Research Article |
Corresponding author: Chia-Hua Lue ( chiachia926@gmail.com ) Academic editor: Matthew Yoder
© 2016 Chia-Hua Lue, Amy C. Driskell, Jeff Leips, Matthew L. Buffington.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Lue C-H, Driskell AC, Leips J, Buffington ML (2016) Review of the genus Leptopilina (Hymenoptera, Cynipoidea, Figitidae, Eucoilinae) from the Eastern United States, including three newly described species. Journal of Hymenoptera Research 53: 135-76. https://doi.org/10.3897/jhr.53.10369
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The genus Leptopilina has historically been a poorly understood group. However, some species of Leptopilina are among the best-known model organisms for studying host-parasitoid interactions. As there is no identification system for Leptopilina in any part of the United States, we review species that were collected throughout their range in Eastern North America and those commonly used in laboratories. We provide a key for seven species, L. boulardi, L. heterotoma, L. clavipes, L. victoriae, L. decemflagella sp. n., L. maia sp. n. and L. leipsi sp. n., the last three of which are newly described here. This study is the first of its kind for Leptopilina species in North America, as our review and key were developed by examining a large number of specimens collected across broad chronological and geographic scales. This allowed us to account for the phenotypic variation within species, and helped us discover diagnostic characters. The geographic distribution and taxonomic information from this review provides a solid foundation for future research on Leptopilina.
Parasitoid wasps, Drosophila , Nearctic Region, geographic distribution, DNA barcoding
Parasitoid wasps (Hymenoptera: Apocrita) are a particularly speciose group of insects, potentially accounting for over 20% of all insect species (
The genus Leptopilina has historically been a poorly understood group, and it was not until the relatively recent revision by
Some species of Leptopilina are cosmopolitan and are present on all continents except Antarctica (
Specimens of Leptopilina for this study were obtained from two main resources. One was from freshly collected specimens by Lue and the other was from the extensive insect collections of the
Parasitoids were collected in the field using yellow pan traps, or by hand-held electric vacuum from traps that were baited with fermented peaches. Wasps were collected two times per day (early a.m. and late p.m.) when wasps were most active/present on the baits. Samples of the fruit baits were placed in 25mm × 95mm polystyrene vials and returned to the laboratory. Additional wasps were collected as they emerged from hosts that had been parasitized in the field. All insects were placed in 95% ethanol either immediately upon collection from the vacuum and laboratory reared samples or within 12 hours from when the yellow pan traps were first set out. Parasitoids were dry mounted on acid-free cards for examination. To morphologically circumscribe species, we included individuals from field collections as well as, all the North American Leptopilina specimens housed at the
Specimens used in this study were dry mounted for long-term preservation and examined in the Hymenoptera Unit at the
Morphological terminology follows
The barcoding region of the mitochondrial cytochrome-c oxidase subunit I (CO1) was sequenced for this study (Suppl. material
Leptopilina Förster, 1869: 342, 348 (original description. Type: Cothonaspis longipes Hartig, by monotypy and original designation); Forshage & Nordlander, 2008: 350 (keyed); Novković, Mitsui, Suwito & Kimura, 2011: 337 (phylogenetic relationships of Japanese species); Forshage, Nordlander & Buffington, 2013: 233 (catalog of species of North America); Wachi, Nomano, Mitsui, Kasuya & Kimura, 2015: 48 (phylogenetic relationships); van Noort, Buffington & Forshage, 2015: 64, 73, 90 (diagnosis, keyed, new distribution record for Botswana, Burkina Faso, Burundi, Central African Republic, Ethiopia, Gabon, Ghana, Malawi, Rwanda, Tanzania and Yemen).
Leptopilina are typically small wasps, less than 2mm in length, rather stout when compared with other eucoiline taxa, and have a worldwide distribution. Many species within this genus are easily confused with those in other genera, such as Ganaspis, Kleidotoma, Rhoptromeris, and Trybliographa. However, Leptopilina possess some unique morphological characteristics that allow them to be distinguished from other eucoiline genera. Generally speaking, in Leptopilina, the head narrows ventrally at the bottom of the eyes and forms a triangle. The petiole is enlarged posteriorly, and the broad posterior rim has varying sculptural patterns. The hairy ring at the base of the metasoma is more or less reduced in density with various lengths of setae, but there is no connection dorsally, leading to the common state of ‘hairy ring broken’. The mesoscutum lacks notauli, and the subalar pits are moderately developed.
