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Corresponding author: Andrew A. Forbes ( andrew-forbes@uiowa.edu ) Academic editor: Andreas Köhler
© 2020 Hannah C. Ericson, Andrew A. Forbes.
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Citation:
Ericson HC, Forbes AA (2020) Description of the new species Coptera tonic (Hymenoptera, Diapriidae), a pupal parasitoid of Rhagoletis juniperina Marcovitch (Diptera, Tephritidae), and revised partial keys to Nearctic Coptera Say. ZooKeys 985: 49-60. https://doi.org/10.3897/zookeys.985.56974
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A new species of the parasitic wasp Coptera Say was previously distinguished from other species via correspondence between ecological (host) differences and DNA barcodes. A description and figures for Coptera tonic sp. nov., along with revisions to existing keys that allow it to be distinguished from other Nearctic species without the aid of molecular characters, is provided in this work.
Coptera cingulatae, Coptera pomonellae, Eastern red cedar, Psilini
Coptera Say, 1836 is a genus of parasitic wasps in family Diapriidae with a near-worldwide distribution.
Coptera species delimitation and ascertainment of host breadths have both proved challenging. These issues can be especially problematic when identifying potential biocontrol species if apparent oligiphagous species are actually complexes of cryptic specialists (e.g., Coptera silvestrii (Kieffer, 1913);
Collections of Coptera from known hosts in soil, coupled with DNA barcoding (sequencing of short segments of the mitochondrial COI gene), have proved useful in distinguishing among species, determining host associations, and identifying possible new species. Collections and barcoding of Coptera differentiated a new species associated with the juniper maggot fly, Rhagoletis juniperina Marcovitch, 1915 from the apparently cryptic species Coptera pomonellae Muesebeck, 1980 that attacks Rhagoletis pomonella (Walsh, 1867) and Rhagoletis suavis (Loew, 1862) flies in hawthorns and walnuts, respectively (
Though the combination of ecological and genetic data is useful for identification of reproductively isolated groups for taxonomically-challenging groups like Coptera (and see:
Collections used for study are described in
We developed a character matrix of all previously described Nearctic Coptera based on
We used a Hitachi S-3400N (Hitachi High-Tech Corp., Tokyo, Japan) to perform scanning electron microscopy (SEM) of males and females of C. pomonellae and the new species. Color photographs of the same two species were photographed using a Canon EOS 60D camera with a Canon MP-E 65 mm macro lens and a Canon Macro Ring Lite MR-14EX (Canon USA, Melville, NY), mounted on a StackShot Automated Focus Stacking Macro Rail (Cognysis Inc., Traverse City, MI). Stacked images were processed using Zerene Stacker (Zerene Systems LLC., Richland, WA) and Adobe Photoshop (Adobe, San Jose, CA, USA). Measurements of relevant body parts (in mm) were made using a Leica M125 stereomicroscope (Leica Inc., Switzerland) and Leica Application Suite v4.13. Holotypes, paratypes of the new species, and additional study specimens of Coptera pomonellae and Coptera cingulatae were deposited into the collection of the University of Iowa Museum of Natural History (
Coptera Say, 1836: 281.
Coptera polita Say. By monotypy.
Holotype
: USA • ♀; Ingham Co., East Lansing, MI; 42.7274, -84.4777; 3 Jul. 2011; Serdar Satar; reared from soil-collected pupa of Rhagoletis juniperina;
Paratypes : USA • ♀; Ingham Co., East Lansing, MI; 42.7274, -84.4777, 21 Aug. 2011; Serdar Satar; reared from pupa of R. juniperina, SUI:INS:04568 • 6♂; ibid; 8–9 Aug. 2011; SUI:INS:04569-04573, 04576 • ♂; ibid; 13 Aug. 2011, yellow pan trap; SUI:INS:04577 • ♀; Johnson Co., Iowa City, IA, 41.6509, -91.5603, 11 Sep. 2011, Andrew Forbes; yellow pan trap; SUI:INS:04574 • ♂; ibid; 10 Sep. 2011; SUI:INS:04565.
Coptera tonic females (Figs
Female. Length 3.0 – 3.1 mm; wing length 2.1 – 2.2 mm. Holotype length 3.0 mm; Holotype wing length 2.1 mm.
