Necremnus cosconius (Walker, 1839)

Gebiola, Marco, Bernardo, Umberto, Ribes, Antoni & Gibson, Gary A. P., 2015, An integrative study of Necremnus Thomson (Hymenoptera: Eulophidae) associated with invasive pests in Europe and North America: taxonomic and ecological implications, Zoological Journal of the Linnean Society 173 (2), pp. 352-423 : 388-390

NECREMNUS COSCONIUS (WALKER) ( FIGS 57–71 )

Eulophus cosconius Walker, 1839: 145 . ♂ lectotype (BMNH, here designated).

Eulophus amempsimus Walker, 1839: 186–187 . ♀ lectotype (BMNH, here designated); synonymy under N. leucarthros by Boucˇek (1959: 151), and under N. cosconius by Boucˇek & Askew (1968: 65).

Necremnus punctifrons Thomson, 1878: 235 . ♀ lectotype (LUZN, not examined); lectotype designation by Hansson (1991: 33); synonymy under N. folia by Boucˇek, 1959: 152, and under N. cosconius by Bouček & Askew (1968: 65).

Necremnus cosconius ; Graham, 1959: 184.

Type material

Walker (1839) described Eulophus cosconius based on at least six males, the description including also five varieties, from material collected in May and September near London , Isle of Wight , Dorsetshire , Cornwall , and Ireland. The BMNH has three males indicated to form part of the type series. A card-mounted male ( Fig. 65 ) has the following seven labels: (1) a circular, purple-bordered label with ‘LECTOTYPE’; (2) a circular label with ‘38-/7.12/4’ on three separate lines; (3) a small, rectangular handwritten label with ‘ Britain’ ; (4) a rectangular label with ‘ Eulophus Cosconius Walker’ written on one side and ‘ Stood under this name in old B.M. Coll. C. Waterhouse. ’ printed on the other side; (5) a rectangular label with ‘ Britain’ handwritten; (6) a rectangular label with ‘ Eulophus Cosconius Walker LECTOTYPE: ♂ M. de V. Graham det. 1958’ partly printed and handwritten; and (7) a square label with ‘ B.M. TYPE HYM. 5.2504’. The lectotype is entire. The other two males have a circular, blue-bordered ‘PARALECTOTYPE’ label. Both have the ‘Britain’ label, one also has a circular label with ‘38/7.12/3’, and the other has a handwritten label with ‘ Cosconius ’. As Graham did not validly designate a lectotype through publication under ICZN rules, in order to stabilize the concept of the name we designate the male with Graham’s lectotype label as the lectotype and the other two males as paralectotypes of E. cosconius .

Walker (1839) described Eulophus amempsimus based on at least ten females, the description also including nine varieties, from material collected April to October from near London , Isle of Wight, Wales, and Scotland. The BMNH has six females indicated to form part of the type series. A point-mounted female ( Fig. 57 ) has the following six labels: (1) a circular, purple-bordered label with ‘LECTOTYPE’; (2) a circular label with ‘38./4.5/411’ on three separate lines; (3) a rectangular label with ‘ Eulophus Amempsimus Walker’ written on one side and ‘ Stood under this name in old B.M. Coll. C. Waterhouse. ’ printed on the other side; (4) a rectangular label with ‘ Britain’ handwritten; (5) a square label with ‘ B.M. TYPE HYM. 5.2503’; and (6) a rectangular label with ‘ Eulophus amempsimus Walker LECTOTYPE: ♀ M. de V. Graham det. 1958’ partly printed and handwritten. Of the other five females, one has a circular, red-bordered label with ‘Type’ and a handwritten label with ‘ Amempsimus ’. The other four females have the same double-sided label as the one labelled as lectotype, one also has a circular label with ‘38/4.5/410’, one a similar label with ‘38/ 7.12/66’, one a small rectangular label with ‘2’, and one a similar label with ‘977’. As Graham did not validly designate a lectotype through publication under ICZN rules, in order to stabilize the concept of the name we designate the female with his lectotype label as the lectotype. We designate the other five females as paralectotypes of E. amempsimus and have labelled them as such because they did not previously have paralectotype labels.