In Leptopilina, as in all other Eucoilinae, the scutellum is surmounted by a disc with a glandular pit close to the posterior margin of the disc. The posterior margin of the scutellum is usually rounded with punctate sculpture, reticulate sculpture, striate sculpture or a combination of these three. In some species of Leptopilina, the scutellum has ridges radiating from the scutellar disc; this state is similar to some species of Hexacola Föerster, but these Leptopilina can be differentiated by having an incomplete hairy ring on the metasoma (complete hairy ring in most Hexacola) and a glabrous postero-lateral corner of the metapleuron (setose posterolateral corner of metapleuron in Hexacola). Compared to Rhoptromeris, the basal part of the pronotal plate of Leptopilina is distinct and foveae on the pronotal plate are open laterally; by contrast, in Rhoptromeris, but the lateral foveae are closed. Compared to Ganaspis, males have the antennal F1 distinctly modified, whereas the F1 of Leptopilina is shorter than the F2, and F2 is distinctly modified by being curved outward and elongate. This flagellomere character is one of the main characteristics used to separate Leptopilina from Ganaspis. Another important characteristic used to distinguish between Leptopilina and Ganaspis is their metapleural corners: in Leptopilina, the corner is hairless (glabrous), and in Ganaspis, the corner is hairy (setose). Wing morphology can also be helpful in separating other genera from Leptopilina. Leptopilina wings are always covered with short hair, rounded apically, and typically have a long hair fringe on wing tip; the marginal cell is quadrangular in shape and may or may not be closed completely along the anterior margin. In Rhoptromeris the cell is always closed, and more triangular in shape: in Kleidotoma the cell is always open and apical margin is typically emarginate.
Coloration with head, mesosoma, metasoma black to dark brown, legs light brown. Sculpture on vertex, lateral surface of pronotum and mesoscutum absent, surface smooth.
Head, in anterior view, broadly triangular. Pubescence on head sparse setae scattered over face. Sculpture along lateral margin of occiput absent. Gena (measured from compound eye to posterolateral margin of head) short, ratio of length of gena to length of compound eye in dorsal view <0.3. Sculpture of gena absent, smooth. Lateral margin of occiput evenly rounded, not well defined. Occiput (except extreme lateral margin) smooth. Carina issuing from lateral margin of postocciput absent. Ocelli small, ratio of maximum diameter of a lateral ocellus to shortest distance between lateral ocelli 0.2-0.4. Anterior ocellus far from posterior ocelli, clearly separate anterior ocelli to anterior margins of posterior ocelli. Relative position of antennal sockets intermediate, ratio of vertical distance between inner margin of antennal foramen and ventral margin of clypeus to vertical distance between anterior ocellus and antennal rim 2.0-4.0. Median keel absent. Vertical carina adjacent to ventral margin of antennal socket absent but present in L. decemflagella. Facial sculpture absent, surface smooth. Facial impression absent, face flat. Antennal scrobe absent. Anterior tentorial pits small. Vertical delineations on lower face absent. Ventral clypeal margin laterally, close to anterior mandibular articulation straight. Ventral clypeal margin medially with spatulate projection. Clypeus smooth with slight central spatulate projection. Malar space adjacent to anterior articulation of mandible evenly rounded, smooth. Malar sulcus present. Eye removed from ocelli, ratio of distance between compound eye and posterior mandibular articulation to distance between posterior ocellus and compound eye <1.2. Compound eyes, in dorsal view, not distinctly protruding from the surface of the head. Pubescence on compound eyes present, short. Orbital furrows absent. Lateral frontal carina of face absent. Dorsal aspect of vertex smooth. Posterior aspect of vertex smooth. Hair punctures on lateral aspect of vertex absent. Posterior surface of head deeply impressed around postocciput.
Apical segment of maxillary palp with pubescence, consisting one long erect setae. Apical seta on apical segment of maxillary palp longer than twice length of second longest apical seta. Maxillary palp composed of four segments. Last two segments of maxillary palp (in normal repose) straight. Apical segment of maxillary palp more than 1.5 times or 1-1.5 times as long as preceding segment.
Terminal flagellomere with one to three basiconic sensillae. Basiconic sensillae present between F5-F11 and also on F1, F2 in L. maia. Articulation between flagellomeres in antenna moniliform, segments distinctly separated by narrow neck-like articulation. Female antenna composed of 11 flagellomeres, 10 flagellomeres in L. decemflagella. Male antenna composed of 13 flagellomeres. Female F1 longer than F2. Flagellomeres of female antenna cylindrical, distinctly widened towards apex, semi-clavate. Placoidal sensilla present between F5-11. Last antennal flagellomeres of female antenna not conspicuously enlarged compared to adjacent flagellomeres.
Macrosculpture on lateral surface of pronotum absent dorsally and laterally, in L. decemflagella with longitudinal ridge ventrally. Anteroventral inflection of pronotum narrow. Pubescence on lateral surface of pronotum present, sparse long hair. Number of ridges on pronotal plate in lateral view between 2 to 4. Anterior flange of pronotal plate distinctly protruding anteriorly, transversely strigate. Ridges extending posteriorly from lateral margin of pronotal plate distinct but short, not extending to the dorsal margin of pronotum; present. Lateral pronotal carina absent. Crest of pronotal plate absent. Dorsal margin of pronotal plate (in anterior view) spatulate. Submedian pronotal depressions open laterally, deep. Lateral margin of pronotal plate defined all the way to the dorsal margin of the pronotum. Width of pronotal plate narrow, not nearly as wide as head.
