Dryocosmus castanopsidis ( Beutenmueller, 1917 )

Nicholls, James A., Melika, George & Stone, Graham N., 2018, New species of Dryocosmus Giraud gallwasps from California (Hymenoptera: Cynipidae: Cynipini) galling Chrysolepis Hjelmq. (Fagaceae), Zootaxa 4532 (3), pp. 407-433 : 424-425

Dryocosmus castanopsidis ( Beutenmueller, 1917)

Figs 86–99

Material examined. 3 females labelled as “ USA, California, Lassen Volcanic National Park , leg. J. DeMartini, coll. 2012.09.24, ex Chrysolepis sempervirens ( CA1317 )” ; 1 female labelled as “USA, California, 30 km E of Arcata , leg. J. Nicholls, coll. 2008.09.26 ex Chrysolepis chrysophylla ( CA1208 )”. Specimens are deposited in the collection of PHMB (Budapest, Hungary) .

Diagnosis. See the Diagnosis to D. demartinii , new species and the key to species.

The original description of the species ( Beutenmueller 1917) is short and incomplete. Therefore we provide a detailed description of the asexual female below.

Description. Asexual female ( Figs 86–96 ). Body, antennae, mouthparts, legs uniformly reddish brown.

Head coriaceous, with sparse white setae, denser on lower face, vertex, occiput, postocciput; 2.2x broader than long in dorsal view; 1.3x broader than high in anterior view and slightly broader than mesosoma. Gena alutaceous, broadened behind eye in dorsal view; as broad as diameter of eye in lateral view. Malar space alutaceous, without striae radiating from clypeus; eye 2.2x higher than length of malar space. Inner margins of eyes parallel. POL 1.6x longer than OOL; OOL 1.8x longer than diameter of lateral ocellus, 1.3x longer than LOL; ocelli ovate, all equal in size. Transfacial distance 1.4x longer than height of eye and 1.5x longer than height of lower face (distance between antennal rim and ventral margin of clypeus); diameter of antennal torulus 1.5x longer than distance between them, distance between torulus and eye margin 1.4x longer than diameter of torulus. Lower face delicately coriaceous, with white setae, without striae radiating from clypeus, median area not elevated. Clypeus trapezoid, flat, broader than high, alutaceous, with deep anterior tentorial pits, distinct epistomal sulcus and clypeopleurostomal line; ventrally straight, not emarginate, not incised medially, with dense long setae reaching far beyond ventral margin of clypeus. Frons delicately coriaceous, with rare short setae; vertex, interocellar area, occiput are delicately coriaceous with rare short white setae. Postgena coriaceous, glabrous, with dense setae, postocciput around occipital foramen impressed, smooth, glabrous, without striae along occiput; posterior tentorial pits large, deep, elongate; postgenal bridge narrowed to a strip, at least 2.0x higher than broad; occipital foramen higher than height of postgenal bridge, 2.5x shorter than height of oral foramen. Antenna with 12 flagellomeres, longer than head+mesosoma; pedicel 1.4x longer than broad, F1 as long as length of scape+pedicel, equal in length to F2, F2 1.3x longer than F3, F3=F4 and slightly longer than F5, subsequent flagellomeres nearly equal in length; placodeal sensilla very indistinct on all flagellomeres.

Mesosoma longer than high in lateral view. Pronotum smooth, glabrous; with white setae and without striae laterally; emarginate along lateral edge, followed by deep longitudinal invagination. Anterior rim of pronotum narrow, emarginate; propleuron alutaceous, with few setae, strongly concave in mediocentral part. Mesoscutum smooth, glabrous between notauli, alutaceous lateral to notaulus; longer than broad (width measured across base of tegulae); notauli complete, deeply impressed for full length; median mesoscutal line distinct, broad, reaching to 1/ 10 of mesoscutum length; anterior parallel lines invisible; parapsidal lines broad, reaching about 2/3 of the length of mesoscutum; parascutal carina broad, anteriorly reaching notaulus. Transscutal articulation deep, distinct, straight. Mesoscutellum only slightly longer than broad, with subparallel sides, only slightly broader posteriorly; shorter than mesoscutum, uniformly rugose, overhanging metanotum; scutellar foveae transversely ovate, with glabrous, smooth bottom, divided by narrow central elevated area. Mesopleuron smooth, glabrous, with a few white setae along ventral and anterior margins; speculum smooth, glabrous; mesopleural triangle coriaceous, glabrous, with dense white setae. Metapleural sulcus reaching mesopleuron slightly above half its height; preaxilla coriaceous, glabrous; dorsal and lateral axillar areas glabrous, alutaceous, with few setae; axillar carina broad, with longitudinal striae; subaxillular bar narrow, smooth, glabrous, at posterior end 2.0x shorter than the height of metanotal trough. Metascutellum coriaceous, slightly higher than height of smooth, glabrous ventral impressed area; metanotal trough smooth, glabrous, with dense white setae. Lateral propodeal carinae distinct, sub-parallel, central propodeal area smooth, glabrous, without rugae; lateral propodeal area alutaceous, with dense white setae; nucha very short, coriaceous, without longitudinal sulci dorsolaterally and laterally.

Forewing longer than body, with distinct brown veins, margin with long dense cilia; radial cell 3.6x longer than broad, R1 and Rs nearly reaching wing margin; areolet large, triangular, well-delimited by distinct veins; Rs+M well-pigmented, nearly reaching basalis halfway along its height. Tarsal claws simple, without basal lobe.

Metasoma slightly longer than head+mesosoma, as long as high in lateral view, smooth, glabrous; 2nd metasomal tergite basally with dense white setae only laterally, ring of dense setae interrupted dorsally; 2nd tergite extending to 1/3 length of metasoma; prominent part of ventral spine of hypopygium slightly longer than broad in ventral view, with long white setae, extending beyond apex of spine but never forming a tuft. Body length 2.9–3.5 mm (n=6).

Gall ( Figs 97–99 ). Galls on staminate catkins, 12–24 mm in diameter, round, reddish, slightly pubescent, the inner cell has no air space around it.

Biology. Only asexual generation females are known which induce galls on Chrysolepis chrysophylla and C. sempervirens . Galls start to develop in late May-early summer, mature in September-October and fall to the ground and overwinter in the leaf litter. Some galls remain on the trees and can be collected through winter, although these galls may remain on the trees due to attack by inquilines that could inhibit complete development of the galls (the authors collected some in January that contained only inquiline larvae).

Distribution. USA, California and Oregon.

Figures

FIGURES 86–91. Dryocosmus castanopsidis, asexual female: 86–89, head: 86, anterior view, 87, dorsal view, 88, posterior view, 89, lateral view. 90, antenna. 91, forewing, part.

FIGURES 92–96. Dryocosmus castanopsidis, asexual female: 92–93, mesosoma: 92, lateral view, 93, dorsal view. 94, mesosoma and propleura, anterior view. 95, metascutellum and propodeum, posterodorsal view. 96, metasoma, lateral view.

FIGURES 97–99. Dryocosmus castanopsidis, asexual galls on catkins: 97–98, general view, note also that 98 contains asexual galls of D. juliae, 99, dissected gall with larva inside.