Encarsia tristis (Zehntner)

Schmidt, Stefan & Polaszek, Andrew, 2007, The Australian species of Encarsia Förster (Hymenoptera, Chalcidoidea: Aphelinidae), parasitoids of whiteflies (Hemiptera, Sternorrhyncha, Aleyrodidae) and armoured scale insects (Hemiptera, Coccoidea: Diaspididae), Journal of Natural History 41 (33 - 36), pp. 2099-2265 : 2248-2249

90. Encarsia tristis (Zehntner)

( Figures 286–288 )

Prospalta tristis Zehntner 1896, p 11 . Syntypes ♀ „, Indonesia: Java (L. Zehntner), ex Neomaskellia bergii [presumed lost].

Aspidiotiphagus aleyrodis Ashmead 1904b, p 139 . Syntypes ♀ „, Philippiines: Manila (USNM, not examined). Synonymy by Gahan 1932.

Limacis aleurodiphaga Risbec 1950, p 621 . Lectotype ♀, Senegal: Bambey, ex Neomaskellia bergii . Synonymy by Huang and Polaszek, 1998: 1956 (includes full synonymy).

Description

Female. Colour: head light brown, vertex and lower parts brown. Mesosoma brown with the following parts dark brown: pronotum, anteromedial patch on mesoscutal midlobe, axillae, mesopleuron, and metanotum. Gaster dark brown. Fore wing largely infuscate.

Morphology: stemmaticum with rugose-reticulate surface sculpture. Antennal formula 1,1,3,3. Pedicel subequal in length to F1. F1 1.44 longer than its maximum width, slightly longer than F2 (1.18) and F3 (1.18). F2 subequal in length to F3. Flagellomeres with the following numbers of sensilla: F1: 4, F2: 4, F3: 4, F4: 4, F5: 5, F6: 3. Midlobe of mesoscutum with eight setae, arranged symmetrically, side lobes with three setae each. Scutellar sensilla widely separated (approximately eight times the maximum width of a sensillum). Distance between anterior pair of scutellar setae larger than distance between posterior pair. Fore wing about 2.7 times as long as width of disc. Marginal fringe 0.32 times as long as width of disc. Basal cell with four setae. Submarginal vein with two setae, marginal vein anteriorly with six setae. Tarsal formula 5-5-5. Apical spur of midtibia longer than half the length of the corresponding basitarsus (0.67). Tergites laterally with the following numbers of setae: T1: 0, T2: 2, T3: 4, T4: 3–4, T5: 5–6, T6: 3–4, T7 with four setae. Ovipositor shorter than midtibia (0.57) and 0.95 times as long as clava. Third valvula 0.33 times as long as second valvifer.

Male. Not collected in the study area. Males from elsewhere are very similar to females in both colour and morphology. Antenna eight-segmented, slight fusion occurring between F5 and F6.

Species group placement. E. tristis group.

Distribution. Australia: Queensland, Western Australia. Asia: Bangladesh, India, Indonesia, Philippines. Africa: Senegal.

Host. Aleyrodidae : Neomaskellia bergii (Signoret) . The following additional hosts have been recorded ( Huang and Polaszek 1998): Aleyrodes sp. on grass ( Shafee 1973), Aleyrodes sp. , Neomaskellia andropogonis , indet aleyrodid, (?) scales ( Hayat 1989a), N. bergii on Saccharum sinensis ( Chou et al. 1996) .

Material examined

Western Australia: 1♀, CALM Site 4/3, 14 km S by E Kalumburu Mission (14 ° 259S, 126 ° 409E), 3–6 June 1988 ( T. A. Weir), Malaise trap, closed forest ( ANIC) .

Comments

The species is recognized by the short ovipositor and the almost quadrate two distal funicular segments. Girault recorded the species from Australia in 1919 ( Girault 1919, p 53) but his material could not be located. In his publication Girault writes that he reared three females from pupae of the sugarcane whitefly, Aleyrodes bergi (5 Neomaskellia bergii ), at Gordonvale, Queensland, on cane, on 9 December 1918. The species has a peculiar colour pattern in that it has two black spots on the mesosoma (i.e. the axillae are black) contrasting with the remaining yellow mesosoma. Also quite unusual are the stout antennae with segments two and three short to almost quadrate.

Figures

Figures 286–288. Encarsia tristis (Zehntner), female. (286) Mesosoma and gaster. (287) Antenna. (288) Fore wing.