Druon laceyi (agamic)

Andricus lustrans (agamic)

Striatoandricus aciculatus (agamic)

Druon gregori (agamic)

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

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 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.

Andricus lustrans Beutenmüller 1913, comb. rev.

Zopheroteras vaccinii Burks, 1979.
Callirhytis lustrans Weld, 1926.
Andricus dimorphus verifactor, Kinsey, 1922.
Andricus impositus, Beutenmüller, 1918.
Acraspis vaccinii (erroneously associated with gall only) Ashmead, 1887.

The gall of A. lustrans was first described by itself (without the larva or adult wasp) from Quercus stellata Wangenh. (Osten Sacken, 1862). As this name based on gall alone was established before 1931, it is considered valid according to ICZN article 23.3.2. Ashmead described a new wingless wasp and erroneously associated it with the gall Osten Sacken had described as Acraspis vaccinii Ashmead, 1887 (later transferred to Zopheroteras vaccinii by Beutenmüller in 1909a), while reprinting Osten Sacken’s description of the gall (Ashmead 1887).

In 1913 Beutenmüller described the wasp (Fig. 19–21) without the gall as Andricus lustrans Beutenmüller, 1913, and the same species with its gall a few years later which he named Andricus impositus Beutenmüller, 1918. He commented that the gall of A. impositus is similar to Z. vaccinii but the wasp did not match (Beutenmüller, 1918). Kinsey also separately described this species under the name Andricus dimorphus var. verifactor Kinsey, 1922, reared from Texas, Oklahoma, and Louisiana. In 1926, Weld concluded that A. impositus and A. dimorphus var. verifactor are the junior synonyms of A. lustrans, and transferred the species to Callirhytis (Weld, 1926). Most recently, the species was then erroneously synonymized with Z. vaccinii by Burks (1979) based on Ashmead’s error. The senior author examined the holotype specimen and freshly collected materials (Figs. 19–22), reinstating the name A. lustrans as the species lacks the diagnostic characteristics of Callirhytis. In the Nearctic Cynipini phylogeny by Ward et al. (2022), A. lustrans was recovered as the sister group to an undescribed “pentagonal cluster” gall, both of which are related to Andricus pisiformis Beutenmüller, 1911 and Andricus quercusstrobilanus (Osten Sacken, 1862). A similar-looking gall was recently described as Andricus chapmanii Melika & Abrahamson, 2021, but the adults of A. lustrans can be easily separated using characters such as the incomplete notaulus (Fig. 21), and metasomal tergites smooth (Fig. 19) (Melika et al. 2021a).

There is a large series of over 100 specimens collected from Bronx Park in NY that are identified as A. lustrans (identified as A. impositus) collected by Beutenmüller (1918) at NMNH, which he stated as common in the region but is becoming urbanized. There are no current records of this species on iNaturalist outside of TX, which could suggest a reduction in their distribution, despite Q. stellata being found across eastern US. Additional host records include Quercus sinuata var. breviloba (Torr.) C.H.Mull. (Weld 1959).

Striatoandricus aciculatus (Beutenmüller, 1909), comb. nov.

Andricus aciculatus Beutenmüller, 1909

Striatoandricus aciculatus was first described based on specimens reared in College Station, TX from post oak (Quercus minor (Marshall) Sarg. = Q. stellata) (Beutenmüller 1909b), and have also been reported from Quercus durandii Buckley (= Quercus sinuata Walter) and Quercus lyrata Walter (Weld 1959). This species fits the morpho- logical characteristics of Striatoandricus such as the striated metasoma (Figs. 23–25), and is therefore transferred herein. Similar galls have been observed on iNaturalist across multiple US states surrounding the Gulf of Mexico (e.g. on Quercus austrina Small, iNaturalist observation 94165953), but specimens are needed to confirm the true range of S. aciculatus.

Druon gregori Melika, Nicholls & Stone 2022

Druon gregori is a new species described earlier this year in Cuesta-Porta et al. (2022), known only from the Santa Catalina and Chiricahua Mountains in Arizona on oaks in the Series Leucomexicanae. Our record (Figs. 27– 30) represents both a new state record (TX), and new plant record (Quercus mohriana Buckley × Quercus havardii Rydberg hybrid, iNaturalist observation 109484892, 103440540, 103440538) for the species. Additionally, a similar gall has been observed in New Mexico on Quercus turbellina Greene (iNaturalist observation 107224635), which would suggest that D. gregori can be found across these southwestern US states on Leucomexicanae oaks.

Discovery through iNaturalist: new species and new records of oak gall wasps (Hymenoptera: Cynipidae: Cynipini) from Texas, USA