Research Article |
Corresponding author: Shunpei Fujie ( shunpei.fujie@gmail.com ) Academic editor: Kees van Achterberg
© 2022 Shunpei Fujie, Kaoru Maeto.
This is an open access article distributed under the terms of the CC0 Public Domain Dedication.
Citation:
Fujie S, Maeto K (2022) The genus Aridelus Marshall (Hymenoptera, Braconidae, Euphorinae) from Japan, with description of a new species. ZooKeys 1092: 105-122. https://doi.org/10.3897/zookeys.1092.73299
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Six Japanese species belonging to the genus Aridelus Marshall, 1898 (Hymenoptera, Braconidae) were recorded and photographed. Three species, A. dubius Belokobylskij, A. egregius Schmiedeknecht and A. rufotestaceus Tobias (= Aridelus rufiventris Luo & Chen syn. nov.), are new to Japan, and a new species, A. rutilipoides sp. nov. is described. An identification key to the Japanese species of Aridelus is also provided. In addition, new host records are provided, i.e., A. flavicans Chao reared from Homoeocerus unipunctatus and Riptortus pedestris (Alydidae) and A. rufotestaceus reared from Glaucias subpunctatus (Pentatomidae). The Alydidae is a newly recorded host family of Aridelus.
Aridelus, host records, identification key, new species, stink bug parasitoids, taxonomy
The braconid subfamily Euphorinae is unique in attacking a wide range of host orders, including both larvae and adult insects (
The genus Aridelus Marshall, 1887 has an aberrant morphology, that is, the entirely areolate mesosoma and the elongated tubular first metasomal tergite. Using a petiolated metasoma with a short ovipositor, females lay eggs into nymphs or adults of heteropteran stink bugs (
In our study of Japanese Euphorinae, we identified six species of Aridelus, that is, A. dubius Belokobylskij, 1981, A. egregius (Schmiedeknecht, 1907), A. elasmuchae, A. flavicans, A. rufotestaceus Tobias, 1986, and A. rutilipoides sp. nov. In this study, all Japanese species are photographed, a new species is described, and an identification key to the Japanese species is provided. In addition, new host records of A. flavicans and A. rufotestaceus are presented herein.
The specimens examined were deposited in Kanagawa Prefectural Museum of Natural History, Odawara, Japan (
Morphological observation was conducted using a stereoscopic microscope (SMZ800N, Nikon, Tokyo, Japan). The specimens were photographed using a digital microscope (VHX-1000, Keyence, Osaka, Japan) with a 10–130× lens. Multi-focus photographs were stacked in the software associated with the Keyence System. The figures were edited using Microsoft PowerPoint 2019.
The morphological terminology used is mostly based on
Aridelus
Marshall, 1887: 66;
(by monotypy). Aridelus bucephalus Marshall, 1887.
Head transverse; antenna filiform or moniliform, with 18 segments, its terminal segment with an apical spine; maxillary palp with 6 segments; labial palp with 4 segments; occipital carina complete or absent mediodorsally for a long distance, rarely completely absent, ventrally joining hypostomal carina; frons punctate or smooth with a median carina extending to frontal ocellus; face wider than clypeus in female; lower clypeal margin usually indented medially, rarely rounded; malar suture usually absent; mandibles overlapping each other; mesonotum, mesopleuron, and propodeum mostly areolate; petiolar notch extending nearly to mesocoxal insertions; parastigma large; vein 1-SR of fore wing absent to rarely shortly present and thickened; vein 3-SR of fore wing absent to distinctly present; vein 1-R1 of fore wing short; end of vein SR1 of fore wing much closer to pterostigma than to apex of wing; vein r-m of fore wing present; veins SR and 2-M of hind wing present, darkly pigmented; first metasomal tergite about 3/4 times as long as remainder of metasoma and completely fused ventrally; third tergite nearly reaching end of metasoma, following segments hidden; second and third tergites ventrally overlapping, without lateral fold; ovipositor and its sheath shortly exposed.
