Aleiodes testaceus (Telenga, 1941)

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 : 114-120

Aleiodes testaceus (Telenga, 1941) Figs 341-342, 343-352

Heterogamus testaceus Telenga, 1941: 134 ; Shenefelt 1975: 1202; Tobias 1986: 85 (transl.: 142; lectotype designation); Papp 1991: 115 (examined).

Aleiodes testaceus Bergamesco et al. 1995: 5 ; Papp and Rezbanyai-Reser 1996: 83, 87, 1997: 116; Fortier and Shaw 1999: 221; van Achterberg and Aguiar 2009: 793-794.

Type material.

Lectotype ♀ (ZISP) from southern Russia (Astrakhanskaya Oblast) examined.

Additional material.

*Austria, British Isles (*England: V.C.s 2, 3, 5, 17, 21, 22, 23, 28, 29, 31, 32, 38, 39, 57, 58, 63; *Wales: V.C.s 48, 52; *Ireland: H5, H30 and Co. Cork), Bulgaria, *Cyprus, France (*mainland and *Corsica), Greece (mainland), Italy, Morocco, *Netherlands (NB: Tilburg (Kaaistoep)), Portugal (Madeira), Spain (mainland, *Mallorca and *Canary Islands (Gomera; Gran Canaria; Tenerife)). Specimens in NMS, BMNH, RMNH, CNC, BZL, OUM, ZISP, ZSSM, CMIM, UWIM, AAC.

Molecular data.

MRS057 (Corsica JF973344, CO1) MRS084 (England JF962864, CO1), MRS086 (England KU682223, CO1), MRS103 (Corsica KU682226, CO1), MRS106 (Corsica KU682227, CO1), MRS261 (France JF962863, CO1).

Biology.

This is a plurivoltine parasitoid of Eupithecia ( Geometridae : Larentiinae ) and close relatives feeding on flowers, overwintering as an adult. Specimens in NMS reared from wild collected larvae identified as Eupithecia dodoneata Guenee (10; T.H. Ford/France, M.R. Shaw/France), Eupithecia sp. (6), Chloroclystis v-ata (Haworth) (9; G.M. Haggett, M.R. Shaw), Gymnoscelis rufifasciata (Haworth) (2; G.M. Haggett, M.R. Shaw). Hosts were always associated with flowers, especially of trees ( Quercus ) and shrubby plants ( Ligustrum , Clematis ), but including field layer plants ( Solidago , Torilis ). Adults always emerge in the year of formation of the mummy, and females of this species overwinter as adults. In addition to a torpid specimen having been beaten from conifers in late December and another taken in early March (both M.W.R. de Vere Graham, southern England), this has been confirmed experimentally. However, in captivity the females tend to become active and require food above about 4 °C, indicating that the species is best adapted to areas where the winter is relatively short, as in southern Europe. Dissection of 5 (out of 51) female specimens collected by fogging Quercus canopy in mid September (southern England, N.E. Stork) revealed neither mature nor developing eggs, only moderately extensive fat bodies. As the species had been virtually absent from other fortnightly samples fogged from the same trees, it seems that they were feeding, perhaps on honeydew, prior to overwintering elsewhere. Because males are found late in the summer as well as early, it appears to be a plurivoltine species; however, it is unclear whether the autumnal specimens lacking mature eggs had resorbed them or refrained from developing them. Light trapped specimens tend to be female, but this is probably just a consequence of the much longer life span of the female sex, and in reared series the sex ratio is more equal. The light brown, banana-shaped, apically attenuated and short-lived mummy is interesting in not being stuck down at the thoracic area; instead (at least when forming from relatively elongate and fully exposed Eupithecia larvae such as those of Eupithecia dodoneata ) it projects outwards at an angle similar to that normally adopted by the host at rest. None the less, a ventral opening is made by the parasitoid larva in the host’s thoracic region at the time of mummification, through which a small quantity of fluid is expelled and quickly dries.

Diagnosis.