Description

Female (lectotype of E. amempsimus )

Body ( Fig. 57 ) about 2.4 mm in length. Head primarily dark green with coppery lustre, particularly face, under some angles of light. Antenna ( Fig. 58 ) with scape similarly dark as flagellum; length of flagellum + pedicel about 0.9 × width of head; flagellum with length of F1 + anelli about 1.7 × dorsal length of pedicel and about 2.4 × as long as wide, F2 about 1.4 ×, F3 funicular about 1.3 ×, and clava about 2.3 × as long as wide. Mesosoma dark green with variably distinct and extensive coppery to violaceous-coppery lustres under different angles of light ( Figs 57, 60 ); tegula uniformly dark brown. Mesonotum ( Fig. 60 ) with mesoscutum mesh-like reticulate; scutellum reticulate-imbricate lateral to midline with only mesal margins of reticulations distinct and surfaces only slightly concave ( Fig. 62 ). Fore wing faintly but distinctly bimaculate, with brownish infuscation behind stigmal vein and base of marginal vein ( Fig. 59 ); basal cell apically and speculum posteriorly delineat- ed by complete rows of setae, but mediocubital fold with only one seta basal to setae marking juncture of basal and mediocubital folds ( Fig. 64 ); speculum broadly bare dorsally ( Fig. 64 ); approximate ratio of cc: mv: stv: pmv = 79:75:20:24. Legs dark except with protibia dorsolongitudinally, knees narrowly, and basal two tarsomeres of middle and hind legs pale. Metanotum with dorsellum very shallowly reticulate-imbricate to imbricate-alutaceous ( Figs 60, 62 ). Propodeum ( Figs 60, 62 ) with median carina over slightly more than basal half, otherwise entirely or mostly mesh-like alutaceous to alutaceous-imbricate, the sculpture sometimes strong- er, with raised ridges, only posterolaterally; spiracle comparatively large, separated from posterior margin of metanotum by about 0.5 × minimum internal diameter. Gaster ( Fig. 57 ) brown with slight greenish lustre basally; about 1.9 × as long as wide and about 1.3 × length of mesosoma; syntergum short.

Male (lectotype of E. cosconius )

Body ( Fig. 65 ) about 1.6 mm in length. Head primarily bright green with bluish purple lustre within scrobal depression. Antenna ( Fig. 65 ) with scape about 4.1 × as long as wide; length of funiculars and clava about 1.2, 1.6, 1.6, 2.3, and 2.8 × length of pedicel, with F4 about 3 × and clava about 3.4 × as long as wide; rami with long, hair-like setae, elongate-slender with R1 about 2.3 × length of scape, R1 without mps, R2 with single mps on either side near base, and R3 with one or two mps on either side near base ( Fig. 67 ). Mesosoma bright green similar to head, without distinct coppery lustre ( Fig. 65 ); tegula uniformly brown. Mesonotum with mesoscutum mesh-like reticulate; scutellum lateral to midline imbricate to very shallowly reticulate-imbricate, the reticulations flat or with only mesal margins slightly raised ( Fig. 66 ). Fore wing hyaline ( Fig. 65 ); basal cell apically and speculum posteriorly delineated by complete rows of setae, but mediocubital fold with only one or two setae basal to seta marking juncture of basal and mediocubital folds ( Fig. 71 ); speculum broadly bare dorsally ( Fig. 71 ); approximate ratio of cc: mv: stv: pmv = 61:54:17:22. Legs ( Fig. 65 ) dark except with protibia dorsolongitudinally, knees and basal tarsomeres pale, the second tarsomeres yellowish to brown and apical two tarsomeres brown. Metanotum with dorsellum mesh-like coriaceous-imbricate ( Fig. 66 ). Propodeum ( Fig. 66 ) with median carina over less than basal half, otherwise mesh-like coriaceous to alutaceousimbricate; spiracle comparatively large, separated from posterior margin of metanotum by about 0.5 × minimum internal diameter.

Distribution

Europe (see Noyes, 2013).

Hosts

Unknown (see Noyes 2013 for plant associates).

Discussion

The paralectotypes of N. amempsimus vary in the colour of the mesosoma, sometimes being more extensively dark green with less distinct violaceous-coppery lustre ( Fig. 61 ) than for the lectotype ( Fig. 60 ). Some also have the second tarsomeres yellowish to brown, the fore wing infuscation less distinct or the mediocubital fold with up to two setae basal to the seta that delimits the junction of the basal and mediocubital folds. However, all of the females designated as paralectotypes of E. amempsimus seem to be conspecific except for the one with the circular label stating ‘38/4.5/410’, which is N. tidius based on fore wing setal pattern (narrow speculum and more extensively setose mediocubital fold) in combination with length of the postmarginal vein. The species identity of the ‘38/7.12/66’ female is less certain because it lacks evident fore wing infuscation and appears to have a somewhat longer postmarginal vein, making it more similar to N. tidius -group females, although the propodeal spiracle is slightly separated from the metanotum and the mesosoma is comparatively darkly coloured.

