; Trentino: Tremalzo), Netherlands (DR: Wijster; Borger, FL: Lelystad (Oostvaardersplassen & Jagersbos), GE: Gortel; Ede; Epe; Heerde; Nunspeet; Tongeren, NB: Baarle-Nassau; Eindhoven; Geertruidenberg; Hoogerheide; Nijmegen, Berg en Dal; Vierlingsbeek; Etten-Leur; Hilvarenbeek; Rijen; Bergen op Zoom; Oss; Raamdonksveer; Tilburg (Kaaistoep), LI: Arcen; Geulle; Lemelerberg; Neercanne; Wrakelberg; Grubbenvorst; St. Pietersberg; Vilt; Wolder, NH: Weesp; Texel, Oudeschild, UT: Linschoten, ZH: Meijendel; Oostvoorne; Ouddorp; Lexmond; Melissant; Nieuwkoopse Plassen; Noordwijk; Rotterdam; Voorschoten; Waarder, FR: Ried; Terschelling, ZE: Haamstede; Westenschouwen), Norway (Oppland, Lom-Lia), Slovakia (B. Karpaty-Jaktar, Drietoma), Spain (Teruel, Tramacastilla; Navarra, Alsasua, 600 m; Mallorca, Porto Cristo; Zaragoza: Juslibol), Sweden ( Skåne: Järahusen; Ystad; Böste; Spraggehusen; Ö. Väringe; Spukke; Härjedalen: Tänndalen; Duvberget; Halland: Åsa Närsbokrok), and Switzerland (GR: Sent Surains, Val Gronda, 1500 m). Paratypes in NMS, AAC, BMNH, BZL, M. Riedel collection, RMNH, H. Schnee collection, SYKE, MSC, ZJUH, MCZ and ZSSM.

Molecular data.

MRS154 (England KU682229, CO1), MRS156 (England JF962813, CO1), MRS157 (England KU682230, CO1), MRS515 (Netherlands KU682260, CO1).

Biology.