Mesoscutal surface convex, evenly curved. Sculpture on mesoscutum absent, entire surface smooth, shiny, with sparse long hairs. Notauli absent. Median mesoscutal carina absent. Anterior admedial lines absent. Median mesoscutal impression absent. Parascutal carina nearly straight.
Mesopleuron entirely smooth. Subpleuron entirely smooth, glabrous. Lower pleuron entirely smooth, glabrous. Epicnemial carina absent. Lateroventral mesopleural carina present, not marking abrupt change of slope of mesopectus. Mesopleural triangle absent. Subalar pit present, located under subalar area obscure to see. Speculum absent. Mesopleural carina present, complete, composed of one complete, uninterrupted carina. Anterior end of mesopleural carina inserting above notch in anterior margin of mesopleuron.
Dorsal surface of scutellum foveate-areolet, areolet - rugulose or irregularly striate. Circumscutellar carina present, complete, delimiting dorsal and ventral halves of scutellum, or incomplete, posteriorly. Posterior margin of axillula marked by distinct ledge, axillula distinctly impressed adjacent to ledge. Latero-ventral margin of scutellum posterior to axillula, smooth or with weakly rugulose. Dorsoposterior part of scutellum rounded. Transverse median carina on scutellar plate absent. Dorsal part of scutellum entirely rugose, foveate, or areolate. Scutellar plate, in dorsal view, medium sized, exposing about half of scutellum. Scutellar fovea present, two, distinctly margined posteriorly. Longitudinal scutellar carinae absent. Single longitudinal carina separating scutellar foveae present, short, ending at posterior margin of foveae. Postero-lateral margin of scutellum rounded. Lateral bar smooth, narrow.
Posterior impression of metepimeron absent or present. Metapectal cavity anterodorsal to metacoxal base present, well-defined. Anterior margin of metapectal-propodeal complex meeting mesopleuron at same level at point corresponding to anterior end of metapleural carina. Posteroventral corner of metapleuron (in lateral view) not extended posteriorly. Anterior impression of metepimeron absent. Posterior margin of metepimeron distinct, separating metepimeron from propodeum. Subalar area broadened anteriorly, narrowed posteriorly. Prespiracular process present, blunt, lobe-like, polished. Dorsellum absent. Anterior impression of metepisternum, immediately beneath anterior end of metapleural carina, present. Pubescence consisting of few hairs on posterior part of metepisternum, few or dense hair on propodeum.
Pubescence posterolaterally on metacoxa, present, small, rounded, with adjacent sparse pubescence. Microsculpture on hind coxa absent. Longitudinal ridge on the posterior surface of metatibia absent. Metafemoral tooth present, elongate, with adjacent serrate ridge posteriorly. Ratio of first metatarsal segment to remaining 4 segments greater than 1.0.
Wing vein M absent or present but not well defined. Pubescence of fore wing present, long, dense on most of surface. Apical margin of female fore wing rounded. Rs+M of forewing defined but nebulous at point of origin from basal vein at posterior third. Mesal end of Rs+M vein situated closer to anterior margin of wing, directed towards middle of basalis. Vein R1 forming marginal cell completely. Basal abscissa of R1 (the abscissa between 2r and the wing margin) of fore wing as broad as adjacent wing veins. Coloration of wing absent, entire wing hyaline. Marginal cell of fore wing membranous, similar to other wing cells. Areolet absent. Hair fringe along apical margin of fore wing present, long or very long.
Propodeal spurs absent. Lateral propodeal carinae present, not reaching scutellum. Ventral end of lateral propodeal carina reaching nucha, carinae separated from each other. Inter propodeal carinae space lightly setose, or too dense to see underlying surface, in L. boulardi with a horizontal carina. Petiolar rim of uniform width along entire circumference. Petiolar foramen removed from metacoxae, directed posteriorly. Horizontal carina running anteriorly from lateral propodeal carina present, or not visible, setae too dense. Lateral propodeal carina, straight, sub-parallel, in L. boulardi distinctly angled. Calyptra, in lateral view, rounded. Propodeum neck-like, drawn out posteriorly. Calyptra, in posterior view, dorsoventrally elongate or rounded.
Petiole about as long as wide. Surface of petiole longitudinally costate, ventral keel absent. Posterior part of female petiole abruptly widened. Ventral and lateral parts of petiolar rim broad.