Eulophus amempsimus was first synonymized under N. leucarthros by Boucˇek (1959) and subsequently under N. cosconius by Boucˇek & Askew (1968) based on the opinion of Marcus Graham, but in both instances without giving reasons for the synonymy. Even though males are a much brighter green than are females (cf. Figs 57 , 65 ), the sex association between N. amempsimus (female) and N. cosconius (male) is probably correct based on type material of both apparently having a comparatively short postmarginal vein, the propodeal spiracles being slightly separated from the metanotum (cf. Figs 62 , 66 ), and having similar scutellar sculpture patterns. Females of the type series of N. amempsimus have the scutellum quite distinctly reticulate-imbricate ( Fig. 62 ) or even somewhat scalloped in appearance. Males of the type series of N. cosconius have a similar pattern although the sculpture is shallower and therefore less distinct ( Fig. 66 ), but this is probably correlated with their smaller body size relative to females.

Differentiation of female N. cosconius and N. leucarthros can sometimes be questionable, particularly for females in which the length of the postmarginal vein cannot be measured accurately. Females are similar in colour pattern, sculpture, and structure, including both having the propodeal spiracles slightly separated from the metanotum and uniformly dark tegulae. Although N. leucarthros females have a longer postmarginal vein, the apical limit of this vein can sometimes be difficult to discern, particularly card-mounted females with the wings glued to the card, and some females that we identify as N. cosconius have the postmarginal vein approaching 1.3 × the length of the stigmal vein. However, those N. leucarthros females for which the postmarginal vein cannot be measured accurately always have entirely hyaline fore wings and usually are much brighter green to bluish-green without extensive coppery lustre ( Figs 140, 141 , 145 ). Typical females that we identify as N. cosconius have the fore wings at least faintly, inconspicuously infuscate behind the base of the marginal vein and/or the stigmal vein and usually are a darker green with variably extensive coppery to violaceous-coppery lustres ( Figs 57, 60–62 ). Females of both species appear to have a variable number of setae on the mediocubital fold basal to the basal fold, with up to four setae within about its basal half in N. cosconius . The morphological limits of N. cosconius and N. folia are also not fully resolved because of presence or absence and variation in fore wing infuscation and the reliability of scutellar sculpture and protibial colour pattern for differentiating females of the two species (see under N. folia ) The fore wing colour pattern of typical N. cosconius females ( Fig. 59 ) is similar to some N. artynes -group females, but the latter have F1 comparatively much longer (cf. Figs 14 , 58 ).

Paralectotype males of N. cosconius have one or two mps on either side of the second and third ramus within the basal half of the respective ramus ( Fig. 68 ). As all have their fore wings glued to the card mounts ( Figs 69, 70 ), we are unsure of the exact length of the postmarginal vein relative to the stigmal vein.

Figures

Figures 57–64. Necremnus cosconius. 57–60, Eulophus amempsimus, lectotype ♀: 57, dorsal habitus; 58, antenna; 59, left fore wing; 60, dorsal mesosoma. 61; ♀ dorsal mesosoma (2013-44). 62–64, E. amempsimus, lectotype ♀: 62, scutellum and dorsellum; 63, stigmal and postmarginal veins; 64, base of fore wing.

Figures 65–71. Necremnus cosconius, ♂ lectotype (LT) or paralectotype (PLT). 65, LT dorsal habitus; 66, PLT scutellumpropodeum; 67, LT flagellum; 68, PLT R2 and R3; 69, LT fore wing; 70, stigmal and postmarginal veins; 71, base of fore wing. Arrows point to multiporous plate sensilla in 67 and 68.

Figures 139–144. Necremnus leucarthros (Eulophus anaxippus, ♀ lectotype). 139, head and antennae; 140, dorsal habitus; 141, dorsal mesosoma; 142, tegula (arrow); 143, scutellum-propodeum; 144, fore wing base.

Figures 145–150. Necremnus leucarthros. 145, ♀ dorsal habitus (2013-72); 146, ♀ lateral habitus (2012-2); 147, ♀ scutellumpropodeum (2012-72); 148, ♀ fore wing base (2013-73) (arrow points to subcubital setal line); 149, ♀ head and antennae (2012-2); 150, ♂ head and antenna (2012-3).

Figures 8–16. Necremnus artynes. 8–10, habitus: 8, ♀ lateral; 9, ♂ lateral; 10, ♀ dorsal. 11, ♀ dorsal mesosoma (2012- 5). 12, ♀ fore wing. 13, ♀ metanotum and propodeum (2012-5). 14, ♀ antenna. 15, ♂ pedicel and scape. 16, ♂ antenna.