Aloencyrtus obscuratus (Waterston)

Prinsloo, Rd. L., 2010, On some Afrotropical species of Aloencyrtus (Hymenoptera: Encyrtidae): parasitoids of soft scales (Hemiptera: Coccidae), Zootaxa 2716, pp. 1-28 : 22-23

Aloencyrtus obscuratus (Waterston)

( Figs 10, 29, 48)

Coccidoxenus obscuratus Waterston 1917a: 242 .

Trichomasthus obscuratus ; Annecke & Insley 1971: 25.

Aloencyrtus obscuratus ; Prinsloo 1978: 301.

Coccidoxenus niloticus Compere 1940: 405 . Syn. n.

Trichomasthus niloticus ; Annecke & Insley 1971: 25.

Aloencyrtus niloticus ; Prinsloo 1978: 301.

Diagnosis. The female of this species was described and fully illustrated by Compere (1940) and in lesser detail by Waterston (1917). Although both these descriptions contain various inaccuracies, the illustrations are detailed and adequate. Aloencyrtus obscuratus can be distinguished as follows:

Female. Length: about 1.8–2.0 mm. Colour: blackish; head, with moderately strong metallic green and purple reflections, scrobes more brilliant green; mesoscutum with dull bluish-green and purplish reflections, the scutellum mostly bright green to bluish-green. Antenna either more or less uniformly brown or with scape, pedicel and funicle segments I–V yellowish-brown, VI and club brown. Forewing ( Fig. 10) palely infuscated from base of line calva to hyaline band, the disc beyond the band hyaline, the brownish discal setae lending this part of the disc a slightly darkened appearance. Legs, including middle tibial spur, largely blackish-brown except tarsi noticeably paler or with fore and middle tibiae and spur largely yellowish-brown, the basal half of the tibiae with darker suffusions.

Head in dorsal view 4.9–5.0x as wide as frontovertex, anterior margin of the latter medially notched; head in frontal view ( Fig. 29) with scrobes distinctly V-shaped, without a median dorsal fovea. Frontovertex and face densely covered with setigerous punctations, the diameter of each much less than that of median ocellus; genae and temples without punctations. Antenna ( Fig. 48) with pedicel slightly longer than basal funicle segment, latter about 2.25x as long as wide; funicle segments becoming progressively shorter and broader, II–V each longer than wide, V quadrate, VI a little wider than long; club noticeably broader than distal funicle segment, a little shorter than distal three funicle segments combined.

Mesoscutum with fine cellulate-reticulate sculpture, scutellum coarser, mostly longitudinally lineole-reticulate. Forewing ( Fig. 10) 2.1x as long as broad; marginal vein subequal in length to postmarginal, the latter about 0.3x length of stigmal vein. Gaster heart-shaped, distinctly shorter than thorax, the ovipositor not protruding caudally.

Male. As described by Compere (1940) for A. niloticus .

Remarks. Aloencyrtus obscuratus was originally described from a single series of specimens reared from Saissetia somereni (in BMNH) from Ghana. The series comprises a single female “type”, which is the holotype, in addition to a non-type male and female specimen which have erroneously been labeled as “cotypes”.

The type series of A. niloticus (in BMNH and USNM) was originally described from a laboratory stock in California that descended from material reared from Saissetia oleae on oleander in Nairboi, Kenya ( Compere 1940). An undisclosed number of non-type laboratory reared specimens, of which a female and two males are at hand, were listed as additional material by Compere (1940) in the original description of A. niloticus .

A comparison of the available female specimen of A. niloticus with the holotype of A. obscuratus has shown that the two species are synonymous. The only difference between the two specimens is in the colour of the middle tibia, which is largely blackish-brown in the holotype of A. obscuatus , but largely yellowish-brown with darker suffusions basally in the specimen of A. niloticus . I do not believe that this difference is of any specific significance, especially since no other colour of structural differences could be found.

This species can be grouped with A. angustifrons , A. delottoi and A. ugandensis , all of which have the wing disc beyond the pale cross-band hyaline and the entire frontovertex and face distinctly pitted. Aloencyrtus obscuratus is, however, readily separated from these species in the female by the characters mentioned in the foregoing key.

Known distribution. Ghana, Kenya, South Africa.

Type material examined. Aloencyrtus obscuratus : ♀ holotype ( BMNH) with thorax, right wing and right middle and fore leg mounted on a card, the head, with right antenna, on a separate card: “Type; ex Lecanium somereni Newst. On Cola ; 23.xii.15; Aburi, Gold Coast; W.H. Patterson; Coccidoxenus obscuratus Waterst.(1917) ; B.M. TYPE HYM. 5.1, 128” .

Additional material. South Africa. KwaZulu-Natal: Durban , xi.1970, H.P. Insley, ex scale insects on Chaetacme aristata (1 ♀; T3734 ) .

Aloencyrtus niloticus : USA, California, “CES Insectary, Oct.1937, On S. oleae ; Coccidoxenus niloticus Comp. ” (1 ♀, 2 ♂) .