Setal band (hairy ring) at base of tergum 3 present, interrupted dorsally, ventrally. Tergum 3 indistinct, fused with syntergum. Posterior margin of tergum 3 indistinct, fused with tergum 4 in syntergum. Posterior margin of tergum 4 evenly rounded. Sternum 3 encompassed by syntergum. Sculpture on metasomal terga absent. Syntergum present with terga 3 to 5 fused, ventral margin rounded. Peglike setae on T6–T7 absent. Postero-ventral cavities of female metasoma T7 present, glabrous save for few, long setae. Female postero-ventral margin of T6–T7 straight, parallel. Terebrum and hypopygium (in lateral view) curved, pointing upward. Ovipositor clip, present.
It was difficult to locate type specimens before the revision of
This genus has a worldwide distribution and is known from Europe, Africa, Asia, Australia, North America and South America.
1 | Female with 10 flagellomeres on the antenna (Fig. |
Leptopilina decemflagella Lue & Buffington, sp. n. |
– | Female with 11 flagellomeres (Fig. |
2 |
2 | Mesoscutal hair absent (Figs |
3 |
– | Mesoscutal hair present, sometimes reduced (arrow, Figs |
5 |
3 | Scutellum with semi-parallel to slightly radiating ridges running the length of the dorsal surface of the scutellum, totally lacking foveate-areolet or rugulose pattern (Fig. |
Leptopilina boulardi (Barbotin, Carton & Kelner-Pillault, 1979) |
– | Scutellum with foveate-areolet or rugulose pattern on the dorsal surface of the scutellum (Fig. |
4 |
4 | Scutellar cup large, covering most of the surface of the scutellum, rhomboid shaped (arrow, Figs |
Leptopilina heterotoma (Thomson, 1862) |
– | Scutellar cup smaller, exposing more than half of the dorsal surface of the scutellum, tear-drop in shape (Figs |
Leptopilina victoriae Nordlander, 1980 |
5 | Metapleuron, posteriorly, with a deep depression that is continuous with propodeum (arrow, Fig. |
Leptopilina clavipes (Hartig, 1841) |
– | Metapleuron, posteriorly, not continuous with propodeum but with distinct posterior border (arrow, Fig. |
6 |
6 | Metapleuron, posteriorly, without a deep depression (arrow, Fig. |
Leptopilina leipsi Lue & Buffington, sp. n. |
– | Metapleuron, posteriorly, with a deep depression (arrow, Fig. |
Leptopilina maia Lue & Buffington, sp. n. |
Charips mahensis Kieffer, 1911: 312 (original description); Forshage, Nordlander & Buffington, 2013: 233 (synonym of Leptopilina boulardi (Barbotin, Carton & Kelner-Pillault), type information).
Erisphagia mahensis Kieffer, 1911: 312 (original description).
Cothonaspis (Cothonaspis) boulardi Barbotin, Carton & Kelner-Pillault, 1979: 22 (original description).
Leptopilina boulardi (Barbotin, Carton & Kelner-Pillault): Nordlander, 1980: 432 (generic transfer); Paretas-Martínez, Forshage, Buffington, Fisher, La Salle & Pujade-Villar, 2013: 80 (new distribution record for Australia, listed); Forshage, Nordlander & Buffington, 2013: 233 (cataloged, type information, synonymy); van Noort, Buffington & Forshage, 2015: 92 (listed).
Leptopilina boulardi (Figs
Coloration with head, mesosoma, metasoma black to dark brown, legs light brown. Malar sulcus present, with adjacent groove. Apical segment of maxillary palp more than 1.5 times as long as preceding segment. Terminal flagellomere with two basiconic sensillae. Basiconic sensillae present on F5-F11. Placoidal sensilla present on F6-11. Number of ridges on pronotal plate in lateral view 3. Sculpture on mesoscutum absent, entire surface smooth, shiny. Dorsal surface of scutellum irregularly striate, space between striate smooth. Circumscutellar carina present, incomplete, laterally delimiting dorsal and ventral halves of scutellum, not present posteriorly. Latero-ventral margin of scutellum posterior to axillula entirely smooth. Dorsal part of scutellum entirely rugose. Scutellar plate, in dorsal view, medium sized, exposing about half of scutellum. Posterior impression of metepimeron absent. Anterior impression of metepisternum, immediately beneath anterior end of metapleural carina, present, small and narrow. Pubescence consisting of few scattered hairs on posterior part of metapleuron and lateral part of propodeum. Wing vein M: absent. Inter propodeal carinae space smooth with a horizontal carina. Horizontal carina running anteriorly from lateral propodeal carina not visible, setae too dense. Lateral propodeal carina distinctly angled. Surface of petiole longitudinally costate, ventral keel absent. Setal band (hairy ring) at base of tergum 3 present, few scattered hairs.
