Xorides xylotrechi Varga, Maqbool & Wachkoo, 2022

Maqbool, Iqra, Varga, Oleksandr, Maqbool, Amir, Wachkoo, Aijaz Ahmad, Banu, A. Najitha & Rather, Sumi Ulah, 2022, Xorides xylotrechi sp. n. (Hymenoptera: Ichneumonidae: Xoridinae) parasitizing Xylotrechus stebbingi (Gahan, 1906) (Coleoptera: Cerambycidae) in India, Zootaxa 5150 (1), pp. 121-128 : 122-127

Xorides xylotrechi Varga, Maqbool & Wachkoo , sp. n.

( Figs 1–3 )

urn:lsid:zoobank.org:act:4350BACB-3A31-42D6-9DBD-CF02DA5A5B22

Material examined. Holotype: ♀, INDIA: Jammu and Kashmir, Budgam: Chadoora , 33° 56 31.5 N 74° 48 03.5 E, 1608 m a.s.l., reared 31.x.2019, leg. Amir Maqbool. Paratypes: 3 ♂, the same locality, 05.x.2019. Other material. 3♀, the same locality and date as paratypes, 2♀, the same locality, 06.v.2020, leg. Iqra Maqbool (specimens with removed ovipositors for morphological study) (deposited in: CUZM —A_Maqbool00001 to A_Maqbool00009).

Diagnosis. Xorides xylotrechi sp. n. is characterized by the combination of the following characters: body generally black with yellow marks ( Fig. 1A, B ); antenna simple, not subapically sharply angled at a single joint ( Fig. 1C ); vertex smooth and shiny, sparsely punctate; occipital carina complete ( Fig. 1F ); epicnemial carina present ( Fig. 1H ); fore and middle trochantelli without apical tooth; fore wing with vein 1cu-a distad of vein M&RS by about 0.2× of its length ( Fig. 1I ); propodeum with distinct carinae and strong tooth-like projections ( Fig. 1H ); first metasomal tergite 1.5–1.7× as long as apical width, rugulo-punctate, with distinct lateroapical grooves, and weak latero-median carinae present on basal 0.3 of the tergite (absent in males) ( Fig. 1J ); ovipositor about 1.4–1.6× length of hind tibia; male antenna with long erect setae ( Fig. 2C ).

Xorides xylotrechi sp. n. is similar to Palaearctic X. praecatorius (Fabricius, 1793) and Afrotropical X. konduensis (Benoit, 1952) , but differs in having stronger sculptured body and indistinct latero-median carinae on first tergite (carinae are distinct and reaching the apex of the tergite in X. praecatorius and X. konduensis ). In addition, Xorides xylotrechi sp. n. lacking red body marks on head and mesosoma ( X. praecatorius has abundant yellow body colouration only in combination with largely red body and X. konduensis has red head marks, but yellow colouration reduced). The newly described species also resembles Oriental species, X. asperus Wang & Gupta, 1995 and X. centromaculatus , but differs by the propodeal carination (area basalis and area superomedia separated in Xorides xylotrechi sp. n., while X. centromaculatus and X. asperus — confluent), absence of yellow mark on mesoscutum (present in X. asperus and X. centromaculatus ) and different colour pattern of legs. Xorides xylotrechi sp. n. also has dark clypeus comparing to yellow in X. praecatorius , X. asperus and X. centromaculatus . In addition, male of Xorides xylotrechi sp. n. differs from X. praecatorius and X. centromaculatus by the long setae on antenna (males of X. konduensis and X. asperus unknown).

Description. Female. Holotype ( Fig. 1 ). Body length approximately 11 mm. Fore wing 8 mm.

Head ( Fig. 1C–F ) smooth and densely pubescent. Antenna subapically not sharply angled at a single joint, with 20 flagellomeres, flagellomeres 17–19 with 5 long sensillae. Face about 0.45× as long as wide, sparsely punctate and weakly rugulose; malar space 0.5× the basal width of mandible, with subocular sulcus distinct; clypeus 0.5× as long as wide, sharply angled on basal 0.25, rugulose, but weaker sculptured (weakly rugulose on shiny surface) on apical 0.75, with rounded apical margin. Temples long and parallel behind eyes, gently rounded (dorsal view), wrinkled in lower part (genae). Frons smooth, with short carina-like projection between antennal sockets; length of the ocellar-ocular distance 1.1× maximum diameter of lateral ocellus. Vertex sparsely punctate; occipital carina complete.

Mesosoma ( Fig. 1G, H ) strongly sculptured and densely pubescent. Propleuron sparsely punctate. Pronotum with epomia distinct and strong, smooth before epomia and densely punctate after. Mesoscutum densely punctate, rugulose centrally, with strong foveolate notauli; scuto-scutellar groove wide, with central longitudinal carina; scutellum densely punctate. Mesopleuron sparsely punctate; epicnemial carina present, almost reaching anterior margin of mesopleuron; sternaulus present, but weak proximally. Metapleuron rugulose, pleural and submetapleural carinae present. Propodeum rugulose, with longitudinal and transverse carinae present and strong; apophyses strong; spiracles elongate.

Legs relatively stout; hind femur 3.6× as long as wide, hind coxa smooth and shiny; fore and middle tibiae swollen, with V-shaped median ventral groove; trochantelli without apical tooth; tarsal claws simple.

Wings ( Fig. 1I ). Fore wing with vein 2 rs-m short, about 0.7× the distance between 2 rs-m and 2 m-cu; vein 1cu-a distad of M & RS by about 0.2× of its length; hind wing with distance between distal abscissa of Cu and M about longer than vein cu-a.