Antennal segments of female 30-35 (of male 34-37); third antennal segment rather slender (Fig. 348); OOL about equal to diameter of posterior ocellus (Fig. 351); area in front of anterior ocellus with a minute smooth tubercle; ventral margin of clypeus thick (Fig. 350); maximum width of hypoclypeal depression 0.30-0.35 × minimum width of face; length of malar space of female 0.3-0.4 × height of eye in lateral view (Fig. 350); occipital carina very widely effaced dorsally (Fig. 351); vein r of fore wing 0.7-0.9 × vein 3-SR; vein 1-SR of fore wing rather long; vein 1r-m of hind wing distinctly shorter than vein 1-M (Fig. 343); marginal cell of hind wing somewhat widened apically; inner hind tibial spur 0.25-0.30 × as long as hind basitarsus; tarsal claws setose; pterostigma, inner side of basal half of hind tibia, head and mesosoma largely yellowish, but mesopleuron dorsally and propodeum usually more or less dark brown; third metasomal tergite with more or less developed diverging striae laterally

Description.

Redescribed ♀ (RMNH) from Garde Freinet (France: Var), length of fore wing 3.3 mm, of body 3.7 mm.

Head. Antennal segments 32, antenna as long as fore wing, its subbasal and subapical segments about 2.4 and 1.7 × as long as wide, respectively; frons mainly granulate and flat; OOL equal to diameter of posterior ocellus and very finely granulate as vertex, with satin sheen; clypeus weakly convex, medium-sized and granulate; ventral margin of clypeus thick and depressed (Fig. 350); width of hypoclypeal depression 0.3 × minimum width of face (Fig. 349) and face granulate and with medium-sized setae; length of eye 3.2 × temple in dorsal view and temple gradually narrowed behind eye; occiput behind stemmaticum very finely granulate and occipital carina complete ventrally and widely interrupted dorsally; clypeus near lower level of eyes (Fig. 349); length of malar space 0.35 × height of eye in lateral view; eyes rather protruding (Figs 349-351).

Mesosoma. Mesoscutal lobes finely granulate, matt and medio-posteriorly rugose; anterior half of notauli narrow, shallow and smooth and posterior half obsolescent; prepectal carina narrow lamelliform medio-ventrally, not reaching anterior border of mesopleuron; precoxal area of mesopleuron finely rugulose medially (Fig. 344); remainder of mesopleuron above precoxal area nearly smooth or superficially shiny granulate, but dorsally finely rugose; medially metapleuron distinctly granulate and with some rugae, rather shiny; mesosternal sulcus narrow and shallow; mesosternum rounded posteriorly; scutellum nearly flat, densely granulate and laterally non-carinate; propodeum convex, and rugulose-granulate, median carina complete, without tubercles.

Wings. Fore wing: r nearly as long as 3-SR (Fig. 343); 1-CU1 horizontal, 0.5 × as long as 2-CU1; r-m 0.8 × 2-SR, and 0.7 × 3-SR; second submarginal cell short (Fig. 343); vein M+CU1 of fore wing apically at level of vein 2-CU1; vein 1-SR of fore wing rather long and nearly linear with vein 1-M (Fig. 343); cu-a short and vertical, first subdiscal cell narrow (Fig. 343); 1-M nearly straight posteriorly. Hind wing: apical half of marginal cell slightly widened apically; 2-SC+R short and longitudinal; m-cu present as unpigmented fold; M+CU:1-M = 7:5; 1r-m moderately oblique and 0.7 × as long as 1-M.

Legs. Tarsal claws yellowish setose; hind coxa granulate and with satin sheen; hind trochantellus 2.2 × longer ventrally than wide; length of fore and hind femora 6.4 and 4.7 × their width, respectively (Figs 346-347); 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, convex and latero-posteriorly narrowly lamelliform; first–second tergites and basal 0.6 of third tergite finely longitudinally rugose, interspaces granulate and with median carina (Fig. 345); remainder of metasoma superficially micro-sculptured; medio-basal area of second tergite absent; second suture medium-sized, rather shallow and crenulate; third tergite 0.8 × as long as second tergite; fourth tergite without sharp lateral crease; remainder of metasoma partly retracted; ovipositor sheath truncate apically and moderately setose.

Colour. Brownish yellow; stemmaticum, patch on outer side of scapus and pedicellus, apical third of antenna, pronotum dorsally, mesopleuron dorsally, metanotum, metapleuron dorsally, propodeum largely and veins around 1-M of fore wing dark brown; remainder of veins brown or yellowish; palpi, tegulae and pterostigma pale yellowish; wing membrane subhyaline; first tergite somewhat infuscate basally; ovipositor sheath black.