Maryland, Virginia, South Carolina, and Florida. [http://hol.osu.edu/map-full.html?id=323700]
United States. FL, Leon Co., 30.580557°N 84.277435°W, Tallahassee Site, 14.X-18.X.2013, bait trap, C.-H. Lue (46 females, USNMENT00917557, 00917581, 00917596, 00917608, 00917618, 00917634, 00917640, 00917645, 00917672, 00917686, 00917717, 00917723, 00917726-00917727, 00917734-00917736, 00917766, 00917822, 00917827, 01022149, 01022151, 01022210, 01022219, 01022254, 01022303, 01022371, 01022385, 01022409, 01022439-01022440, 01022473, 01022483, 01022500, 01022521, 01022610, 01022619, 01022660, 01022710, 01022730, 01022756, 01022769, 01022785, 01022860, 01022887, 01022974 (
Cothonaspis clavipes Hartig, 1841: 357 (original description); Nordlander, 1978: 50 (lectotype designation).
Leptopilina clavipes (Hartig): Nordlander, 1980: 430 (generic transfer, description); van Alphen, Nordlander & Eijs, 1991: 325 (diagnosis); Forshage, Nordlander & Buffington, 2013: 233 (cataloged, type information).
Leptopilina clavipes (Figs
Coloration with head, mesosoma, metasoma black to dark brown, legs light brown. Malar sulcus present. Apical segment of maxillary palp 1-1.5 times as long as preceding segment. Placoidal sensilla present on F5-11. Number of ridges on pronotal plate in lateral view 4. Sculpture on mesoscutum absent, with sparse long hairs. Dorsal surface of scutellum foveate-areolet. Circumscutellar carina present, incomplete, laterally delimiting dorsal and ventral halves of scutellum, not present posteriorly. Latero-ventral margin of scutellum posterior to axillula almost entirely smooth, weakly rugulose dorsally. Dorsal part of scutellum entirely areolate. Scutellar plate, in dorsal view, medium sized, exposing about half of scutellum. Lateral bar weakly strigate, narrow. Posterior impression of metepimeron present and well defined. Posterior margin of metepimeron distinct, has a strong impression continuous posterior propodeum. Anterior impression of metepisternum, immediately beneath anterior end of metapleural carina, present, large and wide. Wing vein M absent. Inter propodeal carinae space lightly setose, smooth. Horizontal carina running anteriorly from lateral propodeal carina not visible, setae too dense. Surface of petiole dorsally and laterally striate, ventral keel absent. Setal band (hairy ring) at base of tergum 3 present, interrupted dorsally, ventrally, dense hair.
Maine, New Hampshire, Massachusetts, Illinois, Maryland, Virginia, South Carolina, and Florida. [http://hol.osu.edu/map-full.html?id=323705]
United States. FL, Leon Co., 30.580557°N 84.277435°W, Tallahassee Site, 12.VI-17.VI.2013, yellow pan trap, C.-H. Lue (2 females, USNMENT01022195, 01022765 (
Female Leptopilina decemflagella (Figs
Coloration with head, mesosoma, metasoma black, legs light brown. Vertical carina adjacent to ventral margin of antennal socket present. Malar sulcus present. Apical segment of maxillary palp more than 1.5 times as long as preceding segment. Terminal flagellomere with three basiconic sensillae. Basiconic sensillae present on F5-F10. Female antenna composed of 10 flagellomeres. Placoidal sensilla present on F6-10. Number of ridges on pronotal plate in lateral view 3. Sculpture on mesoscutum absent, entire surface smooth, shiny. Subpleuron entire smooth, anteriorly with transversely striate. Dorsal surface of scutellum foveate-areolet. Circumscutellar carina present, incomplete, laterally delimiting dorsal and ventral halves of scutellum, not present posteriorly. Latero-ventral margin of scutellum posterior to axillula entirely smooth. Dorsal part of scutellum entirely areolate. Scutellar plate, in dorsal view, medium sized, exposing about half of scutellum. Posterior impression of metepimeron absent. Anterior impression of metepisternum, immediately beneath anterior end of metapleural carina, absent. Wing vein M present but not well defined. Inter propodeal carinae space setose, too dense to see underlying surface. Horizontal carina running anteriorly from lateral propodeal carina, present. Surface of petiole longitudinally costate, ventral keel absent. Setal band (hairy ring) at base of tergum 3 present ventrolaterally, absent dorsally and ventrally. Terebrum and hypopygium (in lateral view) curved, pointing ventrally.
Florida. [http://hol.osu.edu/map-full.html?id=410492]
The name Leptopilina decemflagella is based on the 10 flagellomeres of the female antenna. This feature is unique among female North American Leptopilina which all have 11 flagellomeres. We treat this name is a noun in apposition.
