Druon quercusflocci ( Walsh, 1864 ) Cuesta-Porta & Melika & Nicholls & Stone & Pujade-Villar, 2022

Cuesta-Porta, Victor, Melika, George, Nicholls, James A., Stone, Graham N. & Pujade-Villar, Juli, 2022, Re-establishment of the Nearctic oak cynipid gall wasp genus Druon Kinsey, 1937 (Hymenoptera: Cynipidae: Cynipini), with description of five new species, Zootaxa 5132 (1), pp. 1-92 : 50-53

Druon quercusflocci ( Walsh, 1864) , comb. nov.

Figs. 139–150

? Cynips Quercus-lana Fitch, 1859: 814, adult, galls (see comments)

Cynips quercus flocci Walsh, 1864: 482 , female, gall.

Cynips ( Andricus ?) flocci Osten Sacken, 1865: 352 .

Andricus flocci (Walsh) : Mayr, 1881: 28.

Andricus quercusflocci (Walsh) : Burks, 1979: 1087.

Types examined. Walsh types are supposed to be deposited in the Entomology Type Collection at the Academy of Natural Sciences of Philadelphia. However, neither type specimens nor non-type specimens were found in the collection. We presume that these specimens are lost.

Additional material examined. Five females on one cardboard “158x from Bassett flocci; Collection C.V.I. Riley” from general collection in USNM: http://n 2t.net/ark:/65665/354a22430-9d15-4580-88ac-9336113a889c; examined by GM. 15 galls and 5 females ( PHDNRL) “ USA, NC, Pamlico Co., Camp See Gull , nr. Arapahoe, Q. alba , leg. G. Melika, 1995.x.15 ” .

Diagnosis. This species belongs to the Druon group with the head rusty brown frontally, mesosoma light brown and metasoma smooth or with indistinct sparse micropunctures, as also occurs in D. quercuslanigerum , D. protagion , D. pattoni , D. rusticum and D. receptum . Druon quercusflocci differs from all these species in the transverse shape of its head in frontal view, gena distinctly broadened behind eye in frontal view ( Fig. 139 ), and long mesoscutellum ( Fig. 147 ) (in the other species the head is rounded or trapezoid, gena only slightly broadened behind eye ( Figs. 113 , 125 , 151 , 190 ), mesoscutellum as long as wide or slightly elongated).

Redescription. Asexual female( Figs.139–149 ).Body uniformly dark brown;antenna,mandibles,palpi,legs paler.

Head alutaceous, with uniform sparse setae; transverse, 1.3× as broad as high and slightly broader than mesosoma in frontal view; 2.0× as broad as long in dorsal view. Gena alutaceous, broadened behind eye in frontal view, slightly narrower than transverse diameter of eye in lateral view. Malar space alutaceous, with numerous striae radiating from clypeus and not reaching eye, malar sulcus absent. Eye 2.8× as high as length of malar space. Inner margins of eyes parallel. POL 1.8× as long as OOL, OOL 1.4× as long as diameter of lateral ocellus and 1.4x as long as LOL, all ocelli slightly ovate, of same size. Transfacial distance 1.2× as long as height of eye; toruli located slightly above mid height of eyes and frons shorter than height of lower face, diameter of antennal torulus 1.35× as long as distance between them, distance between torulus and eye slightly longer than diameter of torulus; lower face alutaceous, with a few white setae, with short delicate striae above malar space; slightly elevated median area delicately coriaceous, with few setae. Clypeus rectangular, broader than high, smooth, glabrous, impressed, without setae; ventrally rounded, not emarginate and without median incision; anterior tentorial pit large, elongated, distinct, epistomal sulcus distinct, clypeo-pleurostomal line well impressed. Frons uniformly alutaceous, without striae or setae, impressed area below central ocellus smooth, glabrous; interocellar area alutaceous. Vertex, occiput alutaceous, with long dense setae; postocciput with transversely orientated surface elements; postgena smooth, glabrous; posterior tentorial pit large, elongated, area below impressed; occipital foramen slightly higher than height of postgenal bridge; hypostomal carina emarginate, continuing into postgenal sulci which diverge distinctly towards occipital foramen, postgenal bridge anteriorly slightly broader than occipital foramen. Antenna longer than head+mesosoma, with 11 flagellomeres, pedicel slightly longer than broad; flagellomeres sequentially broadening towards apical end of antenna; scape+pedicel slightly longer than F1, F1 2.2× as long as pedicel and slightly longer than F2; F2 slightly longer than F3; F3 slightly longer than F4, F5=F6 and shorter than F4, F7–F11 nearly equal in length and shorter than F5; placodeal sensilla distinct on F4–F12.

