Andricus schickae Nicholls, Melika & Stone, 2021

Melika, George, Nicholls, James A., Abrahamson, Warren G., Buss, Eileen A. & Stone, Graham N., 2021, New species of Nearctic oak gall wasps (Hymenoptera: Cynipidae, Cynipini), Zootaxa 5084 (1), pp. 1-131 : 59-66

Andricus schickae Nicholls, Melika & Stone , sp. nov.

Figs. 205–234

urn:lsid:zoobank.org:act:09D4D2BC-2321-4342-BA4A-F1D2A5E9BAE4

Alternate asexual and sexual generations are described.

Etymology. Named after Dr. Katherine Northup Schick (San Joaquin Delta College and Essig Museum, UC Berkeley) in recognition of her contributions to Nearctic gall wasp research.

Sexual generation

Type material: HOLOTYPE female “ USA, California, Los Molinos, leg. J. Nicholls. 2008.03.30. Code CA1080 , spCAl5; ex Quercus lobata ” . PARATYPES: 4 females and 5 males: 3 females and 4 males with the same labels as the holotype; 1 female and 1 male “ USA, California, Delta College , Stockton. Leg. J. Nicholls. 2008.03.28. Code CA1076 ; ex Quercus lobata ”. The holotype and one male are deposited at the USNM , 4 females and 4 males at the PHDNRL .

Diagnosis. No other sexual generations of Andricus species from California are known to induce unilocular integral leaf galls that are simply swellings of the petiole/midrib.

Description. Sexual female ( Figs. 205–207, 210 , 213–218 ). Head and mesosoma black, metasoma dark brown, antennae brown, flagellomeres gradually darker towards the apex; mandibles and mouthparts light brown, legs light brown to yellow.

Head alutaceous to delicately coriaceous, with sparse white setae, denser on lower face, 1.2× as broad as high and slightly broader than mesosoma in frontal view, 2.1× as broad as long in dorsal view. Gena coriaceous, not broadened behind eye in frontal view, narrower than transverse diameter of eye in lateral view. Malar space coriaceous, with numerous striae radiating from clypeus and reaching eye; eye 2.6× as high as length of malar space. Inner margins of eyes converging ventrally. POL 2.5× as long as OOL; OOL 1.9× as long as diameter of lateral ocellus and shorter than LOL; all ocelli ovate, of same size. Transfacial distance 1.2× as long as height of eye; diameter of antennal torulus 1.3× as long as distance between them, distance between torulus and inner margin of eye 1.2× as long as diameter of torulus; lower face coriaceous, with dense white setae and striae radiating from clypeus and extending into area between antennal torulus and eye; slightly elevated median area coriaceous, without striae, with a few short setae. Clypeus small, rectangular, broader than high, smooth, glabrous, with a few long setae; ventrally rounded, not emarginate, without median incision; anterior tentorial pit large, rounded, epistomal sulcus and clypeopleurostomal line broad, well impressed. Frons and slightly elevated interocellar area alutaceous, without striae, with a few short white setae. Vertex, occiput delicately coriaceous, with sparse white setae; postocciput, postgena smooth, glabrous, posterior tentorial pit large, ovate, area below impressed; occipital foramen as long as height of postgenal bridge; hypostomal carina emarginate, continuing into united postgenal sulci which run together at 2/3 of postgenal bridge height; in anterior 1/3 sulci diverge towards occipital foramen, postgenal bridge in anterior 1/3 as broad as occipital foramen. Antenna longer than head+mesosoma, with 12 flagellomeres (suture between F12 and F11 indistinct but traceable), pedicel subglobular; F1 2.2× as long as pedicel; F1=F2=F3; F3 1.3× as long as F4; subsequent flagellomeres shorter, nearly equal in length; placodeal sensilla hardly distinguishable.