A parasitoid of a wide range of low feeding noctuid larvae, as listed below. Overwinters as a small larva in the host, which is killed before it is in its final instar. Mummy (Fig. 204) largely dark brown (summer generations paler) and slender, usually formed in a prominent position at least in spring. Specimens (in NMS unless indicated) reared from wild-collected Noctuidae identified as Abrostola triplasia (Linnaeus) (1; J.L. Gregory), Ammoconia caecimacula (Denis & Schiffermüller) (4:1; J. Connell/Austria), Autographa gamma (Linneaus) (2; G.E. King/Spain, E. Haeselbarth/Germany; 1 (RMNH), G. Peters/Germany),? Cerastis rubricosa (Denis & Schiffermüller) (1; J.L. Gregory), Cucullia chamomillae (Denis & Schiffermüller) (2; A.A. Allen [1 is AAC]),? Diarsia rubi (Vieweg) (1; T.H. Ford), Dicestra trifolii (Hufnagel) (1; G.M. Haggett), Euplexia lucipara (Linnaeus) (6:1; P. Baker), Lacanobia oleracea (Linnaeus) (2:1; P. Baker), Melanchra pisi (Linnaeus) (5; P. Baker, A. Lord, M.R. Shaw), Mythimna ferrago (Fabricius) (1; J. L. Gregory),? Mythimna impura ( Hübner) (3:1; M. R. Hall),? Mythimna littoralis (Curtis) (1; F.D. Bennett), Noctua comes Hübner (14; J. Connell[?], D. Hackett[?], G.M. Haggett, E. Haeselbarth, R. Hinz, R.A. Softly), Noctua fimbriata (Schreber) (2; G.M. Haggett, R.A. Softly), Noctua interjecta Hübner (2; M.R. Hall, G.M. Haggett), Noctua janthina (Denis & Schiffermüller) (1; G.M. Haggett), Noctua orbona (Hufnagel) (3; G.M. Haggett), Noctua pronuba (Linnaeus) (5 [2 are BMNH]; R.A. Softly), Orthosia gracilis (Denis & Schiffermüller) (1; M.R. Shaw), Paradiarsia glareosa (Esper) (1; G.M. Haggett), Phlogophora meticulosa (Linnaeus) (10; M.R. Shaw, R.A. Softly, J. Voogd), Shargacucullia verbasci (Linnaeus) (24 [5 are OUM, 1 is AAC]; A.A. Allen, F.C. Woodforde, M.R. Shaw), Standfussiana lucernea (Linnaeus) (1; R.F. Logan), Stilbia anomala (Haworth) (4; G.M. Haggett), Xestia agathina (Duponchel) (12 [6 are ZSSM, 2 are AAC]; A.A. Allen, E. Bauer, A. Dobson, M.R. Shaw), Xestia baja (Denis & Schiffermüller) (1; J.L. Gregory), Xestia castanea (Esper) (8 [5 are ZSSM]; E. Bauer, K.P. Bland[?], M.R. Shaw), Xestia xanthographa (Denis & Schiffermüller) (31 [1 is ZSSM, 1 is RMNH]; E. Bauer, M.R. Britten, J. Connell, G.M. Haggett, M.R. Hall, N. Hall, R. Hinz, M.R. Shaw, R.A. Softly), and unidentified noctuids (81 [14 are BMNH], mostly collected as mummies). Specimens in NMS reared in culture experiments are included in the type material (but not in the above host list), and these experimental results (using females from the overwinter generation to parasitize summer hosts) are as follows: Diarsia rubi 1:16\16\\7+4 [several others were retarded but died]; Dicestra trifolii 5:28\28\\24+4; Lacanobia oleracea 6:28\22\\0+16 [several others were retarded but died]; Melanchra persicariae (Linnaeus) 4:22\13[several others pricked and paralysed without oviposition]\\0+13; Orthosia cerasi (Fabricius) 7:55\6\\5+1; Orthosia gothica (Linneaus) 6:40\1\\0+1; Orthosia gracilis 8:27\16\\14+2; Orthosia incerta (Hufnagel) 6:23\4\\2+1; Phlogophora meticulosa 9:49\44\\29+14: Shargacucullia verbasci 1:1\1\\1+0. In Britain adult flight times peak around May, July–August and October. However, in common with most Aleiodes , the adults are very long-lived and can be found in most months (but we have no British records from January to March). Both sexes come feely to light, but it is also active by day. The males tend to court non-conspecific females (at least of some species) with as much - though unsuccessful - vigour as with conspecifics. All host records are from Noctuidae feeding on low plants, but within that group this species has an unusually broad host range. Many (but not all) of the overwintering hosts, such as Noctua and Xestia species (parasitized from September to November), feed on Poaceae and grow slowly during mild periods in the winter, with mummification by the parasitoid in the host’s 3rd or 4th instar sometimes as early as February, but more often during March or April. The resulting adults again parasitize low-feeding noctuids, with a similarly broad range of hosts, but mostly on plants other than Poaceae . Adults of both sexes are often swept from trees and bushes (especially in late summer and autumn) but they are probably merely feeding on honeydew rather than seeking hosts: although some Noctua and Xestia species that feed through the winter on grasses do sometimes oviposit on tree leaves, with the resulting larvae feeding thereon until (easily!) displaced, their falling to the field layer usually happens in the first instar (MRS, personal observation) when they are probably still too small to be easily parasitized by Aleiodes leptofemur . It is rather remarkable that the host larvae, especially of the overwintering generation, regularly (perhaps invariably) climb out of their normal living space, to be mummified fully exposed high on stems of various kinds (very often on dead grass seed heads), on tree trunks, fence posts etc. Related common species such as Aleiodes nigriceps , Aleiodes pictus and Aleiodes similis (Curtis, 1834) [the latter to be treated in a subsequent part of this revision], which (at least overwinter) parasitize ecologically similar and closely related - or in many cases the same - noctuid species, do not cause their hosts to do this, but instead the hosts parasitized by these species seek concealment before mummification. Consequently, mummies of this group found exposed in nature are almost invariably those of Aleiodes leptofemur . It is an obvious suggestion that this helps the parasitoid to avoid idiobiont parasitism (pseudohyperparasitism) in the dangerous field layer, including by virtue of faster development to the relative safety of the adult stage (the spring-forming mummies are very dark and presumably absorb insolation energy well), but it does leave open the question why the other (related, and similarly plurivoltine) species mentioned above have not adopted the same habit.

Diagnosis.

