Synergus erinacei Gillette, 1896

Lobato-Vila, Irene & Pujade-Villar, Juli, 2021, The genus Synergus Hartig (Hymenoptera: Cynipidae: Synergini) in the New World: a complete taxonomic revision with a key to species, Zootaxa 4906 (1), pp. 1-121 : 51-53

Synergus erinacei Gillette, 1896

( Figure 19 )

Synergus erinacei Gillette, 1896 . Trans. Am. Entomol. Soc. 23: 90, 94. Type material: USNM.

Type material (examined). LECTOTYPE ♀ with the following labels: ‘N. Y. 2008’ (white label, handwritten) / ‘ Type’ (white label, handwritten) / ‘ Type No. 27943 U.S. N.M.’ (red label) / ‘ AccNo 71950 USNM to be loaned only to ColoAgCol’ (white label) / ‘ Synergus erinacei n. sp. C.P. G’ (white label with a red frame, handwritten) / ‘ USNMENT 00802049 ’ (white label with a QR code) / ‘ Lectotype ♀ Synergus erinacei Gillette, 1896 , IL-V desig-2017’ (red label). PARALECTOTYPES (1♂ & 6♀) with the following labels: ‘N. Y. 2008’ (white label, handwritten) / ‘Type’ (white label, handwritten) / ‘Collection Ashmead’ (white label) / ‘ Paratype No. 27943 U.S. N.M.’ (red label) / ‘ Synergus erinacei Gill. ♀ ’ (white label, handwritten) / ‘ Paralectotype ♀ Synergus erinacei Gillette, 1896 , IL-V desig-2017’ (red label) (2♀); ‘Ia. Exp. Sta.’ (white label) / ‘Type’ (white label, handwritten) / ‘ Paratype No. 27943 U.S. N.M.’ (red label) / ‘ AccNo 71950 USNM to be loaned only to ColoAgCol’ (white label) / ‘ Paralectotype ♀ Synergus erinacei Gillette, 1896 , IL-V desig-2017’ (red label) (1♀); ‘N. Y. 1726’ (white label, handwritten) / ‘Type’ (white label, handwritten) / ‘Coll CF Baker’ (white label) / ‘ Synergus erinacei Gill. ’ (red label with a black frame, handwritten) / ‘USNMENT 00960173’ (white label, QR code) / ‘ Paralectotype Synergus erinacei Gillette, 1896 , IL-V desig-2017’ (red label) (1♂ & 3♀)

Other material examined (3♀). Material deposited in USNM with the following labels: ‘Evanston Ill. 8/23/14’ (white label) / ‘ Ovopositing in Hedgehog Gall’ (white label) / ‘ Synergus erinacei Gill. ’ (white label with a black frame, handwritten) (1♀) ; ‘ W.W. Judd, oak gall, London, Ontario 99, 31.viii.1967 ’ (white label) / ‘B8’ (white label, handwritten) / ‘ Acraspis erinacei ’ (white label, handwritten) (1♀) ; ‘ W.W. Judd, oak gall, London, Ontario 83, 3.ix.1967 ’ (white label) / ‘B10’ (white label, handwritten) / ‘ Acraspis erinacei ’ (white label, handwritten) (1♀) .

Diagnosis. Synergus erinacei belongs to a group of species characterized by having the mesopleuron entirely sculptured, covered with parallel and fine transverse striae; hyaline wings and radial cell of fore wing at most 2.5 times as long as wide; POL longer than OOL; gena usually not broadened behind eye (slightly broadened in S. erinacei ); F1 as long as F2 and female antenna with 14 segments; lateral pronotum wrinkled or carinated, at least ventrally; mesoscutum with transversal carinae, interspaces sculptured, rarely strongly coriaceous with weak discontinuous transversal elements; notauli complete, reaching the posterior margin of pronotum; tarsal claws with a distinct basal lobe; first metasomal segment completely sulcate dorsally and laterally; syntergum with a posterior band of micropunctures; and body of females with some dark surfaces, never completely yellow. Synergus erinacei differs from the species sharing these traits ( S. nigroornatus , S. oneratus and S. rutulus , see below) by having mesosoma and metasoma entirely black in females ( Fig. 19 a–b) (mostly yellow, dark yellow or reddish yellow in females of these species, Figs 25a, c ; 30 a–g, j; 37a–b); gena slightly broadened behind eye ( Fig. 19c ) (not broadened in these species); and OOL about 1.7 times as long as diameter of lateral ocelli in females, equal in males (1.2 or 1.3 in both sexes of these species), among others (see the identification key).

Redescription

FEMALE. Length. Body length about 3.0 mm (n = 7).

Color ( Fig. 19 ). Mainly black. Gena and lower face, yellow; frons and vertex medially, and occiput, black. Antenna yellow to testaceous. Mesosoma black; tegulae yellow. Metasoma black. Legs pale yellow. Wings hyaline, veins light brown to yellow.

