Aprostocetus causalis La Salle & Wu, 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 : 264-266

Aprostocetus causalis La Salle & Wu , sp. nov.

( Figs 1–6 )

Diagnosis. Aprostocetus causalis belongs to the causalis group 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 completely closed behind, with the cubital line of setae extending to meet the basal line of setae ( Fig. 4 ); propodeum with a curved paraspiracular carina ( Fig. 6 ); antenna with F1 less than 1.5× longer than wide ( Fig. 3 ). Male with dorsum of mesosoma predominantly dark brown ( Fig. 2 ).

Female ( Figs 1, 3–6 ). Length 0.8–1.4 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. Legs and coxae yellow to yellow-orange. Gaster yellow to yellow-orange ventrally, darkened dorsally; darkened areas ranging from a brown transverse stripe posteriorly on all tergites to entire dorsal surface brown. Ovipositor sheaths brown.

Head ( Figs 5 ). Ocellar triangle surrounded by faint grooves. POL 1.2–1.3× 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. 3 ) with 3 funicular segments and 3 very small anelli. First and second funicular segments slightly longer than wide, third subquadrate: length/width ratio of F1 1.1–1.3; F2 1.1–1.35; F3 0.9–1.05. Clava 1.7–2.2× longer than wide. C3 short and its end broad, not tapering apically, although with small terminal spine. Scape slightly flattened.

Mesosoma ( Fig. 6 ). Pronotum very short medially in dorsal view. Mid lobe of mesoscutum with very weak median line and a single row of 4–6 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, subequal in length to dorsellum; with weak median carina and distinct, curved paraspiracular carina. Propodeum with raised lobe of callus partially overhanging spiracle. Callus with 2 setae.

Forewing ( Fig. 4 ) hyaline. Submarginal vein usually with 3 or 4 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 = 2.9–3.1: 3.2–3.8: 1. PMV very short, less than one quarter length of stigmal vein. Speculum small and closed behind by cubital line of setae extending to basal setal line. Wing disk beyond speculum densely pilose.

Gaster distinctly longer (1.3–1.5×) 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. 2 ). Length 0.75–1.2 mm. Head brown, face yellow. Thorax brown except sometimes with some slight orange markings; dorsellum yellow. Legs and coxae yellow except sometimes with 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 extending at least to apex of following segment. Ventral plaque small, less than one fifth length of scape, situated near apex of scape.

Type material. Holotype ♀, China, Guanxi , Fangcheng, 14.xi.2008, L. Dewei, Wu Yaojun, C. Mingshan, ex galls on Eucalyptus spp. [ IZCAS].

57♀, 41♂ Paratypes. 53♀, 34♂, Same data as holotype [18♀, 10♂ IZCAS; 15♀, 10♂ ANIC; 4♀, 2♂ NCHU; 4♀, 2♂ NMNS; 4♀, 2♂ KUBT; 4♀, 4♂ USNM; 4♀, 4♂ BMNH] ; 4♀, 7♂, Thailand, Kanchanaburi Prov., Phanomthuan , xi.2008 [3♀, 5♂ KUBT; 1♀, 2# ANIC] .

Distribution. China, Thailand

Etymology. The specific name causalis is Latin for fortuitous

Biology. Aprostocetus causalis is a solitary endoparasitoid. In Thailand, the mean longevity of female and male adults fed with honey solution is 18.67 ± 1.93 and 13.33 ± 1.75 days, respectively. The female oviposits in mature larva and pupa of L. invasa . Mean developmental time from egg to adult stage is 12.92 ± 0.92 days ( Sangtongpraow and Charernsom 2012).

Figures

FIGURES 1–6. Aprostocetus causalis. 1. Holotype female, habitus. 2. Male habitus. 3. Female antenna. 4. Female forewing. 5. Female head. 6. Female mesosoma.