Druon laceyi Zhang, Sasan & O’Kennon, 2022

Zhang, Y. Miles, Sasan, Kimberlie, O’Kennon, Robert J. & Kranz, Adam J., 2022, Discovery through iNaturalist: new species and new records of oak gall wasps (Hymenoptera: Cynipidae: Cynipini) from Texas, USA, Zootaxa 5168 (1), pp. 63-74 : 65-69

Druon laceyi Zhang, Sasan & O’Kennon sp. n.

Figs. 1–18

urn:lsid:zoobank.org:act:26073933-835C-4BFC-8B93-B0FC4D50A05A

Materials examined: Holotype ♀, USA, TX, Fort Worth , Botanical Research Institute, 24.IX.2020, 32.7419, - 97.3638., K.Sasan & R. O’Kennon Leg., reared from midrib leaf galls on Quercus laceyi . Paratypes 8♀, same locality as holotype, USNM . 3♀, same locality as holotype, UB .

Diagnosis. Druon laceyi belongs to the Druon group in which the front of the head is rusty brown and the posterior part of the head and mesosoma are dark brown to black ( Cuesta-Porta et al. 2022). It keys to couplet 8 of the key in Cuesta-Porta (2022), and is morphologically similar to Druon fullawayi ( Beutenmüller, 1913) and Druon gregori Melika, Nicholls & Stone, 2022 . Druon laceyi can be distinguished from D. fullawayi by the incomplete notauli, and the presence of a broad rugose elevated central carina dividing the mesoscutellar foveae. Whereas D. fullawayi has the notauli complete and well-delimited, and the mesoscutellar foveae divided by a thin, strong carina. Druon laceyi can also be distinguished from D. gregori by the incomplete notauli, scutellar foveae divided by an alutaceous elevated triangle, smooth speculum, and T2 of the metasoma very short (not reach ⅓ of the length), all tergites smooth, and the bi-colored head. Whereas D. gregori has complete notauli, speculum sculpted as the rest of the mesopleuron, T2 occupies at least half of the length, T3 and following punctured, and an uniformly black head. Additionally, D. laceyi is only known from the oak Series ‘ Texas White Oak’ (sensu Hipp et al. 2020) in central Texas, whereas D. fullawayi is known only from Series Dumosae in California and Zacatecas in Mexico, while D. gregori only from Series Leucomexicanae found on the Santa Catalina and Chiricahua Mountains in Arizona.

Description. ASEXUAL FEMALE (holotype). Body length 2.2mm. Head dark brown, except lower face and gena light brown; antenna scape to F3 light brown, F3–F11 dark brown; mesosoma and metasoma dark brown except edges of metasomal tergites light brown, legs light brown except tarsal claws dark brown. Wing veins are dark brown ( Fig. 4, 5 ).

Head alutaceous, trapezoid, with sparse setae, denser on lower face ( Fig. 6, 7 ), 1.8× as broad as long in dorsal view and subequal to mesosoma. Gena alutaceous, not broadened behind eye; malar space with striae radiating from clypeus and reaching eye, 0.3× as long as height of eye. Ratio of POL:OOL:LOL is 2.1:1:1; all ocelli ovate, of the same size ( Fig. 9 ). Transfacial distance equal to height of eye, toruli located in mid height of head; diameter of antennal torulus 1.6× as large as the distance between them; distance between torulus and inner margin of eye subequal the diameter of torulus; inner margins of eyes slightly converge ventrally. Lower face strigose, with dense white setae, the median elevated area coriaceous; clypeus rounded, anterior tentorial pits distinct, epistomal sulcus and clypeo-pleurostomal line indistinct ( Fig. 8 ). Frons alutaceous, with few white setae; interocellar area microreticulate. Vertex and occiput delicately coriaceous to alutaceous. Antenna with 11 flagellomeres; placodeal sensilla on F3–F11, absent on F1–F2 ( Fig. 10 ). Ratio of scape:pedicel:flagellomeres 1–11 is: 1.6:1:2.4:2.3:2.3:1.8:1.6:1.6:1.3:1.3:2.6. Placodeal sensilla on F3–F11; three coeloconica present on the apical flagellomeres in the form of small rounded black pits, with one on the distal margin of F11, and one on the distal margin and a second ⅔ way down the F12 ( Fig. 11 ).