Head. In frontal view ( Fig. 19c ) trapezoid, about 1.2 times as wide as high, gena very slightly broadened behind eye. Face faintly pubescent, lower face with striae radiating from clypeus. Clypeus indistinct, ventral margin straight, not projected over mandibles. Malar space about 0.5 times as long as height of eye. Anterior tentorial pits visible; pleurostomal and epistomal sulcus absent. Transfacial line about as long as height of eye. Toruli situated mid-height of eye; distance between torulus and eye shorter than diameter of torulus; distance between toruli shorter than diameter of toruli. Frons coriaceous, without punctures; frontal carinae narrow and branched, reaching lateral ocelli. Head in dorsal view is about 2.0 times as wide as long. Vertex coriaceous, with some punctures. POL: OOL: LOL = 10: 7.5: 5 and diameter of lateral ocelli, 4.5. Occiput coriaceous, with some punctures.

Antenna ( Fig. 19b ). 14-segmented; filiform, not broadened apically, and as long as the entire body; pubescence dense and short. Scape plus pedicel about as long as F1 or just slightly longer; pedicel about 1.8 times as long as wide; F1 as long as F2, F2 and F3 subequal; the following segments progressively shorter. Last flagellar segment about 3.5 times as long as wide and almost 2.0 times as long as F11.

Mesosoma. About 1.2 times as long as high in lateral view, including nucha, with short and not dense pubescence ( Fig. 19a ). Ratio of length of pronotum medially/laterally: 0.36. Pronotal plate indistinct. Lateral pronotum imbricated to weakly wrinkled; lateral carina absent, lateral margins of pronotum rounded seen from above. Mesoscutum ( Fig. 19b ) about 1.2 times as wide as long, strongly coriaceous with weak discontinuous transversal elements; anterior parallel lines weakly impressed, reaching somewhat more than 1/3 of the mesoscutum; notauli complete and visible in their whole length, but less impressed anteriorly; median mesoscutal line absent; parapsidal lines weakly impressed, narrow, reaching tegulae. Mesoscutellum ( Fig. 19b ) about 1.1 times as long as wide, wrinkled; circumscutellar carina weak, almost inconspicuous, obscured by wrinkles; scutellar foveae circular, small, shallow, weakly sculptured bottom, the posterior margin not well defined and separated by a narrow carina. Mesopleuron regularly striated, somewhat branched anteriorly. Metapleural sulcus reaching almost 3/4 of mesopleural height. Propodeum pubescent and weakly sculptured; propodeal carinae straight and parallel. Nucha sulcate dorsally and laterally.

Legs. Tarsal claws with a very strong basal lobe.

Wings. Fore wing pubescent with short marginal setae, about as long as the body length ( Fig. 19a ). Radial cell closed, about 2.4 times as long as wide; areolet visible, all veins well pigmented but pale. Rs+M visible, not reaching the basal vein. Basal cell with sparsely spaced setae.

Metasoma. About as long as head plus mesosoma and about 1.3 times as long as high in lateral view ( Fig. 19a ). First metasomal segment sulcate dorsally and laterally. Syntergum smooth, anterolateral pubescence composed of a few setae and posteriorly with a band of micropunctures extended about 1/4 of its length; not dorsodistally incised, slightly pointed. Hypopygial spine about as long as wide and with a few lateral setae; without apical setae.

MALE. Similar to female, except for the following: body length about 1.5 mm (n = 1). Antenna 15-segmented according to the original description (antennae of the single examined male are broken). POL:OOL:LOL = 19:10:9.5. OOL about as long as diameter of lateral ocelli. Malar space 0.6 times as long as height of eye. Metasoma shorter than head plus mesosoma, the band of micropunctures extended at least 1/2 of the syntergum length. Head yellow, except for a black spot in the ocellar area.

Distribution. USA: New York, Iowa ( Gillette 1896), and Illinois (authors). Also, in Canada: Ontario (authors).

Biology. Reared from galls of Acraspis erinacei (Beutenmüller, 1909) ( Gillette 1896; authors).

Remarks. Synergus erinacei was described from 2♂ and 14♀ ( Gillette 1896: 94). We located and examined 1♂ and 7♀ belonging to the type series deposited in USNM. A lectotype has herein been designated.

The host plant is not mentioned in the original description, but A. erinacei produces bud galls (sexual generation) and leaf galls (agamic) on Q. alba ( Burks 1979: 1078) .

Figures

FIGURE 19. Synergus erinacei (lectotype, USNMENT 00802049): a) lateral habitus; b) dorsal habitus; c) head in frontal view.

FIGURE 25. Synergus nigroornatus (lectotype, Type No. 5804): a) lateral habitus; b) lateral metasoma; c) mesosoma in dorsal view; d) head in anterodorsal view.

FIGURE 30. Synergus oneratus. Lectotype of Cynips oneratus (MCZ-ENT 00026335): a) lateral habitus; b) detailed view of the lateral pronotum and mesoscutum; c) head and pronotum in anterodorsal view; d) dorsal habitus. Lectotype of Synergus oneratus coloradensis (USNMENT 00779991): e) lateral habitus; f) mesosoma in dorsal view. Lectotype of Synergus garryana (USNMENT 00802113): g) lateral habitus; h) detailed view of the metasomal punctuation; i) head in anterodorsal view; j) mesosoma in dorsal view.