Cosmopolitan and the most diverse in tropical regions (
Endoparasitoids of nymphs and adults of Acanthosomatidae, Pentatomidae, Plataspidae, and Scutelleridae (
1 | Median carina of frons only weakly developed (Fig. |
A. egregius (Schmiedeknecht) |
– | Median carina of frons distinct (Figs |
2 |
2 | Head yellow, yellowish red, yellowish brown or reddish brown (Figs |
3 |
– | Head black (Figs |
5 |
3 | First metasomal tergite pale yellow, distinctly contrast to blackish or dark brownish second and following tergites (Fig. |
A . elasmuchae Maeto & Kudo |
– | First metasomal tergite yellowish red to reddish brown, not distinctly contrasting to second and following tergites (Figs |
4 |
4 | Vertex punctate and without transverse rugae (Fig. |
A. flavicans Chao |
– | Vertex punctate, often transversely rugose (Fig. |
A. rufotestaceus Tobias |
5 | Penultimate segment of antenna 1.2–1.3 times as long as its width (Fig. |
A. rutilipoides sp. nov. |
– | Penultimate segment of antenna 1.6–1.7× longer than wide (Fig. |
A. dubius Belokobylskij |
Aridelus dubius Belokobylskij, 1981: 44. [Type locality: Russia]
Japan Honshû: 1♀, Niigata Pref., Myoukou City, Suginosawa, Sasagamine, 36-52N/138-4E, about 1200–1335 m alt., 18.IX.2013, S. Shimizu leg. (
Females (N = 3) (Fig.
Head
(Fig.
Mesosoma. Mesosoma areolate, 1.3× as long as high. Scutellum without median smooth area.
Wings
(Fig.
Legs
(Fig.
Metasoma. Metasoma smooth and polished. First metasomal tergite 6.0× longer than its apical width. Hypopygium truncated and excised apically. Ovipositor sheath hardly exserted beyond apex of metasoma.
Colour. Black. Palpi, antenna entirely, mandible, tegula, legs except for telotarsus and first metasomal tergite dark reddish brown; remainder of metasoma reddish brown, telotarsus and veins dark brown; pterostigma pale in basal 1/5 or faintly pale basally. Fore wing hyaline with two fuscous bands. Hind wing with a fuscous band in its apical third.
Japan (Honshû: Niigata and Hiroshima Prefectures); Russian Far East (
Unknown.
This species was described with only the male holotype available. The Japanese specimens mostly agree well with the original description (
This species resembles A. rutilipes Papp described from Taiwan (Fig.
Helorimorpha egregia Schmiedeknecht, 1907: 523. [Type locality: Germany]
Aridelus egregia
(Schmiedeknecht):
Aridelus nigricans
Chao, 1974: 455. Syn. by
Aridelus destitutus
Chou, 1987: 26. Syn. by
Japan Honshû: 1♀, Tôkyô Pref., Chiyoda Ward, Imperial Palace, Fukiagegyoen, Kajuen, 14–21.X.2009, MsT. (NSMT); 1♀, Fukui Pref., Tsuruga City, Marsh of Nakaikemi, 19.IX–16.X. 2016, MsT., A. Noishiki leg. (
Japan (Honshû: Tôkyô and Fukui Prefectures; Kyûshû: Ôita Prefecture); Western Palaearctic region; China, Korea, Russian Far East, Taiwan (
No host records are available in Japan, while Pentatomidae (Aelia, Dolycoris, Eurydema, Holcostethus, Palomena) (
Aridelus elasmuchae Maeto & Kudo, 1992: 78. [Type locality: Japan]
Japan Hokkaidô: 1♀, holotype, Nopporo, 15.VII.1986, S. Kudô leg. (NARO); 2♂♂, Sapporo City, Hitsujigaoka, 20–27.VI.2011, MsT., K. Konishi leg. (
Japan (Hokkaidô; Honshû: Aomori, Miyagi, Tochigi, Toyama, Hyôgo and Tottori Prefectures; Shikoku: Ehime Prefecture; Kyûshû: Ôita Prefecture) (
Elasmucha putoni Scott, 1874 (Acanthosomatidae) (
Aridelus flavicans
Chao, 1974: 455;
Aridelus guizhouensis
Luo, 1985: 203. Syn. by
Japan Honshû: 1♀, Aomori Pref., Aomori City, Yokouchi-Yaegiku, 11.IX.1993, T. Ichita leg. (NARO); 1♂, Tôkyô Pref., Hachiôji City, Minamiôsawa, Tôkyô Metropolitan University, 10.VIII.2010, N. Kikuchi leg. (
Japan (Honshû: Aomori, Tôkyô, Nara, Ôsaka, Hyôgo, Tottori and Hiroshima Prefectures; Kyûshû: Fukuoka and Ôita Prefecture) (
Homoeocerus unipunctatus (Thunberg, 1783) (Alydidae) feeding on Pueraria lobata (Fabaceae) and Riptortus pedestris (Linnaeus, 1758) (Alydidae) on Phaseolus vulgaris (Fabaceae) (both new records). The family Alydidae is the first record of the host of the genus Aridelus.
