Acerophagus artelles, Guerrieri & Noyes, 2010

Guerrieri, Emilio & Noyes, John S., 2010, Acerophagus artelles sp. nov. (Hymenoptera Chalcidoidea Encyrtidae), a biocontrol agent of Dysmicoccus grassii (Leonardi) (Hemiptera Coccoidea Pseudococcidae) on banana in the Canary Islands (Spain), Journal of Natural History 45 (1 - 2), pp. 29-34 : 31-34

Acerophagus artelles sp. nov.

(Figure 1)

Diagnosis. Female (length, including ovipositor, about 0.70 mm): body generally orange, marked with brown; scape pale yellow, with a brown stripe along dorsal margin; pedicel pale yellow, the apical third brown; F1 dusky white, remaining segments dark brown, clava white with basal segment brown; legs pale yellow with joints brown; fore tibia suffused with brown, mid and hind tibiae each with two dark rings (larger and darker on hind tibia); tegula white, apex translucent brown; fore wing with a brown band in the basal third nearly reaching posterior margin, a paler stripe level with setae interrupting the linea calva, and a darker subcircular spot beneath stigmal vein; gaster largely brown; basal third of gonostylus pale yellow, remaining part brown; frontovertex slightly more than one-third head width; scape about 5× as long as broad; funicle 5-segmented with linear sensilla only on F5; clava 3-segmented with outer suture incomplete; palp formula 4-2; wings fully developed; dorsal surface of costal cell with a single line of setae extending about three-fourths towards base; linea Figure 1. Acerophagus artelles ♀. 1. Left antenna. 2. Fore wing venation.

calva interrupted by 8–10 setae; ovipositor about 3× as long as gonostylus or 1.7× as long as mid tibia. Male: unknown.

Female (holotype): length, including ovipositor, 0.70mm; excluding ovipositor, 0.65mm (CPD). Head mostly orange, gena pale yellow, occiput with area above foramen brown; radicle (Figure 1, panel 1) pale yellow, scape pale yellow, with a brown stripe along dorsal margin; pedicel pale yellow, the apical third brown, F1 dusky white (light grey), remaining segments dark brown, clava white with basal segment brown; pronotum dusky white (light grey), neck mixed brown, posterior margin with a lateral pair of small, brown spots; mesoscutum orange, anterior margin marked with brown, axilla and scutellum dorsally orange, metanotum orange-brown; tegula white, apex translucent brown; dorsum of thorax with translucent, white setae; side and ventral part of thorax pale yellow, mesosternum and mesopleuron marked with brown; fore wing (Figure 1, panel 2) with a brown band in the basal third nearly reaching posterior margin, a paler stripe level with setae interrupting the linea calva; and a darker subcircular area beneath stigmal vein; propodeum dorsally brown, side and ventral part pale, dusky yellow; gaster dorsally with T1 brown, remaining tergites dusky orange margined with brown at base and laterally; ventral part of gaster pale dusky yellow or off-white; basal third of gonostylus pale yellow, remaining part brown.

Head with fairly regular, slightly coarse, deep, polygonal reticulate sculpture on frontovertex, mesh equal to eye facet or slightly smaller; frontovertex evenly curved in profile; occipital margin sharp, carinate; eye separated from occipital margin by about half diameter of a facet, glabrous; frontovertex narrowest at level with posterior ocellus and slightly broadening anteriorly, inner eye margins straight; malar suture absent; ocellar angle about 35 ◦; funicle (Figure 1, panel 1) with five segments; clava with outer suture incomplete, sensory area about 0.2× as long as clava; mandible with three acute teeth, upper one the smallest; palp formula 4-2. Relative measurements: HW 40, FVW 11, FVL 25, OD 3, POL 4, OOL 1, OCL 3, AOL 5, EL 27, EW 20, MS 14, SL 25, SW 5.

Dorsum of thorax with moderately deep imbricate-reticulate sculpture finer and shallower than that on frontovertex; dorsum of thorax with moderately dense setae; scutellum 0.8× as long as broad; fore wing (Figure 1, panel 2), with three longer, bristle-like submarginal setae dorsally on marginal and postmarginal veins; linea calva interrupted by six setae and closed posteriorly; propodeum with submedian lines distinct, curved and converging, separated at anterior margin by about 15× diameter of spiracle; propodeal spiracle separated from anterior margin by about 3× its own diameter, apparently connected to a longitudinal carina by a short, shallow, obliquely transverse groove; setae on side of propodeum sparse, only six or seven setae visible outside spiracle. Relative measurements: FWL 90, FWW 35; HWL 63, HWW 15.

Gaster with hypopygium reaching slightly past apex of syntergum; exserted part of ovipositor about one-third as long as either gaster or mid tibia.

Paratype. Antenna with linear sensilla only on F5 and clava; outer plate of ovipositor with only a single subapical seta. Relative measurements: OL 100, GL 32 [ MT 57 ] .

Male. Unknown.

Variation. Very little in the material at hand. Female length can vary from 0.65 to 0.72 mm. Specimens collected in the field in November tend to be darker and with a more evident brown band on the fore wing.

Hosts. All the material has been reared from Dysmicoccus grassii ( Hemiptera : Pseudococcidae ) on banana.

Distribution. Spain, Canary Islands.

Material examined. Type material. Holotype ♀: SPAIN: Canary Islands, Tenerife , Adeje F. Dulce Acevedo, ex Dysmicoccus grassii on banana, x.2009 (E. Hernandez Suarez). Paratypes: 10♀ same data as holotype. Holotype in BMNH . Paratypes in BMNH and DEZA .

Comments. In the key by Gahan (1946), artelles runs to orientalis (Ferrière) ( Ferrière 1937). The two species are extremely similar in general habitus, both having body length not exceeding 0.75 mm, mid and hind tibiae with two brown rings and fore wings with a dark brown spot beneath the stigmal vein. Females of the two species can be separated by the colour of the antenna and fore wing, and by the relative length of the exserted part of the ovipositor. In orientalis both F5 and clava are white, the fore wing is hyaline (except the dark spot beneath the stigmal vein) and the exserted part of the ovipositor is one-fifth the length of the gaster. In artelles F5 and the basal third of the clava are brown, the fore wing has a large fuscous area nearly reaching the posterior margin of the disk from parastigma to the apex of stigmal vein which includes the darker spot beneath it, and the exserted part of the ovipositor is one-third the length of the gaster. Apart from its size, artelles is also similar to maculipennis (Mercet) ( Mercet 1923) described from the Canary Islands and austriacus (Mercet) ( Mercet 1925) from Austria. Females of artelles can be separated from those of maculipennis by their smaller size and colour of the antenna and fore wing. Females of maculipennis are about 1.5 mm long, the funicle is entirely brown, the clava is entirely white and the fore wing has two distinct almost complete brown bands. Those of artelles are about 0.7 mm long, F1 is white, the clava has the basal third brown and the fore wing is hyaline with only a circular brown area beneath parastigma and stigmal vein nearly reaching the posterior margin of the disk. Females of artelles can be separated from those of austriacus by the colour of the clava (brown in the basal third in artelles , entirely white in austriacus ).

The name of the species is derived from Estrella, in honour of Dr Estrella Hernandez (ICIA).

Acknowledgement

The authors wish to thank Dr Estrella Hernandez and staff at ICIA for the material studied.