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ISSN : 1225-0171(Print)
ISSN : 2287-545X(Online)
Korean Journal of Applied Entomology Vol.65 No.1 pp.65-71
DOI : https://doi.org/10.5656/KSAE.2026.01.1.068

Checklist of Korean Megastigmus Dalman (Hymenoptera: Megastigmidae) with Two New Records

Duk-Young Park1, Seunghwan Lee1,2*
1Insect Biosystematics Laboratory, Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Korea
2Research Institute of Agricultural and Life Sciences, Seoul National University, Seoul 08826, Korea
*Corresponding author:seung@snu.ac.kr
December 2, 2025 January 19, 2026 January 22, 2026

Abstract


Two previously unrecorded species of the genus Megastigmus are newly recognized from South Korea: M. aculeatus (Swederus, 1795) and M. rigidae Xu & He, 1998. These two species emerged from the seeds of Rosa multiflora Thunb. and Juniperus rigida Siebold & Zucc., respectively. In the present study, a key to Korean species of Megastigmus, a diagnosis and a redescription are provided along with the images of diagnostic characters.


측백나무과 , 장미과 , 구북구 , 식식성 , 종자 섭식

미기록 2종을 포함한 한국산 왕꼬리좀벌속 (벌목: 왕꼬리좀벌과)의 종 목록

박덕영1, 이승환1,2*
1서울대학교 농생명공학부 곤충계통분류학 실험실
2서울대학교 농업생명과학연구원

초록


본 연구에서는 한국산 왕꼬리좀벌속의 미기록종인 장미왕꼬리좀벌(신칭)과 노간주왕꼬리좀벌(신칭)을 처음으로 보고한다. 이 두 종은 각각 찔레 종자와 노간주나무 종자에서 우화하였다. 본 논문에서는 한국산 왕꼬리좀벌속의 검색표와 진단형질, 재기재문 및 사진을 제공한다.


측백나무과 , 장미과 , 구북구 , 식식성 , 종자 섭식

    Megastigmidae is distributed worldwide, with approximately 200 species across 14 valid genera and the highest diversity in the Australian region (Janšta et al., 2018;UCD Community, 2025). Among these genera, Megastigmus is the only one with a cosmopolitan distribution, primarily in the Holarctic region.

    Most species of Megastigmus are known as seed feeders associated with plants belonging to 11 orders, although the exact number of host plant species remains unclear, while a small number of species act as parasitoids of gall-making insects (UCD Community, 2025). To date, approximately 140 species of Megastigmus have been recorded worldwide, with 12 species reported from Japan and 17 species from China (UCD Community, 2025).

    In South Korea, however, only two species (M. inamuraeYano, 1918 and M. borriesiCrosby, 1913) have previously been recorded (Paik, 1974, 1978;Roques and Skrzypczyńska, 2003). In the present study, two additional species, M. aculeatus and M. rigidae, are newly recorded from South Korea, increasing the known Korean fauna of the genus to four species.

    Materials and Methods

    Fruits of Rosa multiflora and Juniperus rigida were collected in the field from winter to early spring and transferred to the laboratory, where they were kept at room temperature. A single adult emerged from each seed. Emerged adults were preserved in 95% ethanol, and some specimens were prepared as dried mounts for morphological examination. The examined specimens are deposited at the Laboratory of Insect Biosystematics, Seoul National University (SNU), and one specimen is deposited in the National Institute of Biological Resources (NIBR). Most morphological terms follow Roques and Skrzypczyńska (2003).

    Specimens were examined with an Olympus SZ61 stereomicroscope (Olympus Corporation, Tokyo, Japan) and photographed with a DMC 5400 digital camera (Leica Microsystems GmbH, Wetzlar, Germany) attached to a Leica Z16 APO motorized macroscope (Leica Microsystems GmbH, Wetzlar, Germany). Serial images were combined using Zerene Stacker (Zerene Systems LLC, Richland, WA, USA) and digitally retouched using Adobe Photoshop CS6 (Adobe Inc., San Jose, CA, USA).

    Acronyms and abbreviations used in this paper are as follows: MNHN, Muséum National d'Histoire Naturelle, Paris, France; NHMV, Naturhistorisches Museum, Vienna, Austria; NHRM, Naturhistoriska Riksmuseet, Stockholm, Sweden; NIBR, National Institute of Biological Resources; SNU, Seoul National University, Seoul, South Korea; USNM, United States Museum of Natural History, Washington D.C., USA; ZAUC, Institute of Applied Entomology, Zhejiang University, Hangzhou 310029, Zhejiang, China; ZMUC, Zoologiske Museum, Copenhagen, Denmark; GB, Gyeongsangbuk-do; POL, the distance between posterior ocelli; LOL, distance between anterior and posterior ocellus; OOL, minimal distance between posterior ocellus and inner orbit; OD, maximum diameter of posterior ocellus; cc, costal cell; mv, marginal vein; pm, postmarginal vein; st, stigmal vein.

