Head in dorsal view hexagonal, tapered behind eyes, without projections or depressions (Figs 1F, 4F); antennal shelf prominent; eye small; setae of temple straight and directed downwards; occiput with a dense golden cushion of setae; female flagellum 10-segmented with 4- or 5-segmented expanded clava; F10 slightly narrower than F9; male flagellum 12-segmented, without long whorled setae, F2 modified. Pronotal collar with a narrow, dense, golden, cushion of setae (Figs 1C, 4B); notauli absent; scutellum with anterior scutellar pit; scutellar disc tectiform, with a sharp medial keel or flat to weakly raised, with short, blunt keel (Figs 1C, 4B, D). Fore wing without basal vein. Propodeum slightly concave posteromedially, without specialized flanges at sides. Tarsi cylindrical, with tarsomeres about as high as wide. Petiole in lateral view slightly raised, not elevated above level of anterior margin of T2; anterior margin of T2 entire, wider than width of petiole.

Figure 1. 

Tetramopria tortilis male from South Korea (H) and female (A–G) from Japan: A lateral habitus B mesosoma, lateral view C mesosoma, dorsal view D mesosoma, ventral view E antenna, lateral view F head, dorsal view G mesosoma, latero-ventral view H mid leg; white arrows postpectal carina. Scale bars: 1.0 mm (A); 0.5 mm (B, C, E); 0.3 mm (D); 0.2 mm(F, G).

We have followed the interpretation of Tetramopria used by Notton (1994). This concept is very similar to that of Sundholm (1960) who provided a key to separate Tetramopria from Diapria Latreille, 1796, Trichopria Ashmead, 1893 and Viennopria Jansson, 1953, and the concept of Huggert and Masner (1983) who keyed Tetramopria from additional Holarctic genera of myrmecophile Diapriini not covered by Sundholm (1960).

Based on the original description, Tetramopria castanea (Kieffer, 1911) satisfies the definition of the aurocincta group of Notton (1994); scutellar disc tectiform with a sharp medial keel; female antennal clava four-segmented. Therefore, although the states of the anterior scutellar pit and T2 are unknown, T. castanea is included in the aurocincta group.

(2♂♂6♀♀) Japan • 1♀; Ibaraki Pref., Ishioka, Ishikawa; 11 IV 2024; Y. Komatsuzaki leg.; (ELKU) • 1♂1♀; Nagano Pref., Matsumoto, Jôyama; 5 IV 2010; T. Komatsu leg.; from nest of Tetramorium tsushimae; (ELKU) • 1♀; Shizuoka Pref., Iwata, River Ohta, YPT, 16 VI 2001, M. Urai leg. (NBC) • 1♀, Aichi Pref., Kasugai, Takagi, deciduous forest; EmT; 15–21 VI 1994; K. Sanda leg.; (NBC). South Korea • 2♀♀; Ulsan Metropolitan City, Ulju-gun, Cheongnyang-eup, Munjuk-ri; 24 VI 2024; Seonwoo Yoon leg.; from nest of Tetramorium tsushimae; (ELKU) • 1♂; Ulsan Metropolitan City, Ulju-gun, Cheongnyang-eup; Munjuk-ri; 1 VII 2024; Seonwoo Yoon leg.; from nest of Tetramorium tsushimae; (ELKU).

Female flagellum 10-segmented with 5-segmented gradually expanded clava; male F1 about 4.0 times as long as its greatest width. Propleuron smooth and shiny, with a small area of pubescence latero-ventrally (Fig. 1G). Anterior scutellar pit strongly costate (Fig. 1C); scutellar disc weakly raised, with a short, blunt keel medially (Fig. 1C). Mesopleuron with postpectal carina ventrally (Fig. 1D, white arrow) and broad mesocoxal depression, forming a pronounced ventral concavity in front of mid coxae in lateral view (Fig. 1B). Male with mid-trochanter expanded, triangular, with mid-tibia strongly twisted. T2 without subbasal foveae.

Body length 1.8–2.3 mm.

Japan (Honshu: Ibaraki, Nagano, Shizuoka, Aichi; Kyushu?) (Notton 1994; Maruyama et al. 2013; Kawai et al. 2024). South Korea, new record. In Maruyama et al. (2013), Kyushu was also listed as a locality. However, this record was not based on specimens, but rather on observations by Dr. T. Komatsu (Dr. Maruyama per. comm.). As we were unable to confirm any specimens from Kyushu, this record needs confirmation.

