Acraspis villosa Gillette, 1888

Nicholls, James A., Melika, George, Digweed, Scott C. & Stone, Graham N., 2022, Pairing of sexual and asexual generations of Nearctic oak gallwasps, with new synonyms and new species names (Hymenoptera: Cynipidae, Cynipini), Zootaxa 5145 (1), pp. 1-79 : 12-16

Acraspis villosa Gillette, 1888 , sexual generation

Figs 14–26, 28

Synonyms: Acraspis villosus Gillette (1888: 218) , females and galls. Acraspis villosa corrected spelling by Dalla Torre (1893: 64); Philonix villosus combination by Felt (1906: 713); Philonix villosa combination by Beutenmueller (1909: 249); Cynips (Acraspis) villosa var. villosa combination by Kinsey (1930: 355).

Kinsey (1930, 1936) described the asexual generation of six additional species within his “ villosa ” complex: Cynips (Acraspis) apache Kinsey, 1930 from Q. grisea and Q. arizonica ; Cynips (Acraspis) calvescens Kinsey, 1930 from Q. gambelii ; Cynips (Acraspis) consocians Kinsey, 1930 from Q. macrocarpa ; Cynips (Acraspis) erutor Kinsey, 1936 from Q. repanda ; Cynips (Acraspis) expletor Kinsey, 1936 from Q. oblongifolia ; and Cynips (Acraspis) expositor Kinsey, 1930 from Q. grisea . Weld (1951) and Burks (1979) treated four of these species as varieties of A. villosa ; hence Acraspis villosa var. apache (Kinsey) , syn. nov., Acraspis villosa var. calvescens (Kinsey) , syn. nov., Acraspis villosa var. consocians (Kinsey) , syn. nov., and Acraspis villosa var. expositor (Kinsey) , syn. nov. are all synonyms of A. villosa . Two species known only from Mexico are valid and treated as Cynips erutor Kinsey and C. expletor Kinsey ( Pujade-Villar & Ferrer-Suay 2015) .

Material examined: 2 sexual females labelled as “ Canada, Alberta, Edmonton, Northern Forestry Centre , 53.49165°N, - 113.54291°W, ± 10m, Collected 4.vi.2007 ex in situ mesh bag on branch of Quercus macrocarpa for rearing Acraspis villosa ♂ ♀ ”, determined originally as Acraspis villosa sexual generation females by S. Digweed, 2007. Two males labelled as “ Canada, Alberta Edmonton, NoFC, Reared 1.VI.2007, ex Quercus macrocarpa , bag for rearing. Acraspis villosa , sexual. S. Digweed ”. Specimens have been deposited at the PHDNRL and RAM .

Diagnosis. Closely resembles Acraspis gemula (Bassett, 1881) and A. quercushirta . In A. villosa notauli are incomplete, entire body dark brown to black. In A. gemula notauli are complete, entire body reddish brown. See also Diagnosis to A. quercushirta .

Description. Sexual female ( Figs 14–17 , 22–26 ). Head, mesosoma, metasoma uniformly dark brown to black; scapus, pedicel, F1 light brown, subsequent flagellomeres darker, slightly lighter than body; mouthparts and legs light brown to yellowish.

Head alutaceous, with white setae, denser on lower face and postgena, rounded, 1.2× as broad as high and as broad as mesosoma in frontal view,1.6x as broad as long from dorsal view. Gena alutaceous, not broadened behind eye in frontal view, narrower than transverse diameter of eye in lateral view. Malar space alutaceous, glabrous, without striae; eye 2.5× as high as length of malar space. Inner margins of eyes parallel. POL 1.8× as long as OOL, OOL 1.75× as long as diameter of lateral ocellus and 1.2× as long as LOL, all ocelli small, ovate, of same size. Transfacial distance 1.2× as long as height of eye; diameter of antennal torulus 1.9× as long as distance between them, distance between torulus and eye 1.3× as long as diameter of torulus; lower face alutaceous, matte, with dense white setae, slightly elevated median area alutaceous. Clypeus rectangular, nearly 2.0× as broad as high, smooth, matte, with long setae; ventrally rounded, slightly emarginate, without median incision; anterior tentorial pit small, rounded, epistomal sulcus distinct, clypeo-pleurostomal line well impressed. Frons and interocellar area uniformly alutaceous, without striae or setae. Vertex, occiput and postocciput alutaceous; postgena smooth, glabrous, with dense white setae; posterior tentorial pit small, rounded, area below impressed; occipital foramen greater than 2.0× as high as height of postgenal bridge; hypostomal carina emarginate, continuing into postgenal sulci which diverge toward occipital foramen, postgenal bridge anteriorly as broad as occipital foramen. Antenna longer than head+mesosoma, nearly as long as body, with 12 flagellomeres, pedicel slightly longer than broad, flagellomeres slightly broader towards apex; F1 2.5× as long as pedicel and 1.3× as long as F2; F2 slightly longer than F3; F3 1.1× as long as F4, F5 slightly longer than F6, all subsequent flagellomeres equal in length; placodeal sensilla on F2–F12, absent on F1.