    Systematic Accounts

    Key to Korean species of the genus Megastigmus

    • 1. Body mostly black; at least mesoscutum to propodeum almost black ······························································· 2

    • – Body mostly yellow to brown; at most lateral sides of mesoscutum and propodeum black ···························· 3

    • 2. Body entirely black ····································· M. borriesi

    • - At least pronotum yellow ··························· M. inamurae

    • 3. Head and mesosoma partially black (Fig. 1A); propodeum with various rugulose sculptures anteriorly, but two circularly reticulate sculptures on submedian area (Fig. 1F); ovipositor sheaths approximately as long as the length of body ·········································· M. aculeatus

    • - Head and mesosoma entirely brown (Fig. 2A); propodeum smooth (Fig. 2F); ovipositor sheaths distinctly shorter than body length ··················································· M. rigidae

    Superfamily Chalcidoidea Latreille, 1817 좀벌상과

    Megastigmidae Thomson, 1876 왕꼬리좀벌과

    Megastigmus Dalman, 1820 왕꼬리좀벌속

    Megastigmus aculeatus (Swederus, 1795) (Fig. 1A–H) 장 미왕꼬리좀벌 (신칭)

    Pteromalus aculeatusSwederus, 1795: 221. Lectotype ♀. Type depository: NHRM, not examined. Type locality: Sweden.

    Torymus (Megastigmus) collarisBoheman, 1834: 332. Syntypes ♀♂. Type depository: NHRM. Type locality: Sweden. Synonym with Pteromalus aculeatusSwederus, 1795 by Milliron, 1949: 289.

    Torymus punctumFörster, 1841: 31. Syntype ♀. Type depository: NHMV, not examined. Type locality: Germany. Synonym with Megastigmus collarisBoheman, 1834 by Morley, 1910: 9.

    Megastigmus vexillumRatzeburg, 1848: 182. Syntypes ♀ ♂. Type destroyed. Type locality: Germany. Synonym with Megastigmus collarisBoheman, 1834 by Morley, 1910: 9.

    Megastigmus transversusWalker, 1833. Syntypes ♀. Type depository: NHMV. Type locality: UK, England. Synonym with Pteromalus aculeatusSwederus, 1795 by Milliron, 1949: 289.

    Megastigmus flavusFörster, 1859: 109. Syntypes ♀♂. Type depository: NHMV. Type locality: Germany. Synonym with Megastigmus collarisBoheman, 1834 by Mayr, 1874: 137.

    Megastigmus cynorrhodiPerris, 1876: 222. Syntypes. Type depository: MNHN, not examined. Type locality: France. Synonym under Pteromalus aculeatusSwederus, 1795 by Milliron, 1949: 289.

    Diagnosis. Female (Fig. 1A). Length of body excluding ovipositor sheath = 2.42–2.58 mm (Length of ovipositor sheath = 2.40–2.58 mm). Body mostly brownish yellow to pale yellow with dark band as follows: around ocelli; postgena; lateral side of axilla to upper side of propodeum; wing vein pale brown except stigma brown; antenna and ovipositor sheath dark brown. Head 1.3× as wide as high in frontal view, 1.5× as wide as long in dorsal view; OOL: POL: LOL: OD = 1.5–1.6: 3.3–3.4: 1.4–1.5: 1.0. Face with two rows of setae on frons; with white setae on lower face. Propodeum with various rugulose sculptures anteriorly, but two circularly reticulate sculptures on submedian area. Fore wing with cc: mv: pm: st = 3.8–4.0: 2.0–2.2: 2.1–2.3: 1.0; stigma 1.9× as high as width.

    Male (Fig. 1B). Similar to female in morphology and coloration, but differs in having a larger stigma.

    Variation. Megastigmus aculeatus shows considerable intraspecific variation in body coloration throughout its wide geographic range and across different host associations. Females may vary from pale yellow to yellowish brown or light brown, and the extent, intensity, and sharpness of darker maculations on the head (especially around the ocelli), mesosoma, and metasoma differ markedly among individuals and populations. In some specimens, dark markings are well defined and strongly contrasting, whereas in others they are weakly developed, diffuse, or nearly absent. Similar variation has been observed in the degree of color contrast between dorsal and ventral surfaces of the metasoma (Roques and Skrzypczyńska, 2003).

