Peristenus dayi, Goulet & Mason, 2006

Goulet, Henri & Mason, Peter G., 2006, Review of the Nearctic species of Leiophron and Peristenus (Hymenoptera Braconidae: Euphorinae) parasitizing Lygus (Hemiptera: Miridae: Mirini:), Zootaxa 1323 (1), pp. 1-118 : 44-46

Peristenus dayi n. sp.

( Figs. 5 habitus, 11, 17, 26, Table 10)

Type material. Type locality: Canada, Ontario, Guelph. Holotype, female ( CNCI), labelled: [White] “ Canada, Ontario, Guelph Conc. 2, 20.VI.1998 ex: Adelphocoris lineolatus nymphs 4 & 5 [Emergence date] 27.III.1999, S. Lachance ”; [Red] “ HOLOTYPE Peristenus dayi CNC No. 23475” Condition of holotype: Perfect. Allotype male from the same locality but reared on June 16, 1999. Paratypes: all specimens mentioned under “Material examined and range” .

Origin of species name. This species is named in honour of W. H. Day who helped clarify the biology and taxonomy of several species of Leiophron and Peristenus through rearing. This was the only species he studied that was unnamed.

Diagnosis. Clypeus black, punctures dense on head (especially between the lateral ocellus and the inner eye margin) and on frons (surface matt with few shiny spaces between punctures), occurring in temperate regions of eastern North America and before mid June.

Description. FEMALE. Colour. Head and mesosoma black; clypeus usually reddish black or dark brown, rarely black; metasoma usually black, rarely brown. Legs straw coloured (metacoxa almost always straw coloured or brown on dorsal surface). Metatibia usually light reddish brown and apical half occasionally reddish brown, thus almost always concolorous. Metatarsomeres 1–5, metatibia. Palpi; tegula and mandible, except apex, straw coloured. Scape to flagellomere 2 straw coloured, flagellomere 3 or 4 brown and dark brown from 5–9. Stigma uniformly dark brown or with a paler cloud in basal third.

Structure. Flagellum with 20–23 flagellomeres (respectively 13%, 48%, 37% and 2% of 60 specimens) and flagellomeres enlarged in apical half, with at most 2 preapical flagellomeres quadrate or subquadrate. Length of gena behind eye 0.87–1.14 times as long as length of eye. Height of eye 1.06–1.21 times as long as minimum distance between inner eye margins ( Fig. 17 ). Maximum width of head behind eyes subequal (0.94–0.98) to maximum head width at eye level. Occipital carina developed in dorsal third. Metasomal tergum 1 with lateral edges clearly convergent (posterior margin 1.9–2.5 times as wide as narrowest width near base) and elongate (medial length of tergum 1.61–1.91 times maximum width at posterior end). Radial cell length 0.87–1.06 as long as stigma width (as in Figs. 58–63 ). Forewing vein r usually developed and short and basal cell (except extreme base) pubescent.

Sculpture. Punctures on vertex 5–10 µm in diameter, frons and mesoscutum about 10–15 µm in diameter (a little larger than diameter of ommatidia). Punctures 20–25 µm apart on vertex and 5–15 µm apart on frons (in most specimens surface matt with generally shiny surface between punctures) and between lateral ocellus and inner eye margin) ( Fig. 26 ), 5–10 µm apart near antennal socket, 20–25 µm apart on mesoscutum. Punctures in front of median ocellus in most specimens coarse and dense. Punctures on mesopleuron dense and in most specimens finely punctate or smooth on anteroventral surface of mesepisternum in lateral view. Clypeus generally punctate over surface or occasionally almost impunctate. Metasomal tergum 1 with about 10–12 longitudinal ridges, these often anastomosing on disc and forming a puncture­like sculpture.

MALE. Colour. Generally as in female, but metacoxa usually brown, sometimes brown on outer surface and paler on inner and ventral, and rarely completely straw coloured.

Structure. Flagellum with 20–25 flagellomeres (respectively 1%, 1%, 19%, 62%, 10% and 1% of 32 specimens) and flagellomeres narrow in apical 0.5. Height of eye 0.91–1.10 times as long as minimum distance between inner eye margins. Otherwise structure and sculpture as in female.

Taxonomic notes. Among the species of the P. pallipes complex associated with Lygus spp. , P. dayi is nearest P. braunae . Adults of P. braunae differ in flagellomere frequency, mesocoxa and metacoxa colour in females, clypeus and mesepisternum puncture development, clypeus colour, and flight period.

The nearest populations of P. dayi and of P. braunae are 300 km apart. The populations of P. dayi nearest to those of P. braunae are not more similar than distant populations of both species. There is probably no gene flow between these species. Thus, P. dayi is specifically distinct from P. braunae . A summary of measurement differences between P. dayi and P. braunae is given in Table 10.

