Acerophagus Smith

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 : 30-31

Genus Acerophagus Smith

Acerophagus Smith, 1880: 83 . Type species: Acerophagus coccois Smith , by monotypy.

Pseudaphycus Clausen, 1915: 41 . Type species: Aphycus angelicus Howard , by monotypy. Synonymy with Acerophagus by Trjapitzin, 2008: 167.

Diagnosis. Female (length about 0.6–2.0 mm): head always partially or completely pale yellow to pale orange, sometimes with brown areas, matt and never with a metallic sheen; thorax and gaster varying from completely pale yellow to largely orange-brown, sometimes with brown areas; darker specimens normally with clava white, contrasting with brown funicle segments; posterior margin of pronotum always translucent white, yellow or pale orange and frequently with a pair of lateral brown spots; wings sometimes reduced, but in fully winged forms varying from hyaline to weakly infuscate with a paler band distad of venation, venation pale yellow to pale brown; gaster pale yellow to generally off-white frequently marked with brown on T1, posterior margins of T2–T6, and as a transverse subapical band on syntergum; occipital margin sharp; frontovertex with polygonal reticulate sculpture of mesh size subequal to diameter of eye facet; antennal torulus low on head, separated from mouth margin by not more than half its own length and with dorsal margin well below lowest eye margin; upper tentorial arm rod-like and very conspicuous in cleared, slide-mounted material, connecting with frontovertex about midway between torulus and eye margin; mandibles slender with three acute teeth, middle tooth longest, upper tooth sometimes reduced; palp formula virtually always 4-2, rarely otherwise (3-2, 3-1, 2-1); funicle 5-segmented, very rarely 6-segmented, linear sensilla mostly only on clava and distal funicle segment, more rarely on the last two segments or more, sometimes absent from funicle; funicle segments relatively short, usually strongly transverse with proximal segments shorter; clava almost always 3-segmented, asymmetric with outer suture always at least slightly oblique, and sensory area relatively large, giving the clava an obliquely truncate appearance; notaular lines visible at extreme anterolateral corners of mesoscutum, never distinct; axillae meeting medially; mid tibial spur never serrate, varying from a little over half as long as basitarsus to about as long; marginal vein usually punctiform, rarely as much as twice as long as broad, postmarginal vein varying from absent to about half as long as stigmal; marginal vein together with postmarginal vein with 2-4 conspicuous suberect, submarginal setae; linea calva often interrupted, usually closed; costal cell with at least some setae dorsally; mesopleuron clearly separated from gaster by propodeum, which more or less broadly touches hind coxa; propodeum with setae often numerous, but never silvery and very conspicuous; hypopygium reaching apex of gaster and more or less V-shaped; outer plate of ovipositor slender, at least about 4× as long as broad, virtually always with only one subapical seta, rarely two; ovipositor at least as long as mid tibia, rarely slightly shorter; second valvifer without subapical setae; gonostylus free and varying from a little more than one-quarter as long as mid tibia to very slightly longer than mid tibia. Male (length about 0.5–1.3 mm): generally very similar to female but often slightly darker with a wider frontovertex; clava solid.

Distribution. Cosmopolitan.

Hosts. Where their hosts are known, all species have been recorded as primary parasitoids of mealybugs ( Hemiptera : Pseudococcidae ).

Identification. Gahan, 1946 (species of Pseudaphycus ), Rosen, 1969 (species of Acerophagus ); Rosen, 1981 ( Pseudaphycus angelicus group).

Comments. The genus group name Pseudaphycus was attributed to Timberlake (1916) by Trjapitzin (2008) and others, but the name was initially made available by Clausen (1915) because he used it in combination with an available specific name. This meets with the minimum requirements of the International Code of Zoological Nomenclature ( ICZN, 1999; Articles 12.1 and 12.2.5) to make a genus group name available. In the past, Acerophagus has been interpreted to include only species with a 5-segmented funicle. However, four species being described from Costa Rica (Noyes, in preparation) have the funicle 6-segmented. The species of Acerophagus that are predominantly yellow are taxonomically amongst the most difficult of all encyrtids. They present very few useful taxonomic characters and almost always require slidemounting for their identification. Their small size and pale colour makes this difficult, and dissection or orientation of some body parts, especially antennae, can make accurate measurements difficult or even impossible for comparative purposes.