    Material examined. 5♀1♂, Hado reservoir, Hado-ri, Namcheon- myeon, Gyeongsan-si, GB, Korea, 35°43'11.4"N 128° 44'31.6"E, fruits of R. multiflora collected 16.iv.2016, adults emerged 06.ii.2017. Duk-Young Park (1♀ in NIBR and 4♀1 ♂ in SNU).

    Distribution. Korea (new record), Argentina, Armenia, Australia, Austria, Bosnia Hercegovina, Bulgaria, Caucasus, China, Croatia, Czech Republic, Denmark, Ethiopia, Finland, France, Germany, Greece, Hungary, Iran, Iraq, Italy, Japan, Kazakhstan, Moldova, Montenegro, Morocco, Nearctic, Netherlands, New Zealand, Poland, Romania, Russia, Serbia, Slovakia, Somalia, South Africa, Spain, Sweden, Switzerland, Tadzhikistan, Turkmenistan, Ukraine, United Kingdom, United States of America.

    Host. Rosaceae:Rosa arvensis Huds, R. beggeriana Schrenk, R. blanda Aiton, R. canina L., R. corymbifera Borkh., R. gallica L., R. jundzillii Besser, R. majalis Herrm., R. multiflora Thunb. (first Korean record of the host association), R. palustris Marshall, R. pendulina L., R. pouzinii Tratt., R. rubiginosa L., R. rugosa Thunb., R. spinosissima L., R. turkestanica Regel, R. villosa L., R. virginiana Mill.

    Megastigmus borriesiCrosby, 1913 전나무왕꼬리좀벌 (신칭)

    Megastigmus borriesiCrosby, 1913: 169. Holotype ♀. Type depository: USNM. Type locality: Japan.

    Material examined. Not examined in this study.

    Distribution. Denmark, Finland, Japan, Korea, Russia.

    Host. Pinaceae.Abies koreana E.H. Wilson, A. mariesii Mast., A. sachalinensis F. Schmidt, A. sikokiana Lindley, A. veitchii Lindley.

    Remark.Roques and Skrzypczyńska (2003) previously recognized this species, with a single Korean female specimen collected in 1969 from A. veitchii and deposited in the USNM. However, the species was somehow missed out in the Check list of Insects from Korea (KSAE and ESK, 2021).

    Regarding the host plant from Korea, as Roques and Skrzypczyńska (2003) mentioned above, A. veitchii, in fact, is native to Japan according to WFO (2025) and it is not distributed in Korea. Therefore, the collector or identifier of the specimen collected in 1969 might have misidentified the host plant. Another possibility is that the host plant name above would have meant A. nephrolepis (Trautv. ex Maxim.) Maxim., which had been treated as A. veitchii var. nephrolepis in the past and is widely distributed from Russian Far East to Korean peninsula. Based on this information, the Korean host plant of M. borriesi is likely to be A. nephrolepis although the occurrence of the wasp from the plant is yet to be confirmed in the country.

    Megastigmus inamuraeYano, 1918 낙엽송꼬리좀벌

    Megastigmus inamuraeYano, 1918: 47. Syntypes. Type destroyed. Type locality: Japan

    Material examined. Not examined in this study.

    Distribution. Japan, Korea.

    Host. Pinaceae.Larix gmelinii (Rupr.) Göpp., Larix kaempferi (Lamb.) Carrière

    Remark. The species was first recorded from Korea by Paik (1974), and Paik (1978) subsequently noted its occurrence in North Korea. Its actual occurrence in the peninsula may need to be reevaluated due to absence of specimens.

    Megastigmus rigidaeXu & He, 1998 (Fig. 2A–F) 노간주왕 꼬리좀벌 (신칭)

    Megastigmus rigidaeXu & He, 1998 in Xu et al., 1998: 298 –299. Holotype ♀. Type depository: ZAUC. Type locality: China, Inner Mongolia.

    Redescription. Female (Fig. 2A). Length of body excluding ovipositor sheath = 3.30–3.36 mm (Length of ovipositor sheath = 1.8–1.9 mm). Body entirely yellowish brown to brown, with ventral area of metasoma distinctly dark brown. Antenna bicolored, with scape and pedicel yellowish brown and funicle dark brown. Ovipositor sheaths dark brown. Body surface moderately shiny, clothed with short, hair-like, erect setae distributed over head, mesosoma, and metasoma. Fore wing (Fig. 2B) hyaline and evenly covered with fine setae; venation pale brown; stigma distinctly darker brown than remaining veins.