Mesosoma 1.2× as long as high, with sparse white setae, except for dense setae on lateral propodeal area.Pronotum smooth, matte, with sparse setae, without striae laterally; propleuron alutaceous, matte. Mesoscutum smooth, glabrous, with sparse white setae, slightly longer than broad (greatest width measured across mesoscutum level with base of tegulae). Notaulus incomplete, extending to 2/3 of mesoscutum length, shallow, broad, bottom smooth, glabrous, posteriorly broader and slightly converging; anterior parallel line, parapsidal line, median mesoscutal line absent; circumscutellar carina narrow, distinct, reaching notaulus. Mesoscutellum ovate, slightly longer than broad, with semi-parallel sides, coriaceous, overhanging metanotum, posteriorly rounded. Mesoscutellar foveae absent, anterior part of mesoscutellum is not impressed, in the same plane as mesoscutellar disk, with the same sculpture as the entire mesoscutellum. Mesopleuron smooth, matte, setae only on posteroventral quarter of mesopleuron; mesopleural triangle delicately coriaceous, matte, with some delicate longitudinal parallel striae and a few setae; dorsal and lateral axillar areas smooth, glabrous, with a few setae; subaxillular bar smooth, glabrous, triangulate, gradually higher toward posterior end, at posterior end as high as height of metanotal trough; metapleural sulcus reaching mesopleuron slightly below half of its height, upper part of sulcus indistinct. Metascutellum coriaceous, as high as height of coriaceous ventral impressed area; metanotal trough smooth, matte, without setae; central propodeal area lyre-shaped, rugose, matte, with few rugae in posterior half which continue onto nucha; lateral propodeal carinae bent slightly outwards in posterior 1/3, complete or incomplete, do not reach anterior end of propodeum; lateral propodeal area coriaceous, matte, with long white setae. Nucha with net of irregular rugae dorsally and laterally. Tarsal claws with small basal lobe.

Forewing longer than body, hyaline, with distinct dense cilia on margin, veins brown, radial cell open, 5.0× as long as broad; R1 and Rs reaching wing margin; areolet large, triangular, closed, distinct. Rs+M distinct, reaching basalis slightly below its mid height.

Metasoma slightly longer than head+mesosoma, longer than high in lateral view; 2nd metasomal tergum extending to half length of metasoma in dorsal view, with sparse scattered setae laterally; all terga alutaceous, matte, without micropunctures. Hypopygium without micropunctures, prominent part of ventral spine of hypopygium longer than broad in ventral view, with some short setae ventrally which extend beyond apex of spine. Body length 1.8 mm (n = 1).

Male ( Figs 18–21 ). Similar to female, head, mesosoma and metasoma black to dark brown, mandibles and palpi maxillaris and labialis light brown, antenna brown; legs uniformly light brown to yellow. Eye 3.3× as high as length of malar space; ocelli much bigger than in female. Antenna as long as body, forewing longer than body; metasoma slightly shorter than mesosoma. Antenna with 13 flagellomeres, scapus+pedicel shorter than F1; F1 slightly curved, excavated, apically broadened, 1.2× as long as F2; F13 longer than F12; placodeal sensilla on all flagellomeres. Metasoma with long narrow petiole, 2nd metasomal tergum extending to half length of metasoma, with a few white setae laterally; all terga smooth, glabrous, without micropunctures.

Gall ( Fig. 28 ). The sexual galls are not apparently distinguishable from galls of the sexual generation of Acraspis quercushirta , described above.

Biology. See Weld (1926) and Kinsey (1930, 1936) for the biology of the asexual generation. Asexual galls ( Fig. 27 ) from species in Kinsey’s (1936) “ villosa ” complex have been recorded on leaves of Q. alba , Q. arizonica , Q. gambelii , Q. grisea , Q. macrocarpa and Q. oblongifolia . Adult females of the asexual generation emerged (from galls collected in Manitoba but reared in Edmonton) during the second half of October and early November. Adults of the sexual generation emerged in Edmonton from late May to early June. Galls of the asexual generation appeared on leaves in Edmonton in July.

Distribution. USA: New York, Michigan, Iowa, Kansas, Texas, Utah, Arizona ( Burks 1979); Canada: Manitoba.

Molecular taxonomy. Alternate sexual and asexual generations were proposed by Digweed (2010) and are herein matched using DNA data, with four individuals (two asexual females, two sexual females) sequenced for both cytb and ITS2. Cytb haplotype sequences were identical among the four individuals (GenBank accessions MW388885 , OM321613 – OM321615 ), as were ITS2 sequences ( OM331806 – OM331809 ).

Figures

FIGURES 14–21. Acraspis villosa Gillette, sexual generation. 14–17, head, female: 14, frontal view, 15, dorsal view, 16, posterior view, 17, lateral view. 18–21, head, male: 18, frontal view, 19, dorsal view, 20, posterior view, 21, lateral view.

FIGURES 22–25. Acraspis villosa Gillette, sexual generation, female. 22, antenna. 23, pronotum and propleuron, frontal view. 24, mesosoma, dorsal view. 25, metascutellum and propodeum, posterodorsal view.

FIGURES 26–28. Acraspis villosa Gillette. 26, forewing, part, sexual female. 27, asexual gall. 28, sexual gall.