Mesosoma longer than high, with sparse short white setae. Pronotum smooth glabrous, with delicate striae laterally; propleuron smooth, glabrous. Mesoscutum uniformly alutaceous, without setae; slightly longer than broad (greatest width measured across mesoscutum at level of base of tegulae). Notaulus complete, deep, with smooth, glabrous bottom, posteriorly converging; anterior parallel and parapsidal lines indistinct, hardly traceable, marked by smooth glabrous areas; median mesoscutal line in the form of a short triangle; circumscutellar carina narrow, reaching notauli. Mesoscutellum longer than broad, with parallel sides, posteriorly rounded, uniformly rugose, overhanging metanotum. Mesoscutellar foveae transverse, 3.0× as broad as high, separated by narrow triangular elevated coriaceous central carina, with smooth, glabrous bottom. Mesopleuron and speculum uniformly smooth, glabrous, with delicate transverse parallel striae at mid height that run across mesopleuron, with some setae ventrally; mesopleural triangle smooth, glabrous, with a few white setae; dorsal and lateral axillar areas smooth, glabrous, with a few white short setae; subaxillular bar smooth, glabrous, triangular, posterior end as high as height of metanotal trough; metapleural sulcus reaching mesopleuron slightly above mid height, upper part of sulcus distinct. Metascutellum coriaceous, slightly higher than height of smooth, glabrous ventral impressed area; metanotal trough coriaceous, glabrous, with few setae; central propodeal area smooth, glabrous, with a few irregular short rugae, lyreshaped; lateral propodeal carinae bent outwards in posterior 1/4; lateral propodeal area coriaceous, glabrous, with long white setae. Nucha with numerous delicate sulci dorsally and laterally. Tarsal claws toothed, with basal lobe.

Forewing longer than body, hyaline, margin with long dense cilia, veins dark brown, radial cell open, 5.4× as long as broad; R1 and Rs nearly reaching wing margin; areolet triangular, well-delimited, Rs+M distinct for half the distance to basalis, its projection reaching basalis in lower half.

Metasoma longer than head+mesosoma, longer than high in lateral view; second metasomal tergite extending to 1/3 of metasoma length in dorsal view, with dense white setae anterolaterally; all tergites smooth, glabrous, without micropunctures. Hypopygium without micropunctures, prominent part of ventral spine of hypopygium 4.25× as long as broad in ventral view, with some short setae ventrally, some of which extend beyond apex of spine.

Body length 1.9–2.3 mm (n = 5).

Male ( Figs. 208–209, 211 , 219 ). Similar to female but metasoma black, transfacial distance as long as height of eye, eye 3.5× as high as length of malar space, POL 2.4× as long as OOL, OOL equal in length to diameter of lateral ocellus and 1.4× as long as LOL; ocelli larger, ovate; interocellar area elevated; antenna with 13 flagellomeres, F1 straight, apically not swollen, F13 shorter than F12; placodeal sensilla on all flagellomeres. Body length 1.9–2.1 mm (n = 4).

Gall. ( Figs. 233–234 ). A unilocular integral gall in the leaf midrib or petiole, 3–4 mm long by ca. 2 mm across, visible as a slight longitudinal swelling that is a paler yellow-green than the rest of the leaf, sometimes also reddish. The gall causes distortion of the leaf lamina, in some cases bending it back through almost 180°.

Asexual generation

Material examined: 5 females: 2 females “ Canada, Upland Park , Victoria, leg. J. Nicholls, 2007.11.15. Code BC190, ex Quercus garryana ” and 3 females “ Canada, Summit Park , Victoria, leg. J. Nicholls, 2007.11.14. Code BC214, spBCb2; ex Quercus garryana ”. All specimens are deposited at the PHDNRL .