Leptopilina decemflagella, shares some unique morphological characters with L. tsushimaensis Wachi and Kimura, 2015, a species described from Japan. These characters include an antenna with only 10 flagellomeres, and the presence of a vertical carina adjacent to the ventral margin of the antenna socket. However, the vertical carinae adjacent to the toruli in L. decemflagella do not extend to the mid-point of the eye (when viewed anteriorly); in L. tsushimaensis, the carinae extend to the mid-point of the eye. Furthermore, the clava in L. decemflagella is clearly five segmented, and the claval segments are about as long as wide; in L. tsushimaensis, the clava is six segmented, and each segment is longer than wide. Flagellomere 5 in L. decemflagella is the transition flagellomere between claval and non-claval portions of the antenna, and results in rather gradually defined clava; in L. tsushimaensis, flagellomere 5 is the first full claval segment, and there is no transitional segment, resulting in an abruptly defined clava. Finally, the COI barcode region was sequenced for L. tsushimaensis, and this data suggests more than a 5% divergence from L. decemflagella (data not presented). Ergo, we feel we have ample evidence to describe L. decemflagella as a distinct species from L. tsushimaensis.
Holotype. Leptopilina decemflagella female: United States. FL, Miami-Dade Co., 25.534444°N 80.492863°W, Homestead, 26.V-28.V.2013, bait trap, C.-H. Lue, USNMENT00917604 (deposited in
Eucoila heterotoma Thomson, 1862: 403 (original description); Nordlander, 1978: 50 (lectotype designation).
Ganaspis subnuda Kieffer, 1904: 64 (original description); Forshage, Nordlander & Buffington, 2013: 233 (junior synonym of Leptopilina heterotoma (Thomson), type information).
Ganaspis monilicornis Kieffer, 1905: 623 (original description); Weld, 1952: 228 (junior synonym of Ganaspis musti).
Erisphagia philippinensis Kieffer, 1916: 282 (original description).
Pseudeucoila (Pseudeucoila) bochei Weld, 1944: 65-66 (original description).
Cothonaspis (Erisphagia) philippinensis (Kieffer): Weld, 1952: 244 (generic transfer).
Pseudeucoila bochei Weld: Nøstvik, 1954: 142 (description of early developmental stages); Forshage, Nordlander & Buffington, 2013: 233 (junior synonym of Leptopilina heterotoma (Thomson), type information).
Leptopilina monilicornis (Kieffer): Nordlander, 1980: 430 (removed from synonymy with G. musti and entered into synonymy with Leptopilina heterotoma).
Leptopilina philippinensis (Kieffer): Nordlander, 1980: 430 (junior synonym of Leptopilina heterotoma, lectotype designation).
Leptopilina subnuda (Kieffer): Nordlander, 1980: 430 (junior synonym of Leptopilina heterotoma).
Leptopilina bochei (Weld): Nordlander, 1980: 431 (junior synonym of Leptopilina heterotoma).
Leptopilina heterotoma (Thomson): Nordlander, 1980: 430 (generic transfer); Paretas-Martínez, Forshage, Buffington, Fisher, La Salle & Pujade-Villar, 2013: 80 (new distribution record for Australia, listed); Forshage, Nordlander & Buffington, 2013: 233 (cataloged, type information, synonymy); Ward, 2014: 575 (keyed); van Noort, Buffington & Forshage, 2015: 92 (listed).
Leptopilina heterotoma (Figs
Coloration with head, mesosoma, metasoma black to dark brown, legs light brown. Malar sulcus present. Apical segment of maxillary palp 1–1.5 times as long as preceding segment. Terminal flagellomere with two basiconic sensillae. Basiconic sensillae present on F6–F11. Placoidal sensilla present on F6–F11. Number of ridges on pronotal plate in lateral view 3. Sculpture on mesoscutum absent, entire surface smooth, shiny. Parascutal carina curved mesally. Dorsal surface of scutellum areolet - rugulose. Circumscutellar carina present, incomplete, laterally delimiting dorsal and ventral halves of scutellum, not present posteriorly. Latero-ventral margin of scutellum posterior to axillula smooth ventrally, weakly rugulose dorsally. Dorsal part of scutellum entirely rugose. Scutellar plate, in dorsal view, large, rhombus shape, covering most of scutellum. Posterior impression of metepimeron absent. Anterior impression of metepisternum, immediately beneath anterior end of metapleural carina, present, small and narrow. Wing vein M absent. Inter propodeal carinae space setose, too dense to see underlying surface. Horizontal carina running anteriorly from lateral propodeal carina not visible, setae too dense. Surface of petiole longitudinally costate laterally, shagreen dorsally. Setal band (hairy ring) at base of tergum 3 present, interrupted dorsally, ventrally, dense hair.
