Aleiodes praetor (Reinhard, 1863)

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 : 102-107

Aleiodes praetor (Reinhard, 1863) Figs 285, 286-287, 288-301

Rogas praetor Reinhard, 1863: 264; Shenefelt 1975: 1244; Tobias 1986: 78 (transl.: 128).

Aleiodes praetor ; Papp 1991: 73; Belokobylskij et al. 2003: 398.

Neorhogas luteus Szépligeti, 1906: 606; Shenefelt 1975: 1205; Papp 1977: 115 (as synonym of Aleiodes praetor ); 1991: 73; 2004: 215 (lectotype designation); Chen and He 1997: 37.

Type material.

Holotype of Aleiodes praetor ♀ (MNHN) from France ("Mout. [= Moutiers, Savoie]", “Moutiers”, “Muséum Paris, 1867, Coll. O. Sichel", " Rogas praetor Rhd.") and lectotype of Neorhogas luteus ♂ (MTMA) from Serbia examined.

Additional material.

Austria, Belgium, British Isles (England: V.C.s 5, 11, 16, 17, 19, 20, 21, 22, 24, 30, 31, 34, 38, 62, 64), *Bulgaria, Croatia, Finland, France, Germany, Hungary, Netherlands (GE: Heerde; LI: Stein, Epen, Tegelen; NH: Naardermeer; UT: Bilthoven, Leersum; ZH: Melissant, Oostkapelle), Serbia, Spain, Sweden, Switzerland. Specimens in NMS, MNHN, BMNH, CMIM, OUM, RMNH, FMNH, NRSM, MTMA, S. Dodd collection, P. McMullen collection, WAE, UWIM.

Molecular data.

MRS067 (England KM067256/KU682219, CO1 + EU854334, 28S), MRS654 (Bulgaria HQ551265/KU682244, CO1).

Biology.

Aleiodes praetor is a univoltine parasitoid of at least some arboreal Sphingidae , and overwinters in the host mummy. Reared specimens seen were from Lathoe populi (Linnaeus) (1 CMIM; C. Morley), Mimas tiliae (Linnaeus) (2 OUM, 1 NMS, 1 BMNH, 1 RMNH; J.C. Fraser, J. Koorneef, R.A. Softly). In Britain the flight period is from late June through August. A series of males was reared in culture in both Lathoe populi and Mimas tiliae parented by a virgin female from Mimas tiliae . The female was often seen hanging from a leaf edge by only a few of her legs (Fig. 285). Most ovipositions, into late first instar and more particularly second instar hosts, occurred in a rearing cage overnight and were unobserved; however two of these remarkable occasions were witnessed (into late first instar Lathoe populi ). The host, which rests and feeds from the under surface of the leaf, was approached and repeatedly touched with the outstretched extreme tips of the antennae, causing the host to twitch more or less violently from side to side. It is noteworthy that the apical segment of the antenna in this species has a well-pronounced nipple-like tip (Fig. 297). When this reaction wore out, the parasitoid suddenly jumped on the host and rapidly inserted her ovipositor, with the metasoma scarcely curled; she then immediately straightened her body and released her footing completely so that she hung from the host with only her ovipositor touching it, and all legs completely free of any support. After 30 seconds she jerked free, and took flight as she fell from the host, which was apparently not paralysed to any extent although it was quiescent during oviposition. The extraordinary oviposition behaviour is clearly facilitated by the unusual flange and teeth at the apex of the ovipositor (Fig. 295), and may be completely constraining: otherwise suitable hosts on the floor of containers (i.e. lacking a drop) were consistently just walked over or otherwise ignored. The lack of paralysis ensures that the host maintains its footing, without risk that it would fall and be unable to rediscover its food source. The mummy appears to be highly adapted for a lengthy persistence in crevices in tree bark. It is very hard, matt, and predominantly light greyish brown in colour but with darker transverse variegation and sometimes small dark grey dorsal patches (Fig. 287). The parasitoid occupies abdominal segments (4 –)5– 8 which become thinly lined with silk and weakly arched. This structure is strongly stuck down ventrally at about the fourth abdominal segment, with the anterior part of the host becoming physically detached at an oblique angle by the action of the parasitoid larva. In captivity the stricken hosts sought refuge in paper tissues at the base of the rearing boxes, where mummies were made glued firmly in surface folds, and, despite Morley’s (1916) finding a mummy on a Populus leaf, it is clear that the penultimate instar host larva is normally induced to descend and find a crevice before perishing; indeed, a partly grown Mimas tiliae larva which was collected on the bark of a Tilia tree was mummified within a few hours (R.A. Softly, personal communication). Before the widespread use of UV lights by lepidopterists Aleiodes praetor was rarely collected in Britain; now, however, specimens turn up quite regularly in light traps.

Diagnosis.

