Mesopolobus Westwood, 1833: 443

Li, Qin, Dzhanokmen, Klarissa Alekseyevna, Triapitsyn, Serguei Vladimirovich & Hu, Hong-ying, 2018, Parasitoids reared from galls of Stefaniola sp. (Diptera, Cecidomyiidae) on Haloxylon spp. in China, with redescription of Mesopolobus quadrimaculatus Dzhanokmen (Chalcidoidea, Pteromalidae), Turkish Journal of Zoology 42, pp. 263-268 : 264-267

Mesopolobus Westwood, 1833: 443 . Type species: M. fasciiventris Westwood , by original designation and monotypy.

Mesopolobus Westwood : Graham, 1969: 638–681 (synonyms, key to European species); Dzhanokmen 2005: 71–79 (synonyms, annotated list of species from Kazakhstan); Sun et al., 2005: 14 (synonyms, key to Chinese species); Baur et al., 2007: 387–397 (discussion, host associations); Xiao et al., 2016: 65 (synonyms, diagnosis, biology, and distribution).

Diagnosis. Body green with luster; occiput not margined; antenna 13-segmented, inserted below middle of face; antennal formula 11353 or 11263; right mandible 4-toothed and left mandible 3-toothed; pronotum reticulate and its posterior edge with a conspicuous shiny strip, pronotal collar with an abrupt edge but not carinate; notauli incomplete; scutellum without frenal line; propodeum usually with median carina complete and plica developed, at least in posterior third, spiracles elongate; mesepisternum with upper triangular areas smooth; fore wing with speculum extending to marginal vein; costal cell on upper surface bare; gaster sessile.

Biology. The biology of the species in this genus is very diverse. Most species are parasitoids of gall-forming insects on a wide variety of plants including Chenopodiaceae , Salicaceae , Tamaricaceae , and Gramineae. It has been reported that cecidomyiids are common hosts for some species of this genus, with 65 such hosts in Kazakhstan alone ( Dzhanokmen, 2005). Some species of Mesopolobus also parasitize pupae of various insect hosts, including other Diptera , sawflies ( Hymenoptera, Symphyta ), and Bucculatrix variabilis Braun ( Lepidoptera : Bucculatricidae ) ( Bouček, 1988).

Distribution. Cosmopolitan.

Mesopolobus quadrimaculatus Dzhanokmen, 1975

Mesopolobus quadrimaculatus Dzhanokmen, 1975: 629–631 . Type locality: 20 km NE of Ajak-Kalkan, Ili River Valley, Almaty Region, Kazakhstan. Holotype male (Zoological Institute, Russian Academy of Sciences, Saint Petersburg, Russia [ZIN]), examined ( Dzhanokmen, 1975).

Mesopolobus quadrimaculatus Dzhanokmen : Dzhanokmen, 2005: 76 (habitat, distribution, and host associations in Kazakhstan).

Redescription (specimens from Xinjiang). FEMALE. Body length 2.6–4.2 mm (n = 15). Body ( Figure 1a ) metallic blue-green with shine, eye bare; antenna dark brown except scape, pedicel and anelli brown; fore wing hyaline, marginal and postmarginal veins brown, stigmal vein pale yellow; two infuscate transverse maculae below base of marginal vein and apex of postmarginal vein; coxae identical with body color, femora dark brown, tibiae brown, telotarsi dark brown.

Head in frontal view ( Figure 1b ) about 1.2× as wide as high, face with metallic reflections and regular raised reticulations; antennal scrobe broad but not deep, with raised reticulations in its lower part; clypeal margin truncate to slightly emarginate. Antennae inserted below middle of face, at lower ocular line, antennal formula 11353; scape short, not reaching lower margin of anterior ocellus; pedicel about 1.8× as long as broad, about 1.8× as long as fu 1; proportions of length of anelli 13:19:33; funicular segments connected tightly to each other and each with 1 whorl of sensilla; fu 1 to fu 3 each about 1.2× as long as broad; the following two segments slightly broader than long (about 1.2×); clava about 1.9× as long as broad; pedicel and flagellum combined about 0.6× as long as head width. In lateral view, eye height about 1.5× eye width and about 3.0× malar space; malar sulcus linear and complete. In dorsal view, head ( Figure 1c ) about 1.9× as broad as long; POL about 3.5× OOL.

Mesosoma ( Figure 1c ) in dorsal view narrower than head width (about 0.8×); pronotum collar margined with a sharp carina, slightly narrower than mesoscutum width (about 0.9×); mesoscutum about 1.5× as long as broad; scutullum ( Figure 1d ) with strong raised reticulate sculpture, about 1.0× as long as broad; frenal area absent; propodeum ( Figure 1d ) with median area smooth, about 0.3× as long as scutellum; median carina straight and complete; plica sinuate and complete; nucha triangular and small, with fine transverse striations; propodeal spiracles large and subcircular; sides of propodeum smooth and with patches of dense, whitish, straight hairs. In lateral view, prepectus smooth, about 0.8× as long as tegula; entire thoracic pleura regularly reticulate except upper mesepimeron smooth. Fore wing ( Figure 1e ) without basal hairline; basal cell completely bare; speculum large and open posteriorly; marginal vein length about 1.1× postmarginal vein length and about 1.8× stigmal vein length. Metacoxa in dorsal view bare, with fine reticulate sculpture.