Length of fore femur 6.4-8.0 × its maximum width (Fig. 209) and hind femur parallel-sided (Fig. 208); mesosternum usually black(ish); face with some weak transverse rugae dorsally; OOL 1.5 × diameter of posterior ocellus; temple roundly narrowed (Fig. 214); scapus ventrally and usually basal half of antenna (dark) brown, rarely yellowish; hind femur slender, basally largely yellowish and frequently infuscate subapically, but remaining nearly always paler than ventral side of scapus; if rarely hind femur is distinctly infuscate (Fig. 208) then often also hind coxa (at least basally) and base of hind tibia infuscate (Fig. 203); face usually black or dark brown medially and near eyes yellowish brown; antennal segments of ♂ 35-40, usually 36-38, less than of ♀, which has usually 37-39 segments; pterostigma tending to be dark brown medially (Fig. 205). Similar to Aleiodes borealis (Thomson, 1892) and to species of the Aleiodes pictus aggregate. They differ by having the length of the fore femur 5.4 –6.4(– 7.3) × its maximum width and the hind femur more or less weakly swollen; if more than 6.4 × then the face without transverse rugae dorsally, the hind femur comparatively wide basally, the mesosternum yellowish or the temple comparatively wide, or the scapus ventrally and the basal half of the antenna yellowish brown; if the scapus is dark brown or blackish then the scapus is similarly coloured as the hind femur subapically; colour of the hind femur variable, usually dark brown or blackish subapically; face usually completely black or rarely yellowish; antennal segments of male 37-45, averages about one segment more than of female, which has 36-45 segments (32-34 in Aleiodes borealis , of which we have not seen a male with complete antenna); pterostigma is variable, but often yellowish medially; clypeus distinctly transverse and less depressed ventrally, and hind femur rather micro-sculptured. Some dark males of Aleiodes similis are very like pale males of Aleiodes leptofemur and in extreme cases scarcely separable. The new species shares with the East Palaearctic Aleiodes angustatus (Papp, 1971) the elongate and paralle-sided fore and hind femora. Aleiodes angustatus has the body entirely yellowish brown, the ocelli larger (POL slightly less than the diameter of the posterior ocellus and OOL about 1.2 times diameter of ocellus), the antenna of ♀ with 47-49 (♂: 46-49) segments, the second metasomal tergite nearly parallel-sided, the precoxal sulcus witrh distinct rugae and the pterostigma yellow.

Description.

Holotype, ♀, length of fore wing 4.5 mm, of body 4.4 mm.

Head. Antennal segments 39, length of antenna 1.1 × fore wing, its subapical segments about 1.8 × as long as wide (Fig. 211) and basal segments comparatively wide (Fig. 210); frons granulate-coriaceous, with satin sheen; OOL 1.5 × diameter of posterior ocellus and coriaceous; vertex granulate-coriaceous, with satin sheen; clypeus distinctly convex (Fig. 213), coriaceous; ventral margin of clypeus rounded and depressed (Fig. 212); width of hypoclypeal depression 0.4 × minimum width of face and face coriaceous, dorsally somewhat rugulose (Fig. 212); length of eye 2.5 × temple in dorsal view and temple gradually roundly narrowed behind eye (Fig. 214); occiput behind stemmaticum granulate-coriaceous, occipital carina interrupted by somewhat more than width of ocellus (Fig. 214); clypeus partly above lower level of eyes (Fig. 212); length of malar space 0.4 × length of eye in lateral view; eyes moderately protruding (Figs 212-214).

Mesosoma. Mesoscutal lobes finely coriaceous, with satin sheen, medio-posteriorly with a few rugulae; notauli complete and narrow, largely smooth and posteriorly reduced; prepectal carina narrow lamelliform, reaching anterior border; precoxal area of mesopleuron granulate-coriaceous, mesopleuron with superficially granulate and shiny speculum and rugose dorso-anteriorly (Fig. 206); metapleuron granulate-coriaceous, matt and posteriorly not tuberculate; mesosternal sulcus narrow and rather deep, shallow medio-posteriorly and no carina; mesosternum angulate posteriorly; scutellum elongate, slightly convex, granulate-coriaceous and laterally largely without carina; propodeum rather flat dorsally, not tuberculate latero-posteriorly, and coriaceous with median carina complete.

