Quadrastichus lasallei, Gates & Chao & Lin & Yang, 2020

Gates, Michael W., Chao, Yi-Min, Lin, Sheng-Feng & Yang, Man-Miao, 2020, Description of two new Quadrastichus (Hymenoptera: Eulophidae) reared from Litchiomyia chinensis (Diptera: Cecidomyiidae) on commercial lychee (Litchi chinensis; Sapindaceae) in Taiwan, Journal of Natural History 54 (9), pp. 635-646 : 637-641

Quadrastichus lasallei , sp. n. ( Figs 1 , 2 )

Female holotype

Length: 3.0 mm. Colour: Head, body, and legs pale yellow, flagellomeres light brown with pale yellow, especially apically ( Figure 1 (b)). Fore wing hyaline, venation yellow.

Head, in frontal view ( Figure 2 (a)), 1.4 X as broad as high, 1.5 X as broad as frontovertex at its narrowest; malar space 0.8 X as long as an eye, the sulcus curved, without a triangular fovea beneath the eye; POL 1.1 X OOL, OOL 2.8 X OD; mandible bidentate with a truncation; head finely setose, eyes sparsely setose, setae short, ~1 ommatidial diameter ( Figure 2 (a)); lower margins of toruli approximately one torulus diameter below lower eye margins; clypeus shallowly emarginate ( Figure 2 (a)).

Antenna ( Figure 2 (d–h)) with scape 5.2 X as long as broad, a little shorter than the height of eye, almost reaching vertex; pedicel approximately 2.5 X as long as broad, 1.5 X as long as basal funicle segment; one transverse anellus present; funicle threesegmented, segments about equal in size, or progressively decreasing a little in size, F1 3.3 X, F2 3.8 X, F3 3.8 X as long as broad; clava 5.0 X as long as broad; apical spine short, distinctly shorter than apical segment ( Figure 2 (h)); sensilla sparse, flagellum rather sparsely setose ( Figure 2 (g–h)).

Mesosoma ( Figure 2 (b–c)) 1.7 X as long as broad; mesoscutum in profile gently convex dorsally, in dorsal view gently rounded laterally; mesoscutal midlobe just longer than broad, with trace of median line posteromedially (difficult to see without high magnification), with 1 adnotaular seta at each side in posterior third; mesoscutum with very fine lineate sculpture; scutellum convex in profile, 1.5 X broader than long with sublateral and submedian lines (difficult to see without high magnification); sculpture much as in mesoscutum; scutellum with 2 pairs of setae; dorsellum convex, smooth, medially about as long as propodeum; propodeum with median carina indistinct, with curved spiracular sulcus mesad reminiscent of paraspiracular carina, with very fine reticulate sculpture; spiracles less than their own diameter from anterior propodeal margin ( Figure 2 (c)); calli each with 2 setae.

Fore wing ( Figure 1 (b)) 2.2 X as long as broad; costal cell 16 X as long as broad, 0.8 X length marginal vein, asetose; submarginal vein with 1 dorsal seta; marginal vein 5.7 X as long as stigmal vein, the postmarginal vein not apparent; subcubital line of setae extending basally as far as basal setal line, closing speculum posteriorly; longest marginal cilia (at the apex of marginal vein) about 0.6 X as long as longest setae on marginal.

Metasoma 1.2 X longer than mesosoma, somewhat circular in dorsal view, just longer than broad, broadly rounded apically; epipygium 1.6 X as long as broad; hypopygium reaching to about half the length of gaster; ovipositor sheaths short hardly protruding apically; one cercal seta twice length others and kinked.

Male

Length: 1.9 mm. Colour: much as in female except following brown: vertex; pronotum dorsally, mesoscutum in anterior half, except along notauli; dorsellum, propodeum, metapleuron, gastral terga 3–8. Differing structurally from the female mainly in the antenna ( Figure 2 (d–f)): scape with a linear ventral plaque, placed in apical half and extending from near apex to beyond mid length of scape ( Figure 2 (f)); a single anellus present; funicle four-segmented, F1 1.0 X F2 2.0 X, F3 2.7 X, F4 2.8X as long as broad, each broadest basally and narrowing apically; clava 5.0 X as long as broad; flagellum sparsely setose, the setae on funicle segments fairly long, slightly curved, basal dorsal whorls on F1 – 4 reaching beyond following segment. Some clava sensilla strongly recurved ( Figure 2 (d–e)).