Maryland and Virginia. [http://hol.osu.edu/map-full.html?id=323709]
United States. MD, Baltimore Co., 39.668081°N 76.578860°W, White Hall Site, 17.VI.2012, bait trap, C.-H. Lue (5 females, USNMENT00917851, 00917918, 00917956, 00917980, 00917998 (
Leptopilina leipsi (Figs
Coloration with head, mesosoma, metasoma black to dark brown, legs light brown. Malar sulcus present. Apical segment of maxillary palp 1–1.5 times as long as preceding segment. Terminal flagellomere with one basiconic sensillum. Basiconic sensillae present on F5–F11. Placoidal sensilla present on F5-11. Number of ridges on pronotal plate in lateral view 2. Sculpture on mesoscutum absent, with sparse long hairs. Dorsal surface of scutellum foveate-areoletate. Circumscutellar carina present, incomplete, laterally delimiting dorsal and ventral halves of scutellum, not present posteriorly. Latero-ventral margin of scutellum posterior to axillula smooth ventrally, weakly rugulose dorsally. Dorsal part of scutellum entirely foveate. Scutellar plate, in dorsal view, small to medium sized, exposing small part of scutellum. Posterior impression of metepimeron present but not well defined. Anterior impression of metepisternum, immediately beneath anterior end of metapleural carina, present, small and narrow. Wing vein M absent. Inter propodeal carinae space setose, too dense to see underlying surface. Horizontal carina running anteriorly from lateral propodeal carina not visible, setae too dense. Surface of petiole longitudinally costate, ventral keel absent. Setal band (hairy ring) at base of tergum 3 present, interrupted dorsally, ventrally, longer hairs at ventral part.
New Hampshire, Illinois, Maryland, and Virginia. [http://hol.osu.edu/map-full.html?id=417663]
Leptopilina leipsi is named in honor of Dr. Jeff Leips (the PhD advisor of Lue) in appreciation for his support of her dissertation project.
Holotype. Leptopilina leipsi female: United States. MD, Baltimore Co., 39.668081°N 76.578860°W, White Hall Site, 1.X-4.X.2013, yellow trap, C.-H. Lue, USSMENT01022612 (deposited in
Leptopilina maia (Figs
Coloration with head, mesosoma, metasoma black to dark brown, legs light brown. Malar sulcus present, with adjacent groove. Apical segment of maxillary palp 1–1.5 times as long as preceding segment. Terminal flagellomere with one basiconic sensillum. Basiconic sensillae present on F1, F2, and F5–F11. Placoidal sensilla present on F5–11. Number of ridges on pronotal plate in lateral view 2. Sculpture on mesoscutum absent, with sparse long hairs. Dorsal surface of scutellum foveate-areolet. Circumscutellar carina present, complete, delimiting dorsal and ventral halves of scutellum. Latero-ventral margin of scutellum posterior to axillula entirely smooth. Dorsal part of scutellum entirely areolate. Scutellar plate, in dorsal view, small or medium sized, exposing small part of scutellum. Posterior impression of metepimeron present but not well defined. Anterior impression of metepisternum, immediately beneath anterior end of metapleural carina, present, small and narrow. Wing vein M present but not well defined. Inter propodeal carinae space setose, too dense to see underlying surface. Horizontal carina running anteriorly from lateral propodeal carina not visible, setae too dense. Surface of petiole longitudinally costate, ventral keel absent. Setal band (hairy ring) at base of tergum 3 present, interrupted dorsally, ventrally, dense hair.
Maine, New Hampshire, Illinois, Arkansas, Massachusetts, Connecticut, Pennsylvania, Maryland, Virginia, North Carolina, and Florida. [http://hol.osu.edu/map-full.html?id=417662]
Leptopilina maia is named in honor of the mother of the first author. The name maia means ‘mother’ in Greek form. Here we also use maia is to show our appreciation for Mother Nature and also the women who nurtured us growing up. Moreover, parasitoids, in general, are good mothers that have amazing strategies to find suitable hosts for their offspring. This name is a noun in apposition.
Holotype. Leptopilina maia female: United States. MD, Baltimore Co., 39.668081°N 76.578860°W, White Hall Site, 19.VI.2012, yellow pan trap, C.-H. Lue, USNMENT01022751 (deposit in
Leptopilina victoriae Nordlander, 1980: 447 (original description); Novković, Mitsui, Suwito & Kimura, 2011: 344 (new distribution record from Japan, Indonesia and Malaysia, host association); van Noort, Buffington & Forshage, 2015: 92 (listed).
The shape of antenna and metasoma of Leptopilina victoriae is similar to L. boulardi. However, the two species can be easily separate by the patterns of the scutellum (Figs
Coloration with head, mesosoma, metasoma black to dark brown, legs light brown. Malar sulcus present. Apical segment of maxillary palp more than 1.5 times as long as preceding segment. Terminal flagellomere with three basiconic sensillae. Basiconic sensillae present on F6–F11. Placoidal sensilla present on F7–11. Number of ridges on pronotal plate in lateral view 2. Sculpture on mesoscutum absent, entire surface smooth, shiny. Dorsal surface of scutellum areolet - rugulose. Circumscutellar carina present, complete, delimiting dorsal and ventral halves of scutellum. Latero-ventral margin of scutellum posterior to axillula smooth ventrally, weakly rugulose dorsally. Dorsal part of scutellum entirely areolate. Scutellar plate, in dorsal view, medium sized, exposing about half of scutellum. Posterior impression of metepimeron absent. Anterior impression of metepisternum, immediately beneath anterior end of metapleural carina, present, small and narrow. Wing vein M present but not well defined. Inter propodeal carinae space lightly setose, smooth. Horizontal carina running anteriorly from lateral propodeal carina, absent. Surface of petiole longitudinally costate, ventral keel absent. Setal band (hairy ring) at base of tergum 3 present, interrupted dorsally, ventrally, dense short hair.