Large yellowish brown species with antennal segments of female 67-77 and of male 62-75; OOL 0.3 × diameter of posterior ocellus; lateral carina of scutellum strong and lunula rather narrow; marginal cell of hind wing narrowed near basal 0.6 and slightly widened apically (Fig. 289); inner apex of hind tibia with weak and indistinct comb; tarsal claws yellowish setose; ovipositor sheath largely glabrous (except apically and ventrally; Fig. 301); ovipositor with small teeth ventrally and with wide dorsal flange (Fig. 295); length of fore wing 8-10 mm; parasitoid of Sphingidae .

Description.

Redescribed ♀ (RMNH) from Naardermeer, length of fore wing 8.7 mm, of body 8.8 mm.

Head. Antennal segments of ♀ 72, with many tyloids and apex of subbasal segments oblique (Fig. 296), length of antenna 1.2 × fore wing, its subapical segments distinctly longer than wide and apical segment with long spine (Fig. 297); frons narrow, rather flat and largely micro-granulate; OOL 0.3 × diameter of posterior ocellus and micro-sculptured; vertex flat, micro-sculptured and shiny; clypeus convex, micro-granulate and near lower level of eyes; ventral margin of clypeus not differentiated (Fig. 299); width of hypoclypeal depression 0.5 × minimum width of face (Fig. 298); face micro-sculptured and partly transversely rugulose; length of eye 3.2 × temple in dorsal view (Fig. 300); occiput behind stemmaticum superficially sculptured; length of malar space 0.2 × length of eye in lateral view; occipital carina strong, but medio-dorsally absent; eyes distinctly protruding (Figs 298-300).

Mesosoma. Mesoscutal lobes densely punctate, micro-sculptured and shiny; prosternum rather large and distinctly concave; prepectal carina complete, distinct; precoxal area of mesopleuron with some striae medially; mesopleuron above precoxal area strongly shiny, punctate medio-posteriorly and remainder smooth (Fig. 290); metapleuron punctate dorsally and rugose ventrally; scutellar sulcus wide, deep and with 7 carinae; scutellum flat, densely punctate, with striae medio-posteriorly and lateral carina largely present and lunula narrow; propodeum convex, dorsal face about as long as posterior face, densely rugose, tuberculate protruding latero-dorsally (Fig. 290), propodeal spiracle large and median carina of propodeum complete and regular.

Wings. Fore wing: r 0.6 × 3-SR (Fig. 288); 1-CU1 nearly horizontal, slender, 0.2 × 2-CU1; r-m 0.4 × 3-SR and not pigmented; second submarginal cell rather long (Fig. 288); cu-a inclivous, curved posteriorly; 1-M straight posteriorly. Hind wing: marginal cell subparallel-sided basally, constricted near basal 0.7 and its apical width nearly equal to width at level of hamuli (Fig. 289); 2-SC+R short; m-cu absent; M+CU:1-M = 33:16; 1r-m 1.1 × as long as 1-M.

Legs. Tarsal claws yellowish setose; hind coxa punctate and micro-sculptured dorso-basally and remainder largely smooth and punctulate; hind trochantellus ventrally twice as long as wide; length of fore femur, hind femur and basitarsus 6.3, 4.2 and 7.8 × their width, respectively (Figs 292-293); length of inner hind spur 0.35 × hind basitarsus; inner apex of hind tibia with indistinct weak comb.

Metasoma. First tergite as long as wide apically (Fig. 291); first and second tergites densely and coarsely longitudinally rugose, with distinct median carina, reduced near apex of second tergite; medio-basal area of second tergite absent; length of second tergite 0.7 × its basal width; second suture deep and distinctly crenulate; third tergite 0.9 × as long as second tergite, anterior half largely densely and finely punctate and remainder of metasoma largely smooth and depressed; fourth and apical half of third tergite without sharp lateral crease; ovipositor sheath largely glabrous (except apically and ventrally; Fig. 301); ovipositor with small teeth ventrally and with wide dorsal flange (Fig. 295).

Colour. Yellowish brown; antenna (but scapus brownish basally), stemmaticum, apical third of hind tibia (except spurs) and hind tarsus largely, black; base of hind tibia pale yellowish; pterostigma and veins brownish yellow; wing membrane largely subhyaline, but basally slightly pigmented and near veins 1-SR and 1-M slightly infuscate.

Variation. Antennal segments of European ♀ 67(2), 68(7), 69(7), 70(7), 71(3), 72(4), 73(4); of ♂ 62(3), 63(5), 64(5), 65(5), 66(1), 67(1); males have fifth–seventh tergites moderately setose; vein m-cu of fore wing sometimes slightly curved and gradually merging into 3-CU1; precoxal sulcus entirely smooth or with some striae; scapus and pedicellus partly yellowish brown or entirely black.

Notes.

European males have approximately four fewer antennal segments than females. Antenna of possibly conspecific Chinese and Japanese females consists of 70-77 segments and of males 62-75 segments and they have the pterostigma darker compared to the veins below it.