Synergus gifuensis Ashmead, 1904

Pujade-Villar, Juli, Wang, Yi-Ping, Chen, Xue-Xin & He, Jun-Hua, 2014, Taxonomic review of East Palearctic species of Synergus section I, with description of a new species from China (Hymenoptera: Cynipidae: Cynipinae), Zoological Systematics 39 (4), pp. 534-544 : 538-540

Synergus gifuensis Ashmead, 1904 ( Figs 8–11, 16, 18 )

Type material examined. Holotype ♀, deposited in USNM, with following labels: “ Y. Nawa, Gifu Japan, det 1902” (white label handwritten), “Type no 7307 USMN ” (red label), “ Synergus gifuensis & Ash. ” (white label handwritten).

Additional material. 4♂, 6♀, Chohabaru , Oita, Japan), ex. Andricus kashiwaphilus galls of the unisexual generation, (26.03.1986) May 1986, leg. Y. Abe ; 1♀, Yamanashi, Japan, June 1948, letter “A”, USNM 2017203 ( Synergus gifuensis Ashm. , det Weld-84) . 1♀, Yamanashi, Japan), June 1949, letter “A”, USNM 2017203 .

Diagnosis. The species is very similar to S. hayneanus in morphology and color, but differs from the latter by a combination of the following features: (1) presence of transverse ridges between lateral carinae of propodeum (absent in S. hayneanus ); (2) the pilosity of fused segments 2+3 with a patch of hairs, compared to a row of hairs in S. hayneanus ; (3) extended band of micropunctures of metasomal syntergite incomplete, slightly short of reaching the ventral margin (complete in S. hayeanus ); (4) the lower face with a strong median carina raised above striae in lateral view; (5) the shape of F1 and the chromatic characteristics of head in males different (details in description below). S. reinhardi is the only West Palearctic species with a strong median carina raised above striae in lateral view on lower face, but S. gifuensis differs from S. reinhardi in: (1) extended band of micropunctures of metasomal syntergite incomplete, slightly short of reaching the ventral margin (complete in S. reinhardi ); (2) pedicellum longer than broad (globose in S. reinhardi ); (3) face of males yellowish (black on S. reinhardi ); (4) radial cell short, 2.3 times as long as wide (longer in S. reinhardi , 2.6-2.8 times as long as wide).

Redescription. Length. Female 2.7–3.2 mm (one female 2.3), male 2.5–3.0 mm.

Color. Female. Head black, except a small dark-red area around the mouth and around the compound eyes, which sometimes cover the entire face; mandibles yellow with teeth dark; antennae testaceous; mesosoma black, legs dark; coxae black or dark brown; femora brown to dark brown, tibia and tarsus lighter; wings hyaline, veins clear; metasoma reddish brown to dark brown. Male. Head amberous except dorsal area black; coxae partially amberinus.

Head ( Figs 8–9 ). In frontal view 1.2 times as wide as high, and in dorsal view about twice as wide as long. Face with strong carinae radiating from clypeus and a stronger median carina distinctly elevated than other carinae in lateral view. Malar space 0.7 times the height of compound eye. Transfacial line almost as long as height of compound eye. Torulus diameter slightly greater than distance between margin of torulus and compound eye, and distance between toruli much smaller than diameter of torulus (2: 5). Frons densely punctate; lateral frontal carinae present with some ramifications near lateral ocellus. Vertex and occiput strongly punctate with interspaces coriaceous. POL: LOL: OOL= 6: 3: 3 (in males 8: 4: 3), diameter of ocellus 4 in both sexes. Gena slightly expanded behind eye, punctate with interspaces coriaceous.

Antenna. Female ( Fig. 18 ). Pedicellum about 2.0 times as long as wide; F1 cylindrical, sligthly broader distally; antennal formula 8: 5: 9: 7: 7: 7: 6: 6: 6: 5: 5: 4: 4: 6. Male ( Fig. 16 ). F1 curved and more expanded distally than basally; antennal formula 7: 5: 11: 9: 8: 8: 7: 7: 6: 6: 5: 5: 5: 5: 5.

Mesosoma ( Fig. 10 ). Subsquare in lateral view. Pronotum with lateral carina, laterally rugose, with some strongly carinae inferiorly. Mesoscutum strongly transversely carinate with interespaces coriaceous. Notauli wide, strongly impressed, percurrent; medial mesoscutum line reaching 1/2 to 3/5 of the length of the mesoscutum. Mesopleuron entirely striate. Scutellum rugose, interspaces coriaceous; scutellar foveae large and oblique, separated by a median carina, pubescent; lateral propodeal carinae straight, delimiting a squared pubescent and coriaceous area, with a median longitudinal carina and a few transverse carinae. Metanotum narrow medially.

Forewings. Pubescents. Radial cell about 2.3 times as long as maximum width. Areolet present; vein Rs curved; vein Rs+M inconspicuous.

Metasoma ( Fig. 11 ). Similar in length to mesosoma. Fused segment 2+3 not incised dorso-distally, with a patch of setae antero-laterally; apical patch of micropunctures extending to 2/5 of its entire length of metasoma, slightly short of reaching the ventral margin of syntergite; subsequent tergites punctured; hypopygium shinning, without setae or punctures. Ventral spine of hypopygium very short.

Distribution. Japan.

Biology. Abe (1990) referred to the species as Synergus japonicus type B. According to Abe, the species is univoltine and arrhenotokous, and adults emerge from unisexual galls of Andricus mukaigawae in early June and females subsequently oviposite in newly formed host galls. Galls of A. mukaigawai inhabited by S. gifuensis inquilines is larger than the same type of galls inhabited by S. japonicus , and the inquiline larval cells are usually separated by a woody wall inside the host gall (Abe, 1990, 1992; Pujade-Villar et al., 2002). In addition, specimens of this species have also been reared from the galls of the unisexual generation of Andricus kashiwaphilus (see specimen data above)

Figures

Figs 8–19. Synergus gifuensis and S. japonicus. 8–11, 16, 18. S. gifuensis. 12–15, 17, 19. S. japonicus. 8, 12. Head, dorsal view. 9, 13. Head, frontal view. 10, 14. Mesosoma, dorsal view. 11, 15. Metasoma, lateral view. 16–17. First and second flagellomeres of male antenna. 18–19. First flagellomere of female antenna.