Of the seven species in our identification key, L. victoriae did not appear in our field collections. However, because this species is commonly used in laboratory experiments we include this species in the identification key to assist with diagnosis of other Leptopilina species that are also commonly used as laboratory strains (e.g., L. boulardi, L. heterotoma and L. clavipes).
Paratypes (2 females, 2 males, BMNH): Strain G 311-1, Seychelles. G.
Species of Leptopilina have been studied as Drosophila parasitoids for over five decades. However, knowledge of their natural history and taxonomic information remains limited for most species. None of this is too surprising when one considers the difficulties associated with identifying Leptopilina species. The cryptic morphological features among species, combined with geographic variation within species, could lead to the misidentification or description of species in this genus. Here we provide a key for identifying seven North American Leptopilina species associated with frugivorous hosts and within this group, describe three new species: Leptopilina decemflagella sp. n., L. maia sp. n., and L. leipsi n.sp. In addition to describing morphological characters that can be used for diagnosis, we also provide sequence data on CO1 for each species, in part to evaluate to what extant morphological divergence is reflected at the sequence level.
Molecular markers can be useful for distinguishing operational taxonomic units, especially for very small organisms that are difficult to separate morphologically due to their cryptic nature, or when species exhibit extensive intraspecific morphological variation. However, the high-efficiency associated with gathering sequence data poses a possible trade-off in accuracy for species that lack diagnostic data and/or lack trained taxonomists to develop character-based analysis to verify the molecular signal (
The ideal use of DNA barcoding for species identification is to complement the sequence data with other sources of information (
Although the large size of our collection captures variation and allows us to identify diagnostic characters for most groups, difficulties delimiting cryptic species are still present in this study. In our collections some morphological characteristics (e.g., body size, scutellum size and ridge patterns on the metapleura) show high intraspecific variation but low interspecific divergence, and as a consequence, fail to consistently delimit species. For example, three Leptopilina species share similar morphological characters and habitats in this study, L. clavipes, L. maia and L. leipsi and the scutellum pattern, body size, and morphological characters that we commonly used to delimit other Leptopilina species, fail to discriminate L. maia from L. leipsi. We had to complement the consistent morphological characters (see results) with 5% genetic divergence in the CO1 sequence to be confident in assigning them to different species.
Two complicating factors often make it difficult to discriminate species in this group. First, parasitoid wasps often have limited ranges and small population size. As a result, parasitic life style can accelerate the rate of mitochondrial genetic divergence (
This study is the first of its kind in North America, and in three ways, the first of its kind for Leptopilina. First, historically important museum specimens were augmented by specimens comprehensively collected across the Drosophila host breeding season and also across a broad geographic scale. Sampling across this geographic scale, and obtaining a large sample of individuals at each location throughout the breeding season, allowed us to account for intraspecific variation among Leptopilina when delimiting the species, something not possible when using a smaller pool of specimens. Consequently, we are able to describe morphological variation at the lowest taxonomic level. This is important because phenotypic variation is one of the main factors that reflects rapid evolution of parasitoid wasps. Within the framework of this new collecting paradigm, we also collected potential hosts at the same time we collected parasitoid wasps (Lue et al. in preparation). Secondly, sorting bulk, passively collected samples for Leptopilina, as well as direct rearing, allowed us to discover three new species. Finally, we consider this study especially critical at the present time, as the invasive Spotted Wing Drosophila (SWD; Drosophila suzukii Matsumura) has spread rapidly on the east coast of the US (
We gratefully acknowledge the support of the owners of One Straw Farm, Weber Farm, Robert Is Here, Fruit and Spice Park, Orchard Pond Organic Farm and Musser Fruit Research Farm for allowing us to sample on their property. We thank Dr. Todd Schlenke, Dr. Masahito Kimura and Dr. Mattias Forshage for providing personal parasitoid collections for reference samples. We thank Dr. Kenneth MacDonald for his assistance with molecular work. We thank Dr. Norm Johnson and Sara Hemly (OSU) for assistance using vSyslab. We also thank Dr. Elijah Talamas for advise with image processing in the Hymenoptera Imaging Suite at the
Percent sequence difference among Leptopilina species.
Data type: measurement
Explanation note: Percent sequence difference among species at the barcode region of the cytochrome oxidase subunit I gene. Values in bold are the percent sequence difference within each species. Sample sizes are in parentheses in the left-most column. The asterisk indicates the newly described species of Leptopilina.