Host and biological notes. Adults of this species have almost always been reared from Adelphocoris lineolatus , very rarely from Lygus lineolaris . Adults occur from early May to mid June in eastern Ontario and southern Quebec with peak abundance in late May. This is a univoltine species on nymphs of first generation Lygus bugs. Loan (1965) described the biology of this species under P. pallipes associated with Adelphocoris sp.

Material examined and range. 231 (37♂, 103♀ and 91♂ / ♀) adults were studied. Of these, 23 were reared from Miridae and 208 were field collected. The species is known from temperate regions of eastern North America from southernmost Quebec and Ontario to Delaware.

CANADA. QC: vic. Cantley , 45º33'44"N 75º49'09"W (1♂, 2♀) ; vic. Dunham (1♀) ; vic. Frelighsburg , 45º05'’N 72º50'W (1♂) ; vic. Hemmingford , 45º00'56"N 73º32'11"W (12♀) ; vic. Hemmingford , 45º02'41"N 73º31'54"W (4♀) ; Ste. Anne de Bellevue (1♂) ; vic. Ste. Clotilde , 45º10'05"N 73º40'53"W (3♂, 16♀) . ON: Belleville (5♂, 7♀) ; Bells Corner (1♀) ; Constance Bay (1♂) ; vic. Fitzroy Harbour , 45º28'N 76º11'W (3♂, 20♀) ; Guelph , Stone Rd. (1♂, 9♀) ; Guelph , Concession 2 (2♂, 1♀) ; Kemptville (1♂) ; vic. Kinburn , 45º15'N 76º09'W (1♂) ; Marmora (1♀) ; Morepth (1♀) ; Ottawa (3♀) ; Ottawa , 45º23'16"N 75º43'06"W (1♂, 2♀) ; Ottawa , 45º23'00”N 75º42'30"W (3♀) ; 10 km W Richmond (1♂) ; Stittsville (1♂) . USA. DE: Newark (6♂, 7♀, 48; CNCI, USDA). NJ: Blairstown (4♂, 5♀, 43, USDA); Salem Co., Cohensey (1♀) . NY: Ithaca (3♀) ; Greene Co., Freehold (1♂, 3♀) ; Slaterville Springs (1♂) ; Ulster Co., Clintondale (1♂) ; High Falls (1♂) ; Wallkill (1♀) .

Peristenus mellipes group. This group consists of seven species. The punctures on the vertex are fine and scattered between the inner eye margin and lateral ocellus ( Fig. 27 ). The metatibia is dark brown to black in apical 0.6–0.8 at least on dorsal surface (90% of specimens) and metatarsomere 1 is clearly darker than the following tarsomeres (95% of specimens) ( Figs. 10, 12 ). In females, the length of the flagellum relative to the maximum width of the head between the outer eye margins is less than 2.73 in specimens of five species, and in most specimens of P. carcamoi and P. mellipes it is below 2.78, rarely as high as 2.87, the height of the eye relative to the minimum distance between inner eye margins is more than 1.23 in specimens of five species and in most specimens of P. mellipes and P. pseudopallipes is more than 1.23 and rarely as low as 1.21 (Tables 11 to 17) ( Fig. 18 ).

The following seven species are similar and difficult to distinguish from one another. The descriptions are organized based on clypeus colour and then alphabetically to make species comparisons a little easier. Specimens of P.carcamoi , P. mellipes , P. otaniae and P. pseudopallipes have a reddish brown clypeus ( Fig. 18 ) and almost always (about 99.5%) straw coloured metacoxae ( Fig. 48 ). Specimens of P. broadbenti , P. gillespiei and P. howardi have a black clypeus that is almost always (about 99.5%) blackish brown in the apical half.

Figures

FIGURES 1–5. Habitus with frontal view of head. Codes: “a” clypeal colour; “b” metatibial colour; “c” metacoxal colour; “d” forewing colour; “e” mesoscutal colour.

FIGURES 13–24. 13–22. Frontal view of head. Code: “a” ventral edge of clypeus. 23–24. Dorsal view of head.

FIGURES 50–58. 50–52. Forewing. 53–54. Basal and subbasal cells of forewing. 55–58. Radial cell and stigma of forewing.

FIGURES 59–66. 59–63. Radial cell and stigma of forewing. 64. Hind wing. 65–66. Basal and subbasal cells of hind wing.

FIGURES 25–36. 25–27. Dorsal view of head with insert to show sculpture. 28–31. Lateral view of head. 32–33. Posteroir view of head. Code: “a” dorsal end of occipital carina. 34. lateral view of antenna. 35–36. Last five flagellomeres in lateral view.

FIGURES 6–12. 6–9. Habitus with frontal view of head. Codes: “a” clypeal colour; “c” metacoxal colour; “f” metafemoral colour; “g” facial colour; “h” genal spot. 10–12. Lateral view of metatibia.

FIGURE 37–49. 37. Lateral view of antenna. 38–39. Last six flagellomeres in lateral view. 40–44. Dorsal view of mesosoma. 45–49. Lateral view of mesosoma.