Gaster elongate, 1.6–1.9× as long as broad, about 1.0× as long as head plus mesosoma; Gt 1 smooth, with posterior margin medially rounded and projecting, about 0.3× as long as gaster.

MALE. Body length 2.5–2.7 mm (n = 5). Antenna ( Figure 1f ) different from that of female in having pedicel and flagellum about 0.8× as long as head width, funicular segments yellow and clava dark brown, or even black, with some metallic tints.

Diagnosis. Mesopolobus quadrimaculatus is unique among the described species of the genus in having two infuscate transverse maculae on the fore wing disc, one below the base of marginal vein and the other below the apex of postmarginal vein and just beyond the apex of stigmal vein in both sexes.

Both females and males of M. quadrimaculatus from Xinjiang are larger than those from Kazakhstan as described by Dzhanokmen (1975), the body length of which was, respectively, 2.25 mm and 1.3–1.7 mm.

A key to M. quadrimaculatus and M. deserti Dzhanokmen , another taxon newly recorded from China (see Section 4), is provided here.

Fore wing disc with two infuscate transverse maculae, one below base of marginal vein and the other below apex of postmarginal vein and just beyond apex of stigmal vein in both sexes; fu 4 broader than long (about 1.2×); propodeum shorter than half of scutellum (0.33×)……………….... ..... ...................................... M. quadrimaculatus Dzhanokmen

– Fore wing disc hyaline, without maculae in both sexes; fu4 longer than broad (about 1.3×); propodeum more than half of scutellum (0.64×)……………………... …………......................................... M. deserti Dzhanokmen

Material examined. China, Xinjiang: Altay Prefecture, Fuhai , 23– V –2012, Maoling Sheng (from dipteran galls on Haloxylon sp. ), 2♀♀; Fukang (44°22′29″N to 44°22′49″N, 87°52′57″E to 87°52′58″E, 401–446 m), Beishawo Desert, Hong-ying Hu’s group: 12–X–2014, 3♀♀; 26–IV–2015, 2♂♂; 15– V –2015, 3♀♀; 15–X–2016, 7♀♀, 3♂♂ .

Biology. Dzhanokmen (2005) reported that this species is a parasitoid of various Cecidomyiidae . It was reared from galls of various cecidomyiid species on different host plants: from stem-galls of Stefaniola iliensis Fedotova on Haloxylon persicum , from stem-galls of Stefaniola fragosa Mamaev and S. gigas (Marikovskij) on Haloxylon ammodendron , from bud-galls of Halodiplosis meridianus (Marikovskij) on the same host plant, and also from Halodiplosis nanophytonis Fedotova on Nanophyton erinaceum (Pallas) Bunge. Dzhanokmen (2005) also reported adults of this pteromalid species collected on blooming Tamarix spp. ( Tamaricaceae ).

During 2014–2016, we reared M. quadrimaculatus in Beishawo Desert in Fukang, Xinjiang, from stem-galls of Stefaniola sp. on both H. ammodendron and H. persicum . Galls of this cecidomyiid are generally located at the bases of newly grown stems or small branches. At the early infesting stage, the protuberant galls are small. The color of the galls changes from green or yellow to yellowish-brown during the growing season. Finally, the galls desiccate and both ends of the stem turn yellow and also desiccate, as stated by Xue et al. (2012). Both individuals of Stefaniola sp. and M. quadrimaculatus were found in the two cells within the same gall when dissected ( Figures 2a and 2b ). However, generally, only one adult ( Figures 2c–2f ) of M. quadrimaculatus was reared from each stem-gall on both H. ammodendron and H. persicum . The trophic relationship between M. quadrimaculatus and the gall of Stefaniola sp. (and the gall-maker itself) still needs further study as it remains unclear whether the parasitoids feed externally on eggs, larvae, or pupae of this gall-inducer.

LI et al. / Turk J Zool

Distribution. China (Xinjiang) [new record] and

Kazakhstan ( Dzhanokmen, 1975, 2005).

Figures

Figure 1. a–f: Mesopolobus quadrimaculatus Dzhanokmen: a–e (♀), f (♂). a: Body, dorsal view; b: head, frontal view; c: head and mesosoma, dorsal view; d: scutellum and propodeum, dorsal view; e: fore wing; f: head, frontal view, and antennae.

Figure 2. a–f: Development of Mesopolobus quadrimaculatus Dzhanokmen. a–b: Pupa found in the same gall with a larva of Stefaniola sp.; c: pupa; d–f: adult female (d: frontal view, e: lateral view, f: dorsal view).