Diagnosis. Galls closely resemble those of Andricus occultatus , but the adults are different. Andricus occultatus females are black, with the antenna, legs, and ventral spine of hypopygium yellow; malar space longer; antenna with 11 flagellomeres, F2-F7 equal in length, F8=F9; the mesoscutum with dense setae, hidden coriaceous sculpture; second metasomal tergite with only a few short sparse setae anterolaterally; the prominent part of the ventral spine of hypopygium is short, only 3.0× as long as broad in ventral view. Also closely resembles A. columbiensis . However, in asexual A. schickae the inner margins of eyes converging ventrally, OOL 2.0× as long as diameter of lateral ocellus, the transfacial distance longer than height of eye, the clypeus small, trapezoid, slightly broader than high, the mesoscutum uniformly alutaceous, the median mesoscutal line in the form of a short triangle, the radial cell of the forewing 4.5× as long as broad, the hypopygium with micropunctures, the prominent part of the ventral spine of the hypopygium more than 10.0× as long as broad in ventral view, without setae; while in A. columbiensis the inner margins of eyes parallel, OOL 1.3× as long as diameter of lateral ocellus, the transfacial distance as long as height of eye, the clypeus quadrangular, nearly as high as broad, the mesoscutum coriaceous, the median mesoscutal line extends to 1/3 of the mesoscutum length, the radial cell of the forewing 3.5× as long as broad, the hypopygium without micropunctures, the prominent part of the ventral spine of the hypopygium 6.0× as long as broad in ventral view, with a few setae ventrally which do not extend beyond apex of spine.

Description. Asexual female ( Figs. 220–231 ). Head, antennae and mesosoma dark brown, metasoma lighter; mandibles and mouthparts light brown, legs brown.

Head alutaceous to delicately coriaceous, with sparse white setae, denser on lower face and postgena, 1.2× as broad as high and slightly broader than mesosoma in frontal view, 2.3× as broad as long in dorsal view. Gena alutaceous, broadened behind eye in frontal view, broader than transverse diameter of eye in lateral view. Malar space coriaceous, with numerous striae radiating from clypeus and reaching eye; eye 2.2× as high as length of malar space. Inner margins of eyes converging ventrally. POL 2.3× as long as OOL; OOL 2.0× as long as diameter of lateral ocellus and shorter than LOL; all ocelli nearly rounded, of same size. Transfacial distance 1.2× as long as height of eye; diameter of antennal torulus 1.2× as long as distance between them, distance between torulus and inner margin of eye 1.5× as long as diameter of torulus; lower face coriaceous, with dense white setae and striae radiating from clypeus and extending into area between antennal torulus and eye; slightly elevated median area coriaceous, without striae, with a few short setae. Clypeus small, trapezoid, slightly broader than high, smooth, glabrous, with a few long setae; ventrally rounded, not emarginate, without median incision; anterior tentorial pit small, rounded, epistomal sulcus and clypeo-pleurostomal line indistinct. Frons and slightly elevated interocellar area alutaceous, without striae, with a few short white setae. Vertex alutaceous, occiput with delicately transverse parallel striae, with sparse white setae; postocciput, postgena smooth, glabrous, with dense setae; posterior tentorial pit large, ovate, area below impressed; occipital foramen slightly higher than height of postgenal bridge; hypostomal carina emarginate, continuing into postgenal sulci which are not united, running parallel in ventral 2/3 of postgenal bridge, diverge in anterior 1/3, postgenal bridge anteriorly as broad as occipital foramen. Antenna longer than head+mesosoma, with 12 flagellomeres, pedicel longer than broad; F1 1.9× as long as pedicel, F1=F2, F2 1.25× as long as F3, F3=F4=F5, subsequent flagellomeres shorter, nearly equal in length, F12 slightly longer than F11, placodeal sensilla on F2–F12.

Mesosoma longer than high, with sparse short white setae. Pronotum smooth and glabrous, with delicate striae laterally; propleuron smooth, glabrous. Mesoscutum uniformly alutaceous, with dense setae along notauli and in anterior 1/3; slightly longer than broad (greatest width measured across mesoscutum at level of base of tegulae). Notaulus complete, deep, with smooth, glabrous bottom, posteriorly converging; anterior parallel and parapsidal lines indistinct, hardly traceable, marked by smooth glabrous areas; median mesoscutal line in the form of a short triangle; circumscutellar carina narrow, reaching notauli. Mesoscutellum slightly longer than broad, trapezoid, with subparallel sides, slightly broadened in posterior 1/3; posteriorly rounded, uniformly rugose, overhanging metanotum. Mesoscutellar foveae transverse, 2.0× as broad as high, with smooth, glabrous bottom, separated by narrow triangular elevated coriaceous central carina. Mesopleuron glabrous, with delicate transverse parallel striae in anteromedian part, with some setae ventrally; speculum uniformly smooth, glabrous; mesopleural triangle smooth, glabrous, with white setae; dorsal and lateral axillar areas smooth, glabrous, with a few white short setae; subaxillular bar smooth, glabrous, triangular, posterior end as high as height of metanotal trough; metapleural sulcus delimiting area with dense setae, reaching mesopleuron slightly below mid height, upper part of sulcus distinct. Metascutellum coriaceous, glabrous, as high as height of smooth, glabrous ventral impressed area; metanotal trough smooth, glabrous, with few setae; central propodeal area smooth, glabrous, without rugae and setae, lyre-shaped; lateral propodeal carinae bent outwards in posterior 1/4; lateral propodeal area smooth, glabrous, with long white dense setae. Nucha with numerous delicate sulci dorsally and laterally. Tarsal claws toothed, with basal lobe.