Mesosoma 1.2× as long as high, with very few white setae. Pronotum smooth, glabrous dorsally, with numerous delicate parallel striae extending onto entire pronotum laterally (ventrolateral rugae stronger), with piliferous points around setae; anterior rim of pronotum impressed, foveolate; propleuron smooth, glabrous, with few setae. Mesoscutum uniformly and entirely weak reticulate, without setae, slightly longer than broad (greatest width measured across mesoscutum level with base of tegulae). Notauli complete, strongly converging posteriorly, gradually broadening towards posterior end; at posterior end the distance between notauli less than distance between notaulus and side of mesoscutum, notaulus furrow smooth, glabrous; anterior parallel line in the form of an impressed stripe with more delicate sculpture than rest of mesoscutum, extending to half of mesoscutum length; parapsidal line marked with broad smooth, glabrous area; median mesoscutal line absent; parascutal carina broad, smooth, reaching notaulus. Mesoscutellum distinctly elongated, longer than broad; disk of mesoscutellum uniformly dull rugose, with stronger rugae laterally and posteriorly, overhanging metanotum, with white setae posteriorly; circumscutellar carina present. Mesoscutellar foveae transverse, 2.0× as broad as high, smooth, glabrous, divided by a narrow, triangular, rugose elevated median carina. Mesopleuron entirely covered with delicate interrupted parallel striae, extending across mesopleuron, with long white setae posteroventrally; mesopleural triangle coriaceous, glabrous; dorsal and lateral axillar areas smooth, glabrous, with setae; axillula with delicate parallel longitudinal striae; subaxillular bar smooth, glabrous, triangular, posteriorly as high as height of metanotal trough; metapleural sulcus reaching mesopleuron at half of its height, upper part of sulcus indistinct, sulcus in lower part separating smooth, glabrous area, with some setae. Metascutellum smooth, glabrous, with some parallel longitudinal delicate carinae, as high as height of smooth, shining ventral impressed area; metanotal trough smooth, glabrous; central propodeal area smooth, glabrous, without rugae; lateral propodeal carinae strong, bent outwards in posterior 1/3 of propodeum height; lateral propodeal area smooth, glabrous, with few white setae and piliferous points. Nucha with few strong longitudinal parallel sulci dorsally and laterally. Tarsal claws with basal lobe.

Fore wing longer than body, hyaline, with short dense cilia on margin, veins brown, radial cell open, 4.2× as long as broad; Rs and R1 nearly reaching wing margin; areolet small, triangular, closed, indistinct. Rs+M distinct on 3/4 of its length, its projection reaching basalis slightly below mid height.

Metasoma slightly longer than head+mesosoma, higher than long in lateral view; second metasomal tergum with sparse setae anterolaterally, smooth, without micropunctures; all subsequent terga, including hypopygium, with delicate dense micropunctures (not reticulate). Prominent part of ventral spine of hypopygium 2.3× as long as broad in ventral view. Body length 1.9–2.2 mm (n = 5).

Gall. ( Fig. 150 ). Woolly, dirty white to pinkish pubescent galls, 10–12 mm long, 8.0– 8.5 mm broad and 4–5 mm high, containing 2–10 seed-like larval chambers attached at one end to the midrib on the upper or lower side of the leaf; the cluster of galls is usually elongated along the direction of the leaf midrib. The larval cells are distinct individually, rather than fused into a single mass, 0.2–1.0 mm in diameter, and covered with short crystalline hairs.

Biology. Only an asexual generation is only known, which induces leaf galls on Q. alba (Section Quercus , Series Albae ) in autumn.

Distribution. USA: Massachusetts to North Carolina, Michigan, Illinois, Missouri, Arkansas ( Burks 1979).