Tetramopria tortilis has been collected from the nests of Tetramorium tsushimae Emery, 1925 both in Japan and Korea. In Ibaraki Prefecture (Japan) Tetramopria tortilis was collected from a nest of Pristomyrmex punctatus (Smith, 1860), but based on the ecological characteristics of other species of the genus Tetramopria and the circumstances of the collection site, Kawai et al. (2024) considered these wasps were considered to have been associated with Tetramorium tsushimae. Specimens of Tetramopria sp. collected from Tetramorium tsushimae nests reported by Maruyama et al. (2013) were re-examined by RK and are also T. tortilis. Unfortunately, there are some errors in the collection dates and number of male and female specimens collected by Dr. T. Komatsu mentioned Maruyama et al. (2013), and we have provided the correct data above. So, Maruyama et al. (2013) was the first report of the biology of this species from Japan. During the current study SY collected adults of T. tortilis from nests of Tetramorium tsushimae during 2024, at Ulsan city (South Korea). The parasitoid host of T. tortilis is unknown but is probably a dipteran.

Courtship and copulation was observed by SY as follows: the male mounts the female with the two individuals facing the same way; the male grips the base of the females wings using the tibiae and tarsi of his mid leg and extends his forelegs laterally and hind legs posteriorly (Fig. 2A); the female may prevent further courtship by walking off in which case her antennae are held forward where they cannot be antennated (See Suppl. material 1); if the female is receptive, she will stand still and raise her antennae so that the male can antennate them (like Fig. 2A); the male strokes the female antenna alternately with each of his antennae bringing the RSS on his F2 into contact with the female antenna; if the male is not acceptable, she may try to push him away with her hind legs while the male uses his front and middle legs to grasp and hold the female’s mesosoma (Fig. 2B); if the female accepts the male, the male moves backwards, and copulation follows; probably the female signals her acceptance by bending both antennae backwards; the male inserts his genitalia into the female genital pore while grasping the female’s metasoma with the fore and middle legs; during copulation the male’s hind legs remain in contact with the substrate (Fig. 2C). Various interactions with host ants were observed by SY as follows: mouth to mouth contact between male or female wasp and worker ant (Fig. 2D, E); antenna and petiole biting of female wasp and carrying female wasp by ants (Figs 2F, 3A); pronotum licking of male wasp by ants (Fig. 3D); petiole licking of ants by female wasp (Fig. 3B); and licking of ant heads by male wasp were observed (Fig. 3C).

Figure 2. 

Courtship of Tetramopria tortilis (A–C) and interaction of T. tortilis and Tetramorium tsushimae (D–F): A male wasp mounted on a female holding the female’s wings with his mid legs and with his forelegs extended laterally and hind legs posteriorly B female wasp trying to push the male off with her hind legs C male wasp grasping female metasoma with his fore and middle legs, and with his hind legs remaining on the substrate D mouth to mouth contact between male wasp and worker ant E mouth to mouth contact between female wasp and worker ant F worker ant biting antenna of female wasp and carrying female wasp.

Figure 3. 

Interaction of T. tortilis and Tetramorium tsushimae (A–D): A worker ant biting petiole of female wasp B female wasp licking petiole of worker ant C male wasp licking head of worker ant D worker ant licking pronotum of male wasp.

(1♂4♀♀) Japan • 1♂; Aichi Pref., Nisshin, Komenogi; MT; 25 VI–1 VII 2011; H. Seo leg.; (NBC) • 1♀; Mie Pref., Yokkaichi, Komatsu; YPT; 18–25 VI 1996; S. Hanaoka leg.; (NBC). South Korea • 3♀♀; Ulsan Metropolitan City, Ulju-gun, Cheongnyang-eup, Munjuk-ri; 24 VI 2024; Seonwoo Yoon leg.; from nest of Tetramorium tsushimae; (ELKU).

Frons more convex than for T. aurocincta; female flagellum 10-segmented with 4-segmented gradually expanded clava; male F1 about 2.5 times as long as its greatest width. Propleuron smooth, with sparse short setae latero-ventrally (Fig. 4G). Anterior scutellar pit more or less costate (Fig. 4B, D); scutellar disc tectiform, with a sharp medial keel covering its entire length and extending forwards into anterior scutellar pit (Fig. 4B); scutellar disc emarginate posteriorly. Mesopleuron with scattered hairs in lower half, without pronounced ventral concavity in front of mid coxae. Male mid-trochanter and mid-tibia unmodified. Dorsal part of propodeum deeply foveate posteriorly (Fig. 4D, white arrow). T2 with two shallow subbasal foveae, very finely striate inside (Fig. 4D, green arrow).

Figure 4. 