    Head transverse. In frontal view (Fig. 2C), head 1.2× as high as wide; in dorsal view (Fig. 2D), head 1.5× as wide as long. Compound eyes large, oval, occupying most of lateral sides of head. Ocelli (Fig. 2D) arranged in a slightly obtuse triangle; OOL: POL: LOL: OD = 1.2–1.3: 2.6–2.7: 1.1: 1.0. Vertex and frons smooth to weakly coriaceous, bearing scattered erect dark setae. Frons (Fig. 2C) with three to four longitudinal rows of short dark setae; lower face distinctly clothed with longer, white setae. Antennal toruli situated below mid-height of compound eyes. Malar space moderately developed, approximately half the height of compound eye (Fig. 2C). Mandible 4-toothed; maxillary palpus 4-segmented; labial palpus 3- segmented.

    Antenna. Antenna filiform. Scape slender, gently curved, gradually widened apically, without conspicuous medial swelling; length approximately 3.8–4.0× as long as its maximum width. Pedicel short, 1.5× as long as wide, distinctly shorter than first funicular segment. Funicle apparently 6- segmented; gradually widening apically. Funicular segments cylindrical and clearly separated; F1–5 distinctly longer than wide, but F6 slightly shorter than preceding segments. All funicular segments with short, suberect setae. Clava 2.3× as long as wide; apically blunt, apparently composed of three fused segments but externally indistinctly segmented; slightly wider than funicle, gradually tapering apically.

    Mesosoma. In dorsal view (Fig. 2E), mesosoma distinctly longer than wide; pronotum 0.7× as long as wide. Pronotum, mesoscutum, metascutellum, and axillae with coarse transverse sculpture. Axillae (Fig. 2E) with fine longitudinal sculpture curved posteriorly, with only inner region nearly smooth or weakly longitudinally sculptured. Mid lobe of mesoscutum (Fig. 2E) bearing seven pairs of dark setae posterolaterally. Lateral lobe of mesoscutum (Fig. 2E) with four pairs of dark setae along inner line and seven pairs of dark setae along lateral margin. Scutellum (Fig. 2E) with four pairs of dark setae along lateral margin. Each axilla (Fig. 2E) with nine pairs of dark setae. Propodeum (Fig. 2F) smooth and shiny throughout, without median carina. Spiracles located laterally near anterior margin. Propodeal setation sparse, consisting of short, erect setae along lateral margins; median area largely asetose. Fore wing with cc: mv: pm: st = 4.2–4.3: 1.6–1.7: 1.6–1.7: 1.0; stigma 1.7× as high as width (Fig. 2B).

    Metasoma. Metasoma ovate, moderately elongate, slightly laterally compressed (Fig. 2A), smooth. Terga weakly convex, without conspicuous sculpture, bearing sparse, short, hair-like setae mainly along posterior margins of terga. Petiole short and transverse, slightly wider than long, smooth dorsally. Gaster gradually widening posteriorly from petiole to about middle, then gently tapering toward apex.

    Male. Unknown.

    Variation. The Korean specimens generally agree well with the original description of Megastigmus rigidaeXu & He, 1998 in major diagnostic characters, including host association and wing venation ratios. However, several differences were observed, such as smaller body size, darker body coloration, and weaker mesoscutal sculpture. These differences are considered to represent intraspecific or geographic variation rather than species-level divergence.

    Material examined. 3♀, Mt. Geumo, Namtong-dong, Gumisi, GB, Korea. 36°07'15.0"N 128°18'14.7"E, fruits of J. rigida collected 27.v.2018, adults emerged 03.vi.2018, Duk-Young Park (1♀ in NIBR and 2♀ in SNU).

    Distribution. Korea (new record), China.

    Host. Cupressaceae:Juniperus rigida Siebold & Zucc.

    Acknowledgements

    This work was supported by a grant from the National Institute of Biological Resources (NIBR), funded by the Ministry of Environment (MOE) of the Republic of Korea (NIBR2020 02205), by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. RS-2024- 004067 51), and by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea (NRF-RS-2025-00561722).

    Statements for Authorship Position & Contribution

    • Park, D.-Y.: Seoul National University, Ph.D. Student; Designed the research and wrote the manuscript

    • Lee, S.: Seoul National University, Professor; Revised the manuscript

    All authors read and approved the manuscript.

    Figure

    KJAE-65-1-65_F1.jpg

    Megastigmus aculeatus. A. female; B. male; C. frontal head; D. dorsal head; E. dorsal mesosoma; F. propodeum; G. stigma vein of female; H. stigma vein of male.

    KJAE-65-1-65_F2.jpg

    Megastigmus rigidae. A. female; B. stigma vein; C. frontal head; D. dorsal head; E. dorsal mesosoma; F. propodeum.

    Table

    Reference

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    Vol. 40 No. 4 (2022.12)

    Journal Abbreviation Korean J. Appl. Entomol.
    Frequency Quarterly
    Doi Prefix 10.5656/KSAE
    Year of Launching 1962
    Publisher Korean Society of Applied Entomology
    Indexed/Tracked/Covered By