Diglyphus clematidis Navone & Hansson

Hansson, Christer & Navone, Paolo, 2017, Review of the European species of Diglyphus Walker (Hymenoptera: Eulophidae) including the description of a new species, Zootaxa 4269 (2), pp. 197-229 : 199-200

Diglyphus clematidis Navone & Hansson sp. n.

Figs 5, 6 , 77 , 78

Diagnosis. Scape pale with upper anterior corner infuscate; femora and tibiae white ( Figs. 5, 6 ) (small males can have basal ½ of hind femur brown); mesoscutum and scutellum purple, or golden-green with purplish reflections ( Figs 5, 6 ); scutellar disc strongly transverse, 0.80–0.86× as long as wide ( Figs 5, 6 ); fore wing speculum with a few scattered setae (as in Fig. 72 ); male: marginal vein very enlarged, at least 1.2× as wide as width of costal cell at level of base of marginal vein ( Fig. 77 ); gaster with a large pale spot subbasally ( Fig. 6 ).

Material. Holotype female with three labels (white, green and red): “Ceriale (SV) fraz. Peagna - 22.08.2015 - sf. 2.09.2015 - Leg. P. Navone”; “ Phytomyza vitalbae , Clematis vitalba ”; “♀”, “Holotypus Diglyphus clematidis Navone & Hansson ” (in BMNH). Paratypes: 6♀ 7♂ from the same locality and host as holotype; following specimens from the same collecting date as the holotype but emerged: 31.VIII.2015 (1♂) , 30.VIII.2015 (2♂), 1.IX.2015 (3♀ 1♂), 2.IX.2015 (1♂), 4.IX.2015 (1♀); two specimens from the same locality and host as holotype but collected 16.VII.1995, emerged 22.VII.1995 (1♂) , 28.VII.1995 (1♀); two specimens from the same locality and host as holotype but collected 21.IX.2015, emerged 1.X.2015 (1♀) , 4.X.2015 (1♂); one specimen from the same locality and host as holotype but collected 26.VII.2016, emerged 02.VIII.2016 (1♂) . Paratypes are deposited in BMNH (1♀ 2♂), MZLU (1♀ 1♂), PN (remainder of specimens). Each specimen is mounted between two round cover glasses that are glued to a card with a round hole to fit the specimen.

Description. FEMALE. Length 0.9–1.6 mm. Scape pale with upper-anterior corner infuscate, pedicel pale with proximal part infuscate, flagellum light brown to yellowish. Frons below frontal suture metallic green with golden or bluish reflections, with a small yellow spot just below toruli; frons above frontal suture and on vertex metallic purple. Pronotum purple; mesoscutum purple or bluish-purple, anterior part more or less golden-green ( Fig. 5 ); scutellum purple ( Fig. 5 ); dorsellum (and lateral part of metanotum) and propodeum golden-green, metallic olive or bluish-green. Fore and hind coxae dark and metallic, mid coxa metallic with apical ¼ pale; remaining parts of legs white except tarsal claw brown. Fore wing hyaline, veins infuscate ( Fig. 5 ). Gaster brown with metallic reflections, tergite 1 with same colour as propodeum in large specimens ( Fig. 5 ), almost translucent in small specimens.