Metasoma ( Fig. 1J ) strongly sculptured and densely pubescent. First tergite 1.6× as long as apical width, rugulo-punctate, with distinct lateroapical grooves; latero-median carinae present, but weak on basal 0.4 of the tergite; dorso-lateral carinae reaching 0.75 of the tergite, but weak. Second tergite rugulo-punctate, 0.8× as long as apical width, with two large (but weak) basolateral swellings delimited by the deep grooves. Third tergite densely punctate, swellings weaker; the remaining tergites weakly aciculate. Ovipositor about 1.5× as long as hind tibia, with the apical teeth; ovipositor sheaths densely pubescent.

Colour. Body generally black with ivory marks. Head black except inner and outer eye orbits largely (interrupted on vertex), and flagellomeres 9–14 ivory; clypeus brownish. Mesosoma black except large marks of pronotum, mesopleuron, scutellum and postscutellum, propodeum apically ivory. Metasoma generally black with apical ivory bands on tergites 2–8; first tergite with two large lateroapical marks and small central mark on apical margin, partly orange in basal half. Legs generally orange with black and yellow marks; all femora and hind coxae orange; all trochanters and trochantelli marked with black; fore and middle coxae black with ivory marks; fore and middle tibiae orange-brown with yellow lines, hind tibiae orange-brown, yellow subbasally; tarsi brownish. Ovipositor sheaths black. Pterostigma and veins brown.

Male ( Fig. 2 ). Body length 9.2–9.6 mm. It generally resembles female, but differs in the following characters: antenna with 25 flagellomeres and long setae ( Fig. 2C ); propodeum smoother, but with numerous irregular wrinkles ( Fig. 2F, G ); metasoma stronger sculptured and more slender ( Fig. 2H ), first tergite 2.0× as long as apical width. Males are generally darker with reduced yellow colouration present as lines on face and frons, spots on genae, pronotum, mesopleuron, scutellum and second metasomal tergite.

Variability. Body length 9.6–11.2 mm. Fore wing length 8–9.4 mm. Size of central mark on apical margin of 1 st tergite varying from small, separated from two large lateroapical marks to a wide mark touching the lateroapical marks. Second metasomal tergite partly orange in basal half but orange coloration reduced to a small basomedian mark in two specimens.

Etymology. The new species is named after the host of the genus Xylotrechus (Chervolat, 1852) .

Distribution. Currently known only from North of India.

Biology. The newly described species was observed as solitary ectoparasitoid emerging individually from each host. No mating of opposite sexes was observed. Females constantly tap the antennae on the bark to locate the host ( Fig. 3A ). The subdistal antennal flagellomeres possess hammers (antennal hammers) or pegs-like structures that help in detecting the host. Once the host larva was located, the female balanced its ovipositor on the surface of the bark and started drilling ( Fig. 3B ). The wasp removed and reinserted the ovipositor 3–4 times before finally inserting the ovipositor for around 20–25 minutes, indicating that females first released paralysing venom (envenomisation) ( Fig. 3C ) and then laid the egg. A single egg was laid on or by the side of the host ( Fig. 3D ). The egg has a smooth surface with a typical acuminate form ( Fig. 3E ).

First instar larva hatched in about 84–96 hrs and started feeding on host ( Fig. 3F ). After feeding for 11–14 days the larva started to spin a cocoon near the remains of the host ( Fig. 3G ) and completed it in 36–48 hrs. The newly spun cocoon was cottony white and changed colour to yellowish white in a couple of days and ultimately turned golden brown ( Fig. 3H ). Pupation was completed in 22–26 days and adult emerged 40–44 days after the egg was first laid.

Adult emergence was observed till the first week of October and cocoons which spun in late October entered in diapause and did not show any adult emergence. In the last week of April to early May, the adults started emerging from previous years’ cocoons. In all cases, only a single egg on the host larva or a single larva feeding on the host was observed.

Dissection experiments revealed that adult wasp possesses a pair of ovaries with three ovarioles in each ovary. In five females dissected, a maximum of 6 mature eggs were observed in the ovaries ( Fig. 3J ). Long tubules of the venom gland were attached to a venom reservoir through a common duct. Venom reservoir appeared nearly transparent and had a napiform shape. Dufour gland was pear-shaped with a long stalk and appeared slightly yellowish. In lateral view, the Dufour gland and venom reservoir seem to droop somewhat onto the base of the ovipositor shaft.

Figures

FIGURE 1. Xorides xylotrechi sp. n., holotype female. A–B—habitus; A—lateral view; B—dorsal view; C—terminal antennal flagellomeres; D–F—head; D—frontal view; E—lateral view; F—dorsal view; G–H—mesosoma; G—dorsal view; H—lateral view; I—wings; J—metasoma, dorsal view; K—ovipositor tip, lateral view.

FIGURE 2. Xorides xylotrechi sp. n., paratype male. A–B—habitus; A—lateral view; B—dorsal view; C—antenna; D–E— head; D—frontal view; E—lateral view; F–G—mesosoma; F—dorsal view; G—lateral view; H—metasoma, dorsal view.

FIGURE 3. Biology and reproductive morphology of Xorides xylotrechi sp. n. A—female searching for the host larva; B—female ovipositing; C—host larva; D—paralysed host larva with egg attached; E—parasitoid egg; F—parasitoid 1st instar larva taking a bite; G—parasitoid final instar larva spinning cocoon; H—parasitoid cocoon; I—parasitoid pupa; J—parasitoid female reproductive system (OVR = ovary, OP = ovipositor) and venom apparatus (VG = venom gland, VR = venom reservoir, DF = Dufour gland).