Forewing longer than body, hyaline, margin with long dense cilia, veins light brown, radial cell open, 4.5× as long as broad; R1 and Rs nearly reaching wing margin; areolet triangular, well-delimited, Rs+M distinct on 1/3 of distance to basalis, its projection reaching basalis in lower half.

Metasoma slightly longer than head+mesosoma, as long as high in lateral view; second metasomal tergite extending to half the length of metasoma in dorsal view, with felt-like dense ring of setae anterolaterally, without micropunctures posteriorly; subsequent tergites smooth, glabrous, with sparse micropunctures. Hypopygium with micropunctures, prominent part of ventral spine of hypopygium greater than 10.0× as long as broad in ventral view, without setae. Body length 2.3–2.6 mm (n = 5).

Gall. ( Fig. 232 ). A cryptic unilocular gall within a swollen terminal or lateral bud, whose scales remain intact and surround the gall. The gall is ca. 2–2.5 mm long and 1–1.5 mm in diameter, and consists only of the larval chamber, with a thin woody wall.

Biology. Alternate asexual and sexual generations are known. The asexual generation bud galls develop on Q. garryana , mature in November, adults emerge the following spring. The sexual generation galls ( Figs. 233–234 ) were found on Q. lobata leaves in late March-April; adults emerge soon afterwards. We expect both generations can be found on both Q. lobata and Q. garryana .

Generations were matched using DNA data, with nine individuals (seven asexual females, one sexual female, one sexual male) sequenced for both cytb and ITS2. Cytb sequences were between 0 and 1.62% divergent (GenBank OK346283 – OK346291 ); ITS2 sequences were between 0 and 0.20% divergent (with two additional insertions/ deletions in the ITS data; OK350646 – OK350654 ).

Distribution. USA, California (Los Molinos, Stockton, Cosumnes River Preserve) and Canada, British Columbia (Victoria).

Figures

FIGURES 205–212. Andricus schickae Nicholls, Melika & Stone, sp. nov., sexual generation. 205–207, head, female: 205, frontal view, 206, dorsal view, 207, posterior view. 208–209, head, male: 208, frontal view, 209, dorsal view. 210–211, antenna: 210, female, 211, male. 212, forewing, female.

FIGURES 213–219. Andricus schickae Nicholls, Melika & Stone, sp. nov., sexual generation. 213–217, female:213, mesosoma and propleura, frontal view, 214–216, mesosoma: 214, lateral view, 215–216, dorsal view, 217, metascutellum and propodeum, posterodorsal view. 218–219, metasoma, lateral view: 218, female, 219, male.

FIGURES 220–226. Andricus schickae Nicholls, Melika & Stone, sp. nov., asexual generation, female. 220–223, head: 220, frontal view, 221, dorsal view, 222, lateral view, 223, posterior view. 224, antenna, 225, mesosoma and propleura, frontal view, 226, metascutellum and propodeum, posterodorsal view.

FIGURES 227–231. Andricus schickae Nicholls, Melika & Stone, sp. nov., asexual generation, female. 227–229, mesosoma: 227–228, dorsal view, 229, lateral view. 230, forewing, part, 231, metasoma, lateral view.

FIGURES 232–234. Andricus schickae Nicholls, Melika & Stone, sp. nov., galls: 232, asexual generation, 233–234, sexual generation.