Frons with raised reticulation, antennal scrobes smooth, vertex and occiput reticulate. Head collapsed in dried specimens. Ratios of antenna: length of scape/pedicel/flagellomere 1/ flagellomere 2/clava (excl. spicule) 2.8/1.2/ 1.2/1.0/2.9; flagellomere 2 subquadrate, width of flagellomeres gradually increasing to clavomere 2, apical segment of the clava (clavomere 3) triangular. Mesosoma: ratio length/width 1.44–1.70; length of mesoscutum 0.14–0.20 mm; notauli incomplete. Pronotum and mesoscutum with raised and fine reticulation, meshes isodiametric and regular; axillae and scutellum with raised and weak reticulation, meshes a little smaller than on mesoscutum and longitudinally elongate. Scutellum ( Fig. 5 ) large and rounded: ratio length/width 0.80–0.86; submedian grooves strongly converging towards the rear and forming a trapezoidal area; ratio distance between grooves (at level of the two hind setae)/width of scutellum: 0.51–0.55. Dorsellum triangular and convex, finely reticulate and shiny. Propodeum convex in the middle but without longitudinal carina; shiny with weak reticulation that is evident everywhere; propodeal callus with 5–7 setae. Fore wing ( Fig. 5 ): ratio length/width 2.0–2.2; speculum closed below, with scattered setae on underside; basal cell open below in the proximal half; costal cell with a complete row of setae on ventral surface and with 6–9 setae on dorsal surface along distal part of the anterior margin; cubital vein strongly curved forwards to join the basal vein. Ratios submarginal/marginal/stigmal/ postmarginal veins: 3.0/2.9/1.0/1.1. Petiole inconspicuous. Shape and length of the elongate gaster very variable in dried and collapsed specimens: ratio length/width 1.4–2.4 (mean = 1.82, n = 7).

MALE. Length 1.0– 1.4 mm. Similar to the female, but with the following differences. Mesosoma metallic green with purple, violet or golden reflections. Legs with colour similar to the female but with basal ½ of hind femur infuscate in one of the small males. Marginal, postmarginal and stigmal veins of fore wing and marginal vein of hind wing yellow, very strongly enlarged ( Figs 6 , 77 ); marginal vein at least 1.2× as wide as width of costal cell at level of base of marginal vein. Gaster oval: ratio length/width 1.5–2.4 (mean = 1.83, n = 8); with a large pale median spot subbasally, occupying a large area between the second and fourth tergites ( Fig. 6 ).

Etymology. From the host plant Clematis vitalba L. (Ranunculaceae) of the agromyzid host.

Distribution. ITALY: Ceriale - Peagna, a locality in the Liguria region located on the sea coast. The first two specimens date back from 1995, 20 years later the remaining specimens were collected at the same locality and from the same host.

Host & biology. Reared from Phytomyza vitalbae Kaltenbach 1874 ( Diptera : Agromyzidae ). Attempts to obtain more specimens from the same host in other locations, nearby or distant from the type locality, or from different hosts in the type locality were without result.

This species is a larval ectoparasitoid. Males are solitary, females solitary or moderately gregarious with 2– 4 specimens in the same mine. It prefers shady and relatively cool places along dried up streams. The development period from egg to adult, at about 26–29°C, lasts two weeks. The species shares its host with four other Diglyphus species: D. isaea , D. minoeus , D. crassinervis and D. poppoea ( Table 2). In the type locality and during the summer season D. clematidis was the dominant and sometimes exclusive species obtained from P. vitalbae .

Figures

FIGURE 78. Diglyphus spp., schematic drawings of femora + tibiae from top to bottom: fore, mid and hind leg; scape + pedicel. Species are arranged according to colour of the scape, from pale to dark, and then according to colour of the legs, also from pale to dark.

FIGURES 1 – 8. Diglyphus spp., length of body, habitus in dorsal view: 1, D. albiscapus Erdös female, 1.5 mm; 2, D. albiscapus male, 1.5 mm; 3, D. anadolucus Doganlar female, 2.0 mm; 4, D. anadolucus male, 1.7 mm; 5, D. clematidis sp. nov. female holotype, 1.3 mm; 6, D. clematidis male paratype, 1.2 mm; 7, D. crassinervis Erdös female, 1.5 mm; 8, D. crassinervis male, 1.8 mm.

FIGURES 72 – 77. 72 – 73, Diglyphus spp., right fore wing, females: 72, D. chabrias (Walker); 73, D. isaea (Walker). 74 – 77, Diglyphus spp., right wing-pair, males: 74, D. anadolucus Doganlar; 75, D. crassinervis Erdös; 76, D. pachyneurus Graham; 77, D. clematidis sp. nov.