Peristenus gillespiei, 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 : 58-60

Peristenus gillespiei n. sp.

(Table 16)

Type material. Type locality: Canada, British Columbia, West Harrison Road. Holotype, female ( CNCI), labelled: [White] “ Canada, BC West Harrison road 49º16'26"N 121º52'41"W 20.VI.2001, emg. 19.V.2002 D. Gillespie, clover”; [White] “Ex Lygus shulli Knight Code : WHR20VI01Ls19V02”; [Red] “ HOLOTYPE Peristenus gillespiei CNC No. 23479”. Condition of holotype: excellent. Allotype male from Canada, BC, Silver & Skagit Rd., 22.VI.2000 49º14'N 121º23'W to 49º08'N 121º16'W, 450–600 ms. Paratypes: all specimens reared from the following localities in Canada, BC: West Harrison road; 20–25 km SE Chilliwack Lake road; Hemlock Valley ski hill; Mount Cheam ; 30 km S Skagit Valley road .

Origin of species name. This species is named in honour of David Gillespie who worked for many years on Lygus endoparasitoids. He reared several species, which benefited markedly our species concept along the Pacific coast of Canada. Moreover, Dave was instrumental in actively supporting our sampling efforts, which led to the discovery of new species of Peristenus and Leiophron in western British Columbia.

Diagnosis. Clypeus black or dark brown, frons not densely punctate (especially between lateral ocellus and inner eye margin), forewing vein r generally developed, and a univoltine life cycle associated with first generation of Lygus nymphs.

Description. FEMALE. Colour. Head and mesosoma black; metasoma black. Legs generally straw coloured, metacoxa brown to black; basal 0.3–0.5 of metatibia usually straw coloured or occasionally light reddish brown, and apical 0.5–0.7 of metatibia, and metatarsomere 1 clearly darker than base of metatibia, but metatarsomeres 2–5 less dark than metatarsomere 1. Palpi, tegula and mandible (except apex) straw coloured. Scape to flagellomere 2 straw coloured, thereafter brown to dark brown. Stigma dark brown but straw coloured in basal third.

Structure. Flagellum with 18–20 flagellomeres (respectively 12%, 53% and 35% of 17 specimens) and flagellomeres enlarged in apical 0.5. Few of the preapical flagellomeres subquadrate (none 35%, one 50%, two 9% and three 6%). Length of gena behind eye 0.80–1.00 times as long as length of eye. Height of eye 1.36–1.46 times as long as minimum distance between inner eye margins (as in Fig. 18 ). Maximum width of head behind eyes subequal (0.92–0.96) to maximum head width at eye level. Occipital carina developed in dorsal third. Metasomal tergum 1 with lateral edges clearly convergent (posterior margin 2.2–2.5 times as wide as narrowest width near base) and elongate (medial length of tergum 1.5–1.8 times maximum width at posterior end). Radial cell length 0.83–1.06 as long as stigma width (as in Figs. 58–63 ). Forewing vein r of forewing in most specimens clearly developed (95% based on 100 specimens) and short (as in Figs. 60, 61 ) and basal cell of forewing (except extreme base) pubescent (as in Fig. 54 ).

Sculpture. Punctures on vertex 5–10 µm in diameter, on frons and mesoscutum about 10–15 µm in diameter (a little larger than diameter of ommatidia). Punctures 20–25 µm apart on vertex (especially between lateral ocellus and inner eye margin), 5–15 µm apart on frons to 5–10 µm apart near antennal socket, and 20–25 µm apart on mesoscutum. Punctures on mesopleuron generally dense occasionally scattered. Clypeus generally smooth, rarely punctate all over. Metasomal tergum 1 with about 10–12 longitudinal ridges, these often anastomosing on disc and forming a puncture­like sculpture.

MALE. Colour. As in female.

Structure. Flagellum with 21–23 flagellomeres and flagellomeres narrow in apical 0.5. Height of eye 1.00–1.14 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 with a black or dark brown clypeus, P. gillespiei is nearest P. broadbenti . Almost no structural differences were found between the two species. However, adults of the two species differ in their life cycle and their almost allopatric range (narrowly sympatric in the Cascade Mountains). A summary of measurement differences between P. gillespiei and P. broadbenti is given in Table 16.

Adults of P. gillespiei differ from those of P. howardi in the development of the forewing vein r, the common presence of males, and the univoltine life cycle. A summary of measurement differences between P.gillespiei and P. howardi is given in Table 16.

Adults of P. gillespiei could easily be confused with those of P. braunae a darkly coloured species. They are easily distinguished from those of P. braunae by the colour of the clypeus and metatibia, by the puncture density on the vertex especially between the lateral ocellus and the inner eye margin, by the the ratio of eye height to minimal distance between eye inner margins, and the ratio of length of flagellum to maximum width of head between outer eye margins.

Host and biological notes. Adults of this species have been reared from various species of Lygus . Adults occur from early May to late June, with peak abundance probably in early June but late July at higher elevations (e.g., subalpine meadows). This is a univoltine species. Females of this species parasitize nymphs of only the first nymphal generation of Lygus .

Material examined and range. 53 (13♂, 40♀) adults were studied. Of these, 20 were reared from Miridae and 33 were field collected. The species is known from the Cascades and Coastal ranges to the lowlands from British Columbia to California.

CANADA. BC: Boston Bar , 15 km N, 49º58'39"N 121º52'41"W (6♀) ; Mount Cheam (1♀) ; vic. Chilliwack , 49º07'32''N 122º06'10''W (3♀) ; Chilliwack Lake Rd. , 49º06'N 121º36'W, 800 m (3♂, 4♀) ; Chilliwack Lake Rd. , 20–25 km SE (2♀) ; Delta , 49º04.996'N 123º00.949'W (1♀) ; Gagnon Rd. , 10 km W Terrace (5♀) ; Harrison Bay (3♀) ; Hemlock ski hill, 49º22.846'N 121º56.111'W, 700 m (4♂, 5♀) ; vic. Hope , 49º22'47''N 121º31'22''W (1♂) ; Kleana Cr. , 21 km E Terrace (1♂) ; Silver and Skagit Rd., between 49º14'N 121º23'W and 49º08'N 121º16'W, 450–600 m (2♂, 1♀) ; Skagit Valley Rd. , 30 km S, 49º08'43''N 121º17'36''W (1♂) ; Terrace , 29 km SW (1♀) ; Terrace , 51 km SW (1♀) ; West Harrison Rd. , 49º16'26''N 121º52'41''W (7 ♀) . USA. CA: Monterey Co., Big Creek Station , 1450 m (1♂) .

Figures

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.