Wings. Fore wing: r 0.3 × 3-SR (Fig. 205); 1-CU1 horizontal, 0.4 × as long as 2-CU1; r-m 0.6 × 2-SR, and 0.35 × 3-SR; second submarginal cell comparatively large (Fig. 205); cu-a weakly oblique, not parallel with CU1b, straight; 1-M nearly straight posteriorly. Hind wing: apically marginal cell nearly twice as wide as its minimum width; 2-SC+R short and longitudinal; m-cu short and not pigmented (Fig. 205).

Legs. Tarsal claws setose; hind coxa finely coriaceous, largely matt; hind trochantellus 2.4 × longer than wide; length of fore and hind femora 6.9 and 6.9 × their width, respectively (Figs 208-209); inner apex of hind tibia without comb; length of inner hind spur 0.3 × hind basitarsus.

Metasoma. First tergite 1.1 × as long as wide posteriorly and latero-posteriorly narrowly lamelliform, moderately convex and flattened posteriorly, dorsope medium-sized (Fig. 207); first and second tergites densely and longitudinally rugulose (Fig. 207), with distinct median carina; medio-basal area of second tergite absent; second suture narrow and finely crenulate; third tergite coriaceous and remainder of metasoma largely smooth and shiny; fourth and apical half of third tergite without sharp lateral crease; ovipositor sheath (except dorsally) moderately setose.

Colour. Black; antenna dark brown; palpi largely brown; tegulae, malar space ventrally and triangular patch on second tergite pale yellowish (Fig. 207); inner orbita as dark as face centrally; outer orbita posteriorly and dorsally, malar space dorsally and mesoscutum medio-posteriorly brownish yellow (Fig. 213); mesopleuron with ventral brownish yellow stripe (Fig. 206); hind coxa largely, apical half of hind femur, base of hind tibia and tarsi rather fuzzy dark brown (Figs 203, 208) and remainder of legs yellowish brown; veins and pterostigma (except yellow basal 0.3 and slightly apex) dark brown; border between dark and pale part of pterostigma rather sharp, contrasting with each other (Fig. 205); wing membrane subhyaline.

Variation. Length of fore wing 4.5-5.0 mm; antennal segments of ♀ 35(3), 36(16), 37(79), 38(98), 39(70), 40(20), 41(1), 42(1), of ♂ 35(22), 36(64), 37(89), 38(60), 39(17), 40(4), 41(1)); mesosoma largely black to largely orange brown; medial length of second tergite 0.8-0.9 × its basal width; OOL of male slightly longer than diameter of posterior ocellus and apical half of antenna dark brown; mesopleuron medially and propodeum rugose or superficially rugulose. Specimens of the summer generation(s) are usually overall paler than those from the overwinter generation. The face usually dark centrally with the inner orbits paler but sometimes face completely black (as in the type, from the overwinter generation), less often completely orange or darkened only near clypeus (males more likely than females to exhibit these extremes). Extent of orange markings on mesoscutum extremely variable, but almost always distinct; metasoma only rarely wholly black or dark brown. Colour of pterostigma very variable, sometimes pale greyish and only faintly darker near posterior margin.

The broad host range, which has (at least in part) been experimentally verified, may contribute to the variability of this species. We have seen a large number of summer-generation female specimens from S. Europe (Portugal, Greece, Turkey and most notably a long series from South Bulgaria from Rodopi in BZL) that consistently differ in colour from summer specimens from Britain in the combination of a slightly darker pterostigma, uniformly pale legs, and the metasomal tergites posterior to the central pale area tending to be reddish brown rather than blackish, and they are also slightly smaller. Because of its relative uniformity in contrast to the variability of what we otherwise regard as Aleiodes leptofemur , it seem possible that this material represents a different species and we have not included it in the type series.

Etymology.

This common and widely distributed species is named after its slender femora ( “leptos” = Greek for “thin”).

Distribution.

*Andorra, *Austria, *Belgium, *British Isles (England, Wales, Isle of Man, Scotland, Ireland, Guernsey, Jersey), *Bulgaria, *Cyprus, *Czech Republic, *France, *Finland, *Germany, *Gibraltar (British territory), *Greece, *Hungary, *Italy, *Netherlands, *Norway, *Slovakia, *Spain, *Sweden, *Switzerland. The southern European countries are included provisionally (see above under variation).

Notes.

Males have on average about one fewer antennal segments than females. Both authors have left determination labels for this species incorrectly as Aleiodes borealis (Thomson) on a large number of specimens in many collections (up until about 2006 for CvA; until 2007 for MRS), which are now impossible to correct.