The female specimens examined agree well with the redescription by
Aridelus rufotestaceus
Tobias, 1986: 229 (English translation: 399);
Aridelus rufiventris
Luo & Chen, 1994: 483;
Russia 1♀, holotype, Lazarevskoe, Sochi, forest along rivulet, 14.IX.1981, V. Tobias leg. (
Japan (Honshû: Shizuoka, Toyama, Mie and Kyôto Prefecture; Hachijôjima Is.; Kyûshû: Kumamoto Prefecture; Yakushima Is.); China, Georgia, Korea, Italy, Russian Far East (
Glaucias subpunctatus (Walker, 1867) (a new record) and Nezara viridula (Linnaeus, 1758) (
Holotype
, ♀, “(JAPAN) Nagano Pref., Ueda City, Sugadaira-kougen, Tsukuba Univ., 36-31N/138-20E, about 1300 m alt., 13 IX 2013 (sweeping), Sou Shimizu leg.” (
Named after its similarity to A. rutilipes Papp. The Latin suffix –“oides” taken from Greek means similar but not the same.
Female holotype (Fig.
Head
(Fig.
Mesosoma
(Fig.
Wings
(Fig.
Legs
(Fig.
Metasoma
(Fig.
Colour. Black. Antenna basally, mandible medially, palpi, tegula, legs except for telotarsus, metasoma reddish brown; mandible basally and apically, veins, telotarsus dark brown, antenna gradually darkened towards apex; pterostigma pale in basal quarter. Fore wing hyaline with two fuscous band. Hind wing with a fuscous band in apical third.
Variation in females. Body length 5.8–6.5 mm. Length of eye 1.2–1.4× length of temple in dorsal view; OOL / OD = 3.5–4.1. POL / OD = 1.5–1.9. Face 1.7–1.9× as wide as high. Intertentorial distance / tentorio-ocular distance = 1.7–1.9. Length of malar space 0.5–0.6× eye height. Malar suture indistinct or absent. Third antennal segment 3.5–4.0× longer than wide and 1.2–1.4× longer than 4th one; penultimate one 1.2–1.3× longer than wide. Mesosoma length 1.3–1.4× height. Fore wing 4.8–5.2 mm in length, 1-R1 / length of pterostigma = 1.2–1.5, r / 3-SR = 2.2–3.6. Hind wing with 1r-m / 2-SC+R = 0.8–1.0. Hind leg: femur 4.6–5.2× longer than wide, length of femur: tibia: basitarsus = 1: 1.3–1.4: 0.6. First metasomal tergite 5.9–6.3× longer than its apical width.
Male. Unknown.
Japan (Hokkaidô; Honshû: Nagano Prefecture; Shikoku: Tokushima Prefecture).
Unknown.
This species closely resembles A. rutilipes Papp (Fig.
Among the six Japanese species, A. egregius and A. rufotestaceus are widely distributed in the Palaearctic region, but four other species (A. dubius, A. elasmuchae, A. flavicans, and A. rutilipoides sp. nov.) are virtually confined to East Asia (China, Japan, Korea, the Russian Far East and Taiwan). Two Japanese species, A. rutilipoides sp. nov. and A. dubius, have a comparatively larger body and the fore wing with two fuscous bands and belong to a species complex with A. rutilipes from continental China, Korea, and Taiwan, and A. ussuriensis from continental China, Korea, and the Russian Far East. A comprehensive study on the fauna and phylogeny of Aridelus in and around East Asia is required.
All previously known host families of Aridelus (Acanthosomatidae, Pentatomidae, Plataspidae, Scutelleridae) belong to the superfamily Pentatomoidea (
SF is grateful to Masato Ito, Ryudai Ito, Namiki Kikuchi, Kazunori Matsuo, Asato Noishiki, So Shimizu and Hiroko Yamasaki for collecting and offering the studied specimens. We are grateful to Sergey Belokobyskij, Tatsuya Ide, Rikio Matsumoto, Konstantin Samartsev, Kyohei Watanabe, Kenzo Yamagishi and Junsuke Yamasako for the investigation of the materials. We also thank to Sergey Belokobyskij, Julia Stigenberg and Kees van Achterberg for useful comments. This research is partially supported by the Grants-in-Aid for JSPS KAKENHI (Grant number 19H00942) to KM.
Table S1
Data type: xlsx file
Explanation note: Comparison of Chinese specimens of Aridelus rufotestaceus Tobias and A. rufiventris Luo & Chen with Japanese and Korean specimens of A. rufotestaceus.