Research Article |
Corresponding author: Brendan O’Loughlin ( bso2@rice.edu ) Academic editor: Jonah M. Ulmer
© 2024 Brendan O’Loughlin, Pedro F. P. Brandão-Dias, Michael W. Gates, Scott P. Egan.
This is an open access article distributed under the terms of the CC0 Public Domain Dedication.
Citation:
O'Loughlin B, Brandão-Dias PFP, Gates MW, Egan SP (2024) Description of a new species of Chrysonotomyia Ashmead from Houston, Texas, USA (Hymenoptera, Chalcidoidea, Eulophidae). ZooKeys 1212: 241-254. https://doi.org/10.3897/zookeys.1212.127537
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A new species of the genus Chrysonotomyia Ashmead, Chrysonotomyia susbelli sp. nov., is described from the Rice University campus in Houston, Texas, USA. The species is a parasitoid emerging from Neuroterus nr. bussae galls in leaves of the southern live oak (Quercus virginiana). This represents the 6th species described from North America north of Mexico and the first in the world known to parasitize cynipid gall wasps. This discovery hints at an entire undiscovered niche between Chrysonotomyia parasitoids, cynipid gall wasps, and oaks in the Nearctic, which is a global biodiversity hotspot for oaks and cynipids. This new species description is complemented by mtDNA-COI-barcode data and information on the natural history of this species. We record host association, phenology, and report a leaf-scanning behavior performed by females, presumably to search for host galls. Modifications to the key of New World members of the genus (
Cynipidae, live oak, Neuroterus nr. Bussae, parasitoid, Quercus virginiana
Chrysonotomyia Girault, 1904 is a genus of parasitic wasps in the family Eulophidae (Hymenoptera) with close to 173 described species (
Number of Chrysonotomyia species known to attack galls or endoparasitoids from each taxonomic family.
Order | Family | Number of associated Chrysonotomyia sp. |
---|---|---|
Diptera | Cecidomyiidae | 27 |
Hemiptera | Coccidae | 1 |
Diaspidae | 1 | |
Psyllidae | 2 | |
Hymenoptera | Cynipidae | 1 |
Torymidae | 1 | |
Lepidoptera | Momphidae | 1 |
Galls of Unknown Taxonomic Affinity | 10 |
While the genus has a near-cosmopolitan distribution, its center of diversity is in the Americas, specifically in the Neotropics (
Here, we describe the sixth species of Chrysonotomyia known from the United States, the first of the entire genus confirmed to attack cynipid gall wasps, and the first in a confirmed association with oaks in the genus Quercus. Specifically, we discovered Chrysonotomyia parasitoids emerging from leaf galls induced by Neuroterus nr. bussae Melika & Nicholls, 2021 (Hymenoptera, Cynipidae) on the southern live oak Quercus virginiana Mill. (Fagaceae). The morphological species description is complemented by genetic barcode sequences and details of their natural history and phenology. We also include suggested modifications to the key by
Individuals were reared from galls at the type locality, Houston, Texas, on the Rice University campus (29.717, −95.402) and collected as adults on the host plant, Quercus virginiana. Currently, this is the only location from which the species has been confirmed. However, we believe it should be found within the range of its insect host on its host plant, found throughout the southern United States along the Gulf Coast (Cavender-Bares et al. 2015;
The description of the species was made under a Leica 205C stereomicroscope. Specimens were imaged using a Macropod using Canon EOS R6 equipped with a Canon 113 Zoom Lens EF 70–200mm and M Plan Apo 10× and 20× compound objective lenses. Images were then stacked in Zerene Stacker (v. 1.04 Build T2023–114 06–11–1120, Zerene Systems). Final images were processed in Adobe Photoshop 2023.
The holotype, syntype, and all paratypes were deposited in the
National Museum of Natural History in Washington D.C (
Three individuals were selected for molecular barcoding: one male and one female that had emerged from galls (harvested 4/18/2022, emerged 5/6/2022 and 5/4/2022 respectively), and one female caught via aspirator directly from the host plant leaf (May 2023). Genetic material was extracted using DNeasy Blood and Tissue kits (Qiagen Inc., Valencia, CA). We used a pair of degenerate primers to amplify a segment of the mitochondrial cytochrome oxidase (mtDNA - COI) gene using standard PCR protocols (
Abbreviations follow the terminology used in
HE/MS/WM Ratio of height of eye (HE), malar space (MS) and width of mouth opening (WM)
POL/OOL/POO Ratio of distance between posterior ocelli (POL), distance between the posterior ocellus and the compound eye (OOL) and the distance between occipital margin and posterior ocelli (POO)
WH/WT Ratio of width of head in dorsal view (WH), and the width of thorax (WT), measured across widest part
LW/>LM/HW Ratio of length of wing (LW), length of marginal vein (LM) and height of wing (HW)
PM/ST Ratio of length of postmarginal vein (PM) and the length of stigmal vein (ST)
MM/LG Ratio of length of mesosoma measured from anterior margin of pronotum to posterior margin of propodeum (MM) and the length of gaster (LG)
Chrysonotomyia Ashmead, 1904. Journal of the Linnean Society (Zoology) 25: 166.
