Aprostocetus felix La Salle, Yang & Lin, 2014

Yang, Man-Miao, Lin, Yu-Che, Wu, Yaojun, Fisher, Nicole, Saimanee, Titiporn, Sangtongpraow, Benjakhun, Zhu, Chaodong, Chiu, William Chien-Hsien & Salle, John La, 2014, Two new Aprostocetus species (Hymenoptera: Eulophidae: Tetrastichinae), fortuitous parasitoids of invasive eulophid gall inducers (Tetrastichinae) on Eucalyptus and Erythrina, Zootaxa 3846 (2), pp. 261-272 : 266-269

Aprostocetus felix La Salle, Yang & Lin , sp. nov.

( Figs 7–12 )

Diagnosis. Aprostocetus felix belongs to the causalis group of species based on the characters given above, and particularly the distinctive coloration of the male gaster. It can be separated from the other species discussed above by the following characters: forewing with speculum partially closed behind, with the cubital line of setae not quite extending to meet the basal line of setae ( Fig. 10 ); propodeum longer than dorsellum, without a curved paraspiracular carina ( Fig. 12 ); F1 more than 1.5× longer than wide ( Fig. 9 ). Male usually with dorsum of mesosoma predominantly yellow to orange yellow, although sometimes mostly dark brown ( Fig. 8 ).

Female ( Figs 7, 9–12 ). Length 1.0– 1.6 mm. Head generally yellow or yellow-orange, occiput brown. Mesosoma yellow or yellow-orange, anterior face of pronotum brown, except some sutures sometimes brown, particularly the notaulus; small brown areas sometimes also present, such as mesepimeron dorsally, and a transverse stripe on propodeum posteriorly. Legs and coxae yellow to yellow-orange, except sometimes with some dark markings. Gaster yellow to yellow-orange with a brown transverse stripe posteriorly on each tergite. Ovipositor sheaths brown.

Head ( Fig. 11 ). Ocellar triangle surrounded by faint grooves. POL 1.4–1.7× as long as OOL. Frontal suture small, v-shaped. Scrobal area without distinct median carina. Torulus placed above level with ventral margin of eye. A broad depression (supraclypeal area) below torulus extending to clypeus. Malar sulcus nearly straight, only slightly curved. Clypeal margin bidentate.

Antenna ( Fig. 9 ) with 3 funicular segments and 3 very small anelli. First and second funicular segments distinctly longer than wide, third slightly longer than wide: length/width ratio of F1 1.6–2.0; F2 1.3–1.5; F3 1.1–1.3. Clava 2.0–2.5× longer than wide. Scape slightly flattened.

Mesosoma ( Fig. 12 ). Pronotum very short medially in dorsal view. Mid lobe of mesoscutum with very weak median line and a single row of 4–7 adnotaular setae on each side. Mesosternum flat just in front of the trochantinal lobes and with precoxal suture. Scutellum with anterior pair of setae located behind middle. Scutellum overhanging dorsellum. Propodeum short medially, slightly longer than dorsellum; with median carina that is split anteriorly and forms a small fovea. Without paraspiracular carina. Propodeum with raised lobe of callus partially overhanging spiracle. Callus with 2 setae.

Forewing ( Fig. 10 ) hyaline. Submarginal vein with 3 dorsal setae. Costal cell with line of ventral setae in apical half. Relative length of wing veins to stigmal vein as follows: CC: MV: STV = 2.5–2.7: 3.33–3.7: 2–3.8: 1. PMV very short, less than one quarter length of stigmal vein. Speculum partially closed behind, with cubital line of setae not quite extending to meet basal setal line. Wing disk beyond speculum densely pilose.

Gaster distinctly longer (1.2–1.3×) than mesosoma. Hypopygium reaching about half length of gaster. Cercus with 1 setae longer than others and sinuate. Ovipositor sheath slightly protruding, very short in dorsal view.

Male ( Fig. 8 ). Length 1.2–1.45 mm. Head yellow with brown markings as follows: occiput, ocellar triangle, sometimes lower eye margin near malar sulcus. Thorax yellow to yellow-orange, generally with brown markings restricted to anterior face of pronotum, propodeum, mesepimeron, and along sutures. Dark specimens sometimes with mesosoma almost entirely brown, dorsellum yellow. Legs and coxae yellow, sometimes with some brown markings. Gaster dark brown, with distinct white patch anteriorly on both dorsal and ventral surfaces, these connected laterally. Antenna with 3 small anelli and 4 funicular segments; F1 quadrate to slightly longer than wide; F2–F4 all distinctly longer than wide; club elongate, 5–6× longer than wide. Each funicular segment and basal club segment with compact subbasal whorls of long setae that extend at least to apex of following segment. Ventral plaque small, one quarter to one fifth length of scape, situated near apex of scape.

Type material. Holotype ♀: Taiwan, Chiayi, Taibao, 9.i.2011, Yu-Che Lin , host Quadrastichus erythrinae [ NCHU].

42♀, 37♂ Paratypes. 5♀, 6♂, Same data as holotype [3♀, 4♂ ANIC; 2♀, 2♂ NMNS] . 2♀, 1♂, Taiwan, Miaoli, Houlung , 20.i.2010, Yu-Che Lin, host Quadrastichus erythrinae [ NCHU] ; 3♀, Taiwan, Taichung, Dali , 29.iii.2010, Yu-Che Lin, host Quadrastichus erythrinae [ NCHU] ; 7♀, 8♂, Taiwan, Taichung, Dali , 21.iv.2012, Ying-Ying Huang, host Quadrastichus erythrinae [ NCHU] ; 10♀, 10♂, Taiwan, Chiayi, Taibao , 24.i.2011, Yu-Che Lin, host Quadrastichus erythrinae [ NCHU] ; 5♀, 3♂, Taiwan, Kaohsiung, Chujin , 10.iii.2012, Ying-Ying Huang, host Quadrastichus erythrinae [ NCHU] ; 10♀, 9♂, Taiwan, Kaohsiung, Chujin , 21.iv.2012, Ying-Ying Huang, host Quadrastichus erythrinae [ NCHU] .

Distribution. Taiwan.

Etymology. The specific name felix is Latin for happy, lucky, fortunate.

Biology. Aprostocetus felix is a solitary parasitoid collected from mature larvae and pupae of Q. erythrinae . In contrast to other parasitoids found on Q. erythrinae in the early stage of the pest invasion, population levels of this species remain high in cooler times of the year when other parasitoid population levels declined. Its population levels have built up through the years and it now occurs all year round in most areas in Taiwan, where it appears to have the potential to be an effective biological control agent of Q. erythrinae (Yang & Lin, unpublished).

Figures

FIGURES 7–12. Aprostocetus felix. 7. Holotype female, habitus. 8. Male habitus. 9. Female antenna. 10. Female forewing. 11. Female head. 12. Female mesosoma.