Mesosoma convex, 1.2× as long as high ( Fig. 13 ). Pronotum with transverse striate laterally, with dense white setae; Mesoscutum reticulate; Notauli incomplete on the anterior 1/3, narrow, weakly impressed, slightly converging and broadened at the posterior end, with few white setae along notauli; anterior parallel and parapsidal lines very faint, posterior medial sulcus absent ( Fig. 14 ). Mesoscutellum coriaceous, setose, rounded in dorsal view; Mesoscutellar foveae distinct, transversely ovate, 1.9× as broad as high, smooth, shiny, separated by a broad rugose elevated central carina. Mesopleural triangle rugose. Mesopleuron striato-reticulate, with setae on the dorsal and ventral edges; speculum smooth; axillar area reticulate, glabrous; axillula setose, with parallel longitudinal striae; subaxillar bar area smooth. Metapleural area setose, metapleural sulcus reaching ½ way of the mesopleuron. Metanotal trough smooth, glabrous; propodeum central propodeal area smooth, with few irregular rugae, lateral propodeal carinae curved outwards in posterior 1/3; lateral propodeal area with dense long white setae ( Fig. 16 ). Nucha with numerous rugae. Tarsal claws with tooth ( Fig. 15 ). Fore wing longer than body, hyaline, with dense cilia on margin, radial cell open, 3.8× as long as broad; R1 not reaching wing margin, Rs nearly straight, nearly reaching wing margin; areolet large, triangular, closed and distinct. Rs+M distinct on 3/4 of distance to M and its projection reaching M at its half height ( Fig. 12 ).

Metasoma longer than head + mesosoma, higher than long in lateral view; T2 very short (not reach ⅓ of the metasomal length), all tergites smooth; T2 with setae on the anterior half, T7 and hypopygium setose ( Fig. 17 ). Ventral spine of hypopygium slender, prominent part at least 2.4× as long as broad, with sparse, long white setae, extending beyond the apex of spine ( Fig. 18 ).

Gall. Small clusters of 1-10 individual (unilocular) brown oval cells in the center of the leaf, emerging perpendicular from the midrib on both upper and lower leaf sides of Q. laceyi in the fall ( Figs. 1–2 ). Seen in abundance on nearly every leaf of each affected host. The cell surface when examined with a microscope shows numerous minute papillae covered with a crystalline material and sparse long white woolly hairs. The hairs weather away as the galls age, except near the base. Inside is a single thin-walled chamber ( Fig. 3 ). Cells stay firmly attached to the leaf when it falls. Leaf petioles frequently display a small darkened area, presumably where eggs were inserted. Approximately 2–3mm long and 1.5mm in diameter. Seen in Fort Worth, TX in October. Adults emerge the following February ( Fig. 4 ).

Biology. Only the asexual generation of this species is known, inducing aggregated detachable leaf galls on the top and bottom of the midrib of Q. laceyi . In addition to the gall inducer, inquilines ( Cynipidae : Synergus Hartig, 1840 ) and parasitoids ( Eupelmidae : Brasema Cameron, 1884 & Ormyridae : Ormyrus Westwood, 1832 ) have also been reared from galls of the same collection (iNaturalist observations: 66896457, 66896459, 68692701, 80260145, 80260150, 80260151, 80260156).

Distribution. Currently known only from Texas. It is possible that this species also occurs in Oklahoma and northern Mexico, where the host plant is known. Further research is necessary to establish the distribution of this species.

Etymology. Named after its host plant, Quercus laceyi .

Figures

FIGURES 1–5. Druon laceyi sp. nov.. 1. Quercus laceyi with mature galls. 2. Mature galls with an emergence hole. 3. Cross section of gall showing adult and empty chambers. 4. Live anterodorsal habitus. 5. Lateral habitus of holotype.

FIGURES 6–12. Druon laceyi sp. nov.. 6. Frontal view of head. 7. Anterolateral view of head. 8. Clypeus. 9. Dorsal view of head. 10. Antenna 11. Closeup of antenna with coeloconica sensillae. 12. Wings.

FIGURES 13–18. Druon laceyi sp. nov.. 13. Lateral view of mesosoma. 14. Dorsal view of mesosoma. 15. Tarsal claw. 16. Propodeum. 17. Lateral view of metasoma. 18. Ovipositor tip.