Eulophus auripunctatus Ashmead.
Subtorular sulci present; clypeus delimited laterally only (sometimes weakly so); occiput without vertical groove or weak fold between occipital margin and occipital foramen; postmarginal vein usually shorter (0.1–0.8×) than stigmal vein (but 2.3–3.2× as long in species group neeigena); midlobe of mesoscutum with one pair of setae (2–3 pairs in a few species); notauli poorly delimited or missing in posterior part; petiolar foramen rounded triangular; petiole very short, as a narrow band (as long as wide in a very few species); male phallobase: digitus with one spine (a few species with two spines (mainly the species in group planiseta), digitus is missing in species group laeviscuta) (
Diagnosis. Midlobe of mesoscutum with one pair of setae; flagellomeres with short and asymmetric sensilla; digitus in male genitalia with one spine (
Mesosoma predominantly golden yellow with dark brown markings dorsally. Similar to C. corynata (Hansson, 2004) but differing in hue and dorsal patterning; dorsellum visible in dorsal view; antennae not distinctly clavate; flagellomere five dark brown; gaster with dark brown transverse bands, never more than two complete dorsally.
Length of body ♀ 1.0–1.2 mm, ♂ 0.9 mm.
Mesosoma female: Mesoscutum golden yellow with the posterior midlobe occupied by a transverse, metallic brown band flanked by small transverse dark bands on the sidelobes, the metallic brown band may appear metallic green when viewed at certain angles. Axillae golden yellow with 2–3 areas of dark brown coloration. Scutellum golden yellow with median longitudinal dark band, anterior and posterior edges lined with dark transverse bands. Dorsellum golden yellow. Propodeum light yellow with a dark brown transverse band (Fig.
Female gaster pale yellow with three incomplete dark transverse bands and apical ovipositor sheaths dark brown (Fig.
Head light yellow apically, transitioning to pale white below. Eyes pink. Scape pale white, pedicel light yellow with apical two-thirds of inner surface dark brown, flagellomeres 1–4 yellow, flagellomere 5 brown (Figs
Both male and female antennae with pale white verticillate setae (Figs
Mesoscutum and scutellum with weak and small meshed reticulation. Dorsellum small, convex, and smooth (Fig.
Female gaster ovate. Ratio of MM/LG ♀ 1.0/1.1, ♂ 1.0/1.0
Known to parasitize Neuroterus nr. bussae (Fig.
Holotype
• United States: Houston, Harris County; 29.7179°N, 95.4048°W; 4.v.2022. ex. gall on Quercus virginiana; coll. Pedro Brandão-Dias (1♀; USNMENT01928159). Syntype • same data as holotype; 10.v.2022 (1♂; USNMENT01928158). Paratypes • (1♀;
The three mtDNA-COI sequences were, on average, 99.4% identical to each other and, on average, 91.1% identical to Chrysonotomyia sp. PLACZ361-20 from Guanacaste, Costa Rica in the BOLD database. The sequences can be accessed through GenBank accession numbers PP468569, PP468570, and PP468571. See Suppl. material
Adult C. susbelli sp. nov. were observed emerging from galls in the lab from 18 April to 10 May 2022, and we made additional observations of adult C. susbelli sp. nov. on the leaves of the southern live oak (Q. virginiana) from 20 April to 18 May 2023.
From Latin sus belli, roughly translating to “warpig”, in reference to the mascot of the Rice University dormitory Wiess College where the first author currently resides, whose official color is similar to the golden yellow of the dorsal mesosoma. Wiess College is named for Harry Carothers Wiess (1887–1948), one of the founders and one-time president of Humble Oil, whose generosity, with time, mind, and resources, greatly shaped the expansion of Rice University.
Chrysonotomyia susbelli sp. nov. most closely keys to C. corynata using the key by
Chrysonotomyia corynata is also geographically distant and only known from specimens collected in the Mexican states of Coahuila, Guanajuato, Michoacán, Oaxaca, Puebla and Zacatecas (
To incorporate C. susbelli sp. nov. into the key in
47(46) | Mesosoma completely yellowish-white; forewing with denser setation (as in fig. 284) | C. crinipennis (♀) |
– | Mesosoma with some parts brown; forewing with less dense setation (fig. 285) | 47a |
47a(47) | Flagellomeres similar in color to scape | C. corynata |
– | Flagellomeres significantly darker than scape | C. susbelli sp. nov. |
While all New World Chrysonotomyia with a reported host association parasitize galls (
Of the 103 Chrysonotoymia previously described from North America, only 33 species (~32%) have known hosts (
Number of Chrysonotomyia species known to attack galls or endoparasites associated with each taxonomic plant family.