Variation. Antennal segments of ♀ 30(1), 31(9), 32(24), 33(78), 34(30), 35(6); of ♂ 34(7), 35(16), 36(18), 37(9); side of pronotum and metasoma of both sexes sometimes largely dark brown or brown except ivory patch of second and third tergites and yellowish brown apex of metasoma.

Notes.

This species is distinctive and (with the wide use of UV light traps by lepidopterists) proving to be rather common in southern England, but it seems to have been very rarely collected and generally overlooked as a British species until quite recently. However, it has probably been present for a long time; a British specimen in the Dale collection (OUM) is dated 1892. In The Netherlands known since 2006 but only from one locality in the southern province of Noord-Brabant. On average the males have 2-3 antennal segments more than females.

The name " testaceus " (or the invalid emendation " testaceator " by Thunberg (1822)) has been used for 3 different taxa or groups of taxa in the genera Rogas / Rhogas , Aleiodes or Heterogamus ( Braconidae : Rogadinae ). Most taxa included in the past in Rogas / Rhogas are now included in the genus Aleiodes Wesmael, 1838 s. l. ( Yu et al. 2012) as well as some taxa formerly included in Heterogamus Wesmael, 1838 (including Heterogamus testaceus Telenga, 1941 ).

The oldest name is Ichneumon testaceus Fabricius, 1798 , not Gmelin, 1790. As a junior homonym Ichneumon testaceus Fabricius is unavailable, and the oldest available name for this taxon is Rogas luteus Nees, 1834 (see van Achterberg 1982). In 1822 Thunberg emended the Fabrician name to " testaceator ", but this emendation is invalid. The senior homonym Ichneumon testaceus Gmelin is a synonym of Monoblastus brachyacanthus (Gmelin, 1790) and belongs to the Ichneumonidae : Tryphoninae (Yu & Horstmann 1997) .

Second is " Aleiodes testaceus " of Spinola (1808) of which the original combination is Bracon testaceus . It has so often been considered to be a valid taxon that it is included as such in Taxapad ( Yu et al. 2012). However, in the supposed description by Spinola (1808), the author refers to Ichneumon testaceus Fabricius, 1798 , and it is, therefore, not a valid description of a new taxon. Nomenclaturally it is the same as Rogas luteus Nees, 1834 (see above), but subsequent authors have incorrectly interpreted it as another (or other) species. Rogas luteus Nees is a valid name and refers to the type species of the genus Rogas Nees, 1819 , and its (unjustified) emendation Rhogas Agassiz, 1849. " Aleiodes testaceus (Spinola) " of authors usually refers to one or another of several brownish yellow ( “testaceous”) species of Aleiodes , most often the taxon which we consider to be correctly named as Aleiodes similis (Curtis, 1834) , or taxa included in Taxapad under the species-aggregate of Aleiodes gastritor (Thunberg, 1822) s. l. ( Yu et al. 2012). According to Art. 11.5 of the ICZN Code ( 1999), to be available a name must be used as valid for a taxon when proposed, unless it was first published as a junior synonym and subsequently made available under the provisions of Art. 11.6.1. The status of a previously unavailable name is not changed by its mere citation as a valid taxon (Art. 11.5.2) and Bracon testaceus was not described by Spinola as a new taxon. A name could become available according to Art. 11.10, if it was deliberately employed for a misidentified type species, but this does not apply to the Aleiodes testaceus of Spinola. In principle, to maintain prevailing usage of a misinterpreted name, the case could be brought to the Commission for a ruling, but in our opinion there are no good reasons to do this because the intention of Spinola (1808) is unambiguous, the name has been used for several taxa, and it is not an iconic name that should be preserved because of many unambiguous published citations outside of the field of taxonomy.

Finally, Heterogamus testaceus Telenga, 1941 , was (correctly in our view) included in the genus Aleiodes by several authors, including Shenefelt (1975) and Bergamesco et al. (1995). Thus Aleiodes testaceus (Telenga) could be confused, nomenclaturally, with " Aleiodes testaceus (Spinola) " of authors (belonging mainly to the Aleiodes gastritor -aggregate or other taxa of what we refer to in this paper as the Aleiodes circumscriptus -group). The two are only distantly related according to Fortier and Shaw (1999), a conclusion with which we concur (including from unpublished molecular data; Quicke et al. in prep.). Included among the purposes of this paper is to clarify the differences between these taxa and to suppress the incorrect usage of the name " Aleiodes testaceus (Spinola) " of authors not ( Telenga 1941), as for example by Quicke (2015).