Tetramopria turbinata male from Japan (H), female from South Korea (A–G) and Trichopria drosophilae male from Japan (I): A lateral habitus B mesosoma, dorsal view C tip of metasoma, dorsal view D propodeum, petiole and anterior part of T2, dorsal view E antenna, lateral view F head, dorsal view G mesosoma, latero-ventral view H trochanter, femur, tibia and basitarsus of mid leg I mid leg; white arrow fovea of propodeum; green arrow fovea of anterior part of T2. Scale bars: 1.0 mm (A); 0.5 mm (B, E); 0.3 mm (D); 0.2 mm (C, F, G).

Female. Body length except ovipositor 2.3–2.8 mm. Body black and dark brown, except mandibles, antennae, tegulae and legs brown, scape and antennal club darker. Occipital, metapleural and pronotal pubescence golden, petiolar pubescence white.

Head. Head with short, semidecumbent to adpressed setae. Head in dorsal view as long as wide, hexagonal, tapered behind eyes. Head in lateral view slightly longer than high (17: 15), face slightly convex. Occiput with a dense cushion of setae. OOL: POL: LOL = 11: 5: 3. Eye small, its maximum width slightly longer than malar space (23: 21). Pleurostomal distance 0.6 times as long as maximum width of head. Basal margin of mandible costate. Mandible apically bidentate, only overlapping a little. Upper tooth of mandible shorter than lower tooth. Antenna with setae on all segments. Scape compressed, slightly curved, with reticulate-coriaceous sculpture (Fig. 4F). Pedicel longer than wide (16: 11). F1–F6 gradually widened towards apex. Flagellum with 4-segmented antennal club, its ventral part with dense sensilla. F10 conical. Ratios of length to maximum width of each flagellomeres in lateral view: F1 19: 10; F2 15: 10; F3 13: 10; F4 12: 11; F5 12: 13; F6 12: 14; F7 16: 18; F8 19: 20; F9 19: 20; F10 22: 16.

Mesosoma. Mesosoma slightly wider than head (39: 35). Pronotal collar wide, vertical, with a dense cushion of setae, interrupted at top of pronotum (Fig. 4B). Pronotal shoulder rounded. Lateral part of pronotum smooth and shiny. Propleuron smooth, with sparsely short setae latero-ventrally (Fig. 4G). Mesoscutum smooth, convex anteriorly, flat posteriorly with 5–10 short semidecumbent setae. Anterior scutellar pit transverse, curved, costate, divided into small foveae (Fig. 4B, D). Scutellar disc weakly convex, sulcate laterally and posteriorly. Medial keel of scutellar disc covering its entire length and extending forwards into anterior scutellar pit. Mesopleuron smooth, without median oblique impression and few scattered setae. Mesopleuron in lateral view convex posteroventrally, in front of mid coxal insertion, not concave like T. tortilis. Metascutellum with strong median keel and lower lateral keel. Metapleuron with short, adpressed setae laterally, and long setae dorsally (Fig. 4A). Lateral part of propodeum with short, adpressed setae anteriorly, with a band of long setae behind that, and the posterior margin of the propodeum bare. Dorsal area of propodeum with adpressed setae. Medial keel of propodeum simple, strongly developed, raised anteriorly. Propodeum with lateral keel developed, posteriorly produced as a tooth. Posterior margin of propodeum concave. Basal part of all femora compressed and reticulate-coriaceous. Apical part of all femora enlarged and smooth. Basal part of mid and hind tarsi laterally compressed, smooth and shiny.

Metasoma. Petiole in lateral view slightly raised, dorsally visible part 1.1 times as long as its maximum width, covered with short adpressed setae anteriorly and longer setae posteriorly. Metasoma in dorsal view about 1.8 times as long as its maximum width, wider than mesosoma (95: 78). Postpetiole comprising six smooth, clearly differentiated tergites. T2–T5 with micropunctation medially (Fig. 4C). Anterior margin of T2 slightly concave with two shallow foveae, very finely striate inside. T3 and T4 with a pair of setae, T5 with three pair of setae, T6 with a pair of spiracles. T7 with pygostyles surrounded by several setae. Postpetiole comprising five smooth, shiny, clearly differentiated sternites. Anterior margin of S2 with two deep foveae covered with long setae. S3–S6 covered with micropunctation medially. Posterior part of S6 with several setae. Ovipositor sometimes slightly exposed.

Japan (Honshu: Aichi, Mie), new record; South Korea (Notton 1994).

Tetramopria turbinata has been collected from the nests of Tetramorium tsushimae in South Korea by SW. In