Comments. Fitch (1859) described a similar gall named Cynips Quercus-lana but the adults he reared are cynipid inquilines belonging to Synergus according to keys in Cresson (1887) and Lobato-Vila & Pujade-Villar (2021). Holotype deposited in USNM: http://n 2t.net/ark:/65665/35b33f67b-b93b-449b-bca7-12c897d8ef5b, examined by GM and confirmed as belonging to the genus Synergus . The galls are indistinguishable from other similar galls, and we cannot determine whether this gall corresponds to Andricus (now Druon ) quercusflocci . Dalla Torre & Kieffer (1910: 544) nevertheless considered Andricus quercusflocci to be a possible junior synonym of Andricus quercuslana . The specific name ‘ quercuslana ’ corresponds to a Synergus species, leaving the gall described by Fitch (1859) as unidentifiable (? Cynips quercuslana Fitch, 1859 ).

A sample of galls on leaves collected from Aguascalientes State ( Mexico) on Quercus potosina produced two adults morphologically resembling D. quercusflocci . The galls have a completely whitish woolly covering over clusters of 2–6 seed-like distinct larval chambers attached to the midrib of leaves ( Fig. 150 , right). The galls of D. quercusflocci from USA are densely pubescent, mainly orange-brown with some scattered white wool ( Fig. 150 , left). The internal structure of distinctly separated larval chambers is shared by both of these gall morphologies. The adults from Mexico differ slightly from typical D. quercusflocci by the following mesopleural and mesoscutellar characters. In the Mexican specimens, the oblique carinae of the mesopleuron are less impressed, the mesopleural triangle is inconspicuously pubescent with thin transparent scattered setae, and the mesoscutellum is round, while in D. quercusflocci the oblique mesopleural carinae are more impressed, the mesopleural triangle is clearly pubescent, and the mesoscutellum has parallel sides. We consider these differences insufficient to define two separate species, but the phenotypic differences in gall traits may indicate that the Mexican specimens belong to a different species. Alternatively, the differences may result from host plant effects on gall structure, as seen in some other oak cynipid galls with a wide host range (e.g. asexual generation leaf galls of Cynips quercusfolii Linnaeus, 1758 in the Western Palaearctic, which are smooth when developing on Quercus robur L. but covered with raised tubercles when developing on Q. petraea (Matt.) Liebl. ). Thus, we have not officially assigned the Mexican specimens to D. quercusflocci and await more material and further evidence, such as molecular data.

Figures

FIGURES 139–144. Druon quercusflocci, comb. nov., asexual female. 139–142, head: 139, frontal view, 140, dorsal view, 141, lateral view, 142, posterior view. 143, antenna. 144, mesosoma and propleura, frontal view.

FIGURES 145–148. Druon quercusflocci, comb. nov., asexual female. 145, mesosoma, lateral view. 146, mesoscutum, dorsal view. 147, mesoscutellum, dorsal view, 148, metascutellum and propodeum, posterodorsal view.

FIGURES 149–150. 149, Druon quercusflocci, comb. nov., asexual generation, metasoma, lateral view. 150, galls: D. quercusflocci (left), D. quercusflocci-like, Mexico (right).

FIGURES 113–118. Druon pattoni, comb. nov., asexual female. 113–116, head: 113, frontal view, 114, dorsal view, 115, lateral view, 116, posterior view. 117, antenna. 118, mesosoma and propleura, frontal view.

FIGURES 125–130. Druon protagion, comb. rev., asexual female. 125–128, head: 125, frontal view, 126, dorsal view, 127, lateral view, 128, posterior view. 129, antenna. 130, mesosoma and propleura, frontal view.

FIGURES 151–156. Druon quercuslanigerum var. quercuslanigerum, comb. nov., asexual female (Florida). 151–154, head: 151, frontal view, 152, dorsal view, 153, lateral view, 154, posterior view. 155, antenna. 156, mesosoma and propleura, frontal view.

FIGURES 190–193. Druon receptum, comb. rev., asexual female (lighter colour). 190–192, head: 190, frontal view, 191, dorsal view, 192, posterior view. 193, antenna.