Plant Family | Number of associated Chrysonotomyia sp. |
---|---|
Aquifoliaceae | 1 |
Cannabaceae | 1 |
Cecropiaceae | 5 |
Celastraceae | 1 |
Chrysobalanaceae | 2 |
Ericaceae | 1 |
Fabaceae | 6 |
Fagaceae | 1 |
Lauraceae | 1 |
Lecythidaceae | 2 |
Loranthaceae | 1 |
Malvaceae | 1 |
Melastomataceae | 2 |
Moraceae | 4 |
Myrtaceae | 2 |
Olacaceae | 1 |
Piperaceae | 2 |
Polygonaceae | 2 |
Rhizophoraceae | 1 |
Rosaceae | 1 |
Rubiaceae | 2 |
Sapindaceae | 1 |
Smilaceae | 1 |
Urticaceae | 2 |
Verbenaceae | 1 |
Vitaceae | 1 |
Five other Chrysonotomyia are known from the United States: C. aemilia Girault, 1917; C. auripunctata Ashmead, 1894; C. maculata Delucchi, 1962; C. phenacapsia Yoshimoto, 1972; and C. pherocera Hansson, 2004 (
Chrysonotomyia aemilia. This species is known only from Florida (
Chrysonotomyia auripunctata. This species is known from Florida, Brazil, Costa Rica, Guatemala, Guyana, Mexico, Panama, St. Vincent, and Trinidad. It can be distinguished from susbelli sp. nov. by the scutellum hiding the dorsellum in dorsal view and the presence of two hair lines radiating from the stigmal vein (
Chrysonotomyia maculata. This species is known from Canada, Costa Rica, Honduras, and the USA (Florida, Maryland, New York, Ohio, Tennessee, and Texas). It can be distinguished from C. susbelli sp. nov. by its pale antennae, distinctly elongate female gaster, and partly to completely hairy radial cell (
Chrysonotomyia phenacapsia. It can be distinguished from susbelli sp. nov. by the midlobe of the mesoscutum with two pairs of setae, and strong reticulation on the frons above the frontal suture (
Chrysonotomyia pherocera. Known from Costa Rica, Mexico, and the USA (Florida and Missouri). It is easily distinguishable from C. susbelli sp. nov. by the anterolateral edges of the vertex produced forward of the eyes, creating “horns” (
While C. susbelli sp. nov. has officially been recorded only from Houston, citizen-science observations on platforms such as Bugguide.net and iNaturalist hint at a possibly much broader distribution, and/or the presence of closely related undescribed species across the United States. There is one iNaturalist observation from Manitoba, Canada (https://www.inaturalist.org/observations/183137943) that appears to show a superficially similar Chrysonotomyia in association with the cynipid Druon ignotum Bassett, 1881. Two other observations, one from Bugguide in Texas (https://bugguide.net/node/view/908461) and the other from iNaturalist in New York (https://www.inaturalist.org/observations/173105503), show a similar Chrysonotomyia associated with galls on Vitis spp. (Vitaceae). Whether these observations represent C. susbelli sp. nov. or a closely related species are difficult to tell without specimens and genetic data.
Our work suggests that there might be more undescribed Chrysonotomyia hiding among the 90+ oak species in the US and Canada and 180+ oak species in Mexico (
Interestingly, we also describe here a novel leaf-scanning behavior performed by females on the leaves of live oaks (Suppl material
We would like to thank Robert Kresslein for assistance with photography and Dr Jim Woolley (emeritus, Texas A&M University) for providing images of C. corynata used herein.
The authors have declared that no competing interests exist.
No ethical statement was reported.
Funding is provided through the Fondren Library Open Access Author Fund.
Brendan O'Loughlin: Conceptualization, Methodology, Validation, Formal Analysis, Investigation, Resources, Writing – Original Draft, Visualization; Pedro Brandão-Dias: Methodology, Data Curation, Writing – Review and Editing; Michael Gates: Investigation, Supervision; Scott Egan: Supervision, Project Administration.
Brendan O'Loughlin https://orcid.org/0009-0002-9925-8492
Pedro F. P. Brandão-Dias https://orcid.org/0000-0001-8583-0617
Michael W. Gates https://orcid.org/0000-0002-5760-1371
All of the data that support the findings of this study are available in the main text or Supplementary Information.
Leaf scanning behavior of Chrysonotomyia susbelli sp. nov.
Data type: mp4
Raw COI sequences of Chrysonotomyia susbelli sp. nov.
Data type: fasta