Color. Body (Fig.
Head.
Head about as long as broad; dorsum of head normally with several large punctures (Fig.
Mesosoma.
Pronotum smooth. Notaulices on mesoscutum fine and slightly broadened posteriorly; scutellum weakly convex; paired punctures at apex of scutellum moderately large and separated by less than the shortest diameter of either puncture (Fig.
Metasoma. Petiole of abdomen about 1.5 times as long as wide; petiole with all three dorsal longitudinal carinae strong but median one reduced on some specimens (Fig.
Male. Length 2.5–3.0 mm; wing length 2.1–2.3 mm.
Color. Body black; legs (including coxae) honey yellow; antennal scape black; flagellum testaceous; eyes and 3 ocelli tan; wings slightly infuscated.
Head. Head wider than long; dorsum of head normally with several large punctures; distances from lateral ocelli to posterior margin of occiput slightly longer than eyes, temples roundly receding, in lateral view slightly narrower than eyes; malar space nearly half as long as eyes; antennae slender with uniform thickness throughout, 14-segmented; all flagellomeres at least twice as long as wide with apical segment about three times as long as wide (Fig.
Mesosoma.
Pronotum smooth. Notaulices on mesoscutum fine, slightly broadened posteriorly; scutellum flat; paired punctures at apex of scutellum each subdivided into two smaller punctures (Fig.
Metasoma. Petiole about 1.5 times as long as wide; petiole with all three dorsal longitudinal carinae strong and complete; median sulcus of large tergite not reaching the middle of the segment; basal lateral sulci not defined.
The species name is a noun in apposition and refers to tonic water; this parasitic wasp and tonic water are both at their best when in close association with products of Juniperus cones.
Coptera tonic is a parasitoid of the juniper maggot fly, Rhagoletis juniperina, a parasite of the female cones of Eastern red cedar (Juniperus virginiana) and other members of genus Juniperus. Though oviposition has not been directly observed in C. tonic, these wasps have only been reared from pupae floated from soils, and not from larvae extracted from juniper cones, suggesting that attack likely occurs during the fly’s pupal stage after it has left the cone. Some pan trap collections of C. tonic (e.g., the female paratype labeled “Crab Apple”) were made under or near male Juniperus, suggesting that these wasps may use plant volatiles as an indicator for host searching. All known adults were captured or emerged from pupae between late July and early October (
Existing collections of C. tonic are limited to Iowa and Michigan. However, Rhagoletis juniperina is distributed across the continental United States and into southern Canada (
15 | Antennae thickening very gradually to apices, none of flagellomeres broader than long; paired punctures at apex of scutellum usually very small and separated by more than diameter of one of them | polita Say |
– | Antennae more strongly clavate; preapical segments clearly wider than long (Figs |
26 (new couplet) |
26 | Metapleuron rather thinly hairy; paired punctures at apex of scutellum separated by more than ½ of breadth of either puncture (Fig. |
pomonellae Muesebeck |
– | Metapleuron densely hairy; paired punctures at apex of scutellum separated by less than ½ of breadth of either puncture (Fig. |
tonic , new species |
We also propose the following revisions to
26 | Hindcoxae darkened basally; antennae and labrum black or blackish; polished disk of scutellum very small, not nearly twice as wide as unusually large lateral fovea | tenucornis Muesebeck |
– | All coxae yellow to orange; antennae and labrum yellow or brown, not black; polished dish of scutellum at least as broad as lateral fovea (Figs |
28 (new couplet) |
28 | Antennae usually largely yellow or yellowish brown, never entirely black, labrum brownish yellow. Paired punctures at apex of scutellum medium sized, widely separated | cingulatae Muesebeck |
– | Flagellomeres of antennae testaceous (Fig. |
tonic , new species |
Serdar Satar (Çukurova University) and Jim Smith (Michigan State University) collected most of the C. tonic material. SEM imaging support was provided by Phil Pagano and Kenny Horkley at the Iowa Center for Research, Exploration, and Advanced Technology in Engineering and Sciences (Iowa CREATES). Comments and questions from Ali Asghar Talebi and an anonymous reviewer substantially improved the manuscript from its original form.