Variation

One male has additional brown colouration anteriorly on gastral tergum 1, encircling petiole base.

Etymology

Named in honour of our friend and colleague, Dr John La Salle, for his good humour and love of Chalcidoidea. He will be missed.

Biology

Larva is a koinobiont endoparasitoid of mature larva of lychee gall midge, Litchiomyia chinensis .

Diagnosis and recognition. This species is recognised by female completely yellow, clypeus slightly emarginate (both sexes), and male with strongly recurved sensilla on clava.

This species keys to the anysis -group to a large extent, ultimately to couplet 20 in Graham 1991 where it splits the diagnostic features with three of five characters leading to Q. anysis . However, Q. lasallei differs from Q. anysis in completely pale yellow colouration in female (areas of brown/black on head and metasoma, mesosoma mostly black), scape reaching the level of vertex (not reaching vertex), clypeus notched (not subtruncate), and recurved sensilla on male clava (straight). Biologically, Q. anysis is known from Monarthropalpus buxi Laboulbène ( Diptera : Cecidomyiidae ) that mines the leaves of Buxus spp. (box; Buxaceae ) throughout Europe and North America. In the key of Narendran (2007), this species runs to Q. longiclavatus Narendran , but differs in claval spine 0.2 X the length of clava (0.52 X) and female completely yellow (largely black). The biology and male are unknown for Q. longiclavatus . Finally, in the Reina and La Salle (2004) key to Old World species of the anysis -group, Q. lasallei runs to Q. citrella Reina & LaSalle , as both share F1 shorter than F2, and speculum extending ~0.2–0.3 X length marginal vein, but all gastral terga yellow (dark brown band on gastral terga 3–4) and propodeum distinctly reticulate (sculpture much smoother). Further, Q. citrella is an idiobiont ectoparasitoid of the leafminer Phyllocnistis citrella Stainton ( Lepidoptera : Gracillariidae ) whereas Q. lasallei is a koinobiont endoparasitoid of L. chinensis .

Type material examined

Female holotype, 1 female: TAIWAN: Changhua Co.: Fenyuan Township, No. 139 Fongshan Rd., 24°00 ʹ 9.2”N 120°37 ʹ 32.3”E, 19.IX.2018, Heyieh, Coll. Yi-Min Chao; sp. 2, female #6; USNMENT01525925 ( NCHUC). 2 female, 3 male paratypes, same data as holotype ( NCHU) . 2 female, 3 male paratypes, same data as holotype, except secondary labels are sp. 2, female #5, USNMENT01525926 (1 f, USNM); sp. 2 female #6, USNMENT01525927 (1 f, NHMUK); sp. 2 male #7, USNMENT01525928 (1 m, USNM); sp. 2 male #7, USNMENT01525929 (1 m, NHMUK); sp. 2 male #7, USNMENT01525924 (1 m, CNCI) . 1 female paratype, same locality and collector as holotype, except date 13 . XI.2018 (1 f, NCHU). 1 female paratype: Nantou Co.: Caotun Township, Jianxing Rd., 23°59 ʹ 39.7”N 120°46 ʹ 18.1”E, 6.IX.2018, Coll. Yi-Min Chao; sp. 1 male #4, USNMENT01525920 (1 f, CNCI) . 1 female, 4 male paratypes: TAIWAN: Taichung City: Taiping Dist., Guangxing Rd., No.60 2140th S. Ln., 24°07 ʹ 42.4”N 120°44 ʹ 17.1”E, 21. XI.2018, em. 29.XI.2018, Coll. Yi-Min Chao (1 f, 2 m, NCHU); same collected date except em. 27.XI.2018 (2 f, NCHU).

Figures

Figure 1. (a) Quadrastichus johnlasallei, lateral habitus, female. (b) Quadrastichus lasallei, lateral habitus, female.

Figure 2. Quadrastichus lasallei, female: a, anterolateral head; b, dorsal mesosoma; c, propodeum; g, lateral flagellum; h, lateral clava. Q. lasallei, male: d, lateral flagellum; e, lateral clava; f, lateral scape.