Trioxys remaudierei Starý & Rakhshani, 2017

Rakhshani, Ehsan, Pons, Xavier, Lumbierres, Belén, Havelka, Jan, Pérez Hidalgo, Nicolás, Tomanović, Željko & Starý, Petr, 2017, A new parasitoid (Hymenoptera: Braconidae: Aphidiinae) of the invasive bamboo aphids Takecallis spp. (Hemiptera: Aphididae) from Western Europe, Journal of Natural History (J. Nat. Hist.) 51 (21 - 22), pp. 1237-1248 : 1239-1242

Trioxys remaudierei Starý & Rakhshani sp. nov.

( Figure 2 (a–h))

Diagnosis

The new species is easily distinguishable from its congeners in having the ventral prongs of the abdomen fused over two-thirds of their length, then bifurcated toward the tip. The only morphologically similar species is Trioxys betulae (Marshall) , which exhibits a clearly different prong shape (and has a different host range: Symydobius Mordvilko and Clethrobius Mordvilko ). In Trioxys remaudierei sp. nov., the prong is bifurcated on the apical one-third of its length ( Figure 3 (h)) and has two or three perpendicular dorsal setae, whereas the prong in Trioxys betulae is bifurcated over half its length ( Figure 4 (c)) and has a single perpendicular dorsal seta. Trioxys remaudierei sp. nov. has a petiole that is more elongate (2.00–2.10 times as long as wide at the spiracles – Figure 2 (g)) than in Trioxys betulae (1.6–1.7 times as long as wide at the spiracles – Figure 4 (d)). Flagellomere 1 has no longitudinal placode in Trioxys remaudierei sp. nov. ( Figure 2 (c)), whereas it has three or five longitudinal placodes in Trioxys betulae ( Figure 2 (b)). The fore wing marginal setae are uniformly long in Trioxys remaudierei sp. nov. ( Figure 2 (e)), whereas the marginal setae are medium-sized and elongate in the posterior part of the fore wing in Trioxys betulae ( Figure 4 (a)).

Description of female

Head. Eye large ( Figure 2 (a)), parallel-sided in lower part, only slightly converging toward the clypeus; inter-ocular line equal to 0.31–0.32 of head width; malar space equal to 0.10– 0.11 of longitudinal eye diameter. Face and malar space sparsely hairy. Clypeus narrow, with six to eight long setae. Tentorial index (tentorio-ocular line/intertentorial line) 0.25. Maxillary palp with four palpomeres, labial palp with two palpomeres ( Figure 2 (b)). Mandible bidentate, bearing a few long setae on the outer surface. Antennae ( Figure 2 (c)) 13-segmented, filiform, prevailingly with semi-erect setae that are sub-equal to or shorter than diameter of the segments; flagellar segment 1 (=F1) 4.60–4.65 times as long as its median width, and without longitudinal placodes; F2 4.12–4.13 times as long as its median width, with two or three longitudinal placodes; F1 equal to F2.

Mesosoma. Mesonotum with notauli distinct anteriorly, with one or two rows of long setae on each side. Scutellum ( Figure 2 (d)) sub-triangular, with three long setae on each side, slightly crenulated posteriorly. Fore wing: stigma ( Figure 2 (e)) in the form of an elongated triangle with an almost straight anterior outline, 3.00–3.01 times as long as its width and 1.95–2.00 times as long as R1 vein; anterior part of r and RS vein extended downward, reaching end of R1 vein. Fore wing surface densely covered with mediumsize setae and with long marginal setae. Propodeum ( Figure 2 (f)) areolate, with large pentagonal central areola; antero-central carinae extending toward spiracles with several branches, a circular carina surrounding the spiracles on each side; postero-central carinae regular; upper part of propodeum with a row of three or four long setae on each side; lower part with one or two long setae below spiracles on each side.

Metasoma. Petiole ( Figure 2 (g)) short, 2.00–2.10 times as long as wide at the spiracles, with a pair of short setae on the postero-dorsal part, and two lateral setae below the slightly prominent spiracular tubercles; anterior part crenulated toward the center, slightly constricted between the spiracles, creating part of a shallow fovea. Ovipositor sheath ( Figure 2 (h)) elongate, 2.30–2.40 times as long as its maximal width (at base), with a single long seta and several short setae on the lateral and dorsal surfaces. Prongs ( Figure 2 (h,i)) straight and long, bifurcated on apical one-third, each having a single ovoid shape and two or three perpendicular dorsal setae, followed by a normal apical seta; the dorsal area between the bifurcation and tip bearing three long perpendicular setae, the fused part with four to six dorso-lateral setae.

Colour

Head brown, gena, face, clypeus, mouthparts yellow. Antenna light brown; scape, pedicel, F1 and F2 yellow. Mesonotum and propodeum brown, the rest of the mesosoma yellow. Legs yellow, apices of fore tarsi infuscate. Petiole and basal triangular spot on tergite 2 yellow, the rest of the metasoma brown. Ovipositor sheaths and prongs yellow to brown-yellow.

Figures

Figure 2. Trioxys remaudierei Starý & Rakhshani sp. nov. (a) Head, frontal view; (b) maxillary and labial palps; (c) antenna; (d) posterior part of mesonotum and scutellum in dorsal view; (e) fore wing; (f) propodeum; (g) metasomal terga I–IV; (h) genitalia, lateral aspect; (i) tip of prongs.

Figure 3. Mummified aphids of the species Takecallis arundinariae (Essig) parasitized by Trioxys remaudierei Starý & Rakhshani sp. nov. (a) Dorsal view; (b) posterior view indicating emergence hole.

Figure 4. Trioxys betulae (Marshall). (a) Fore wing; (b) scape, pedicel and first two flagellar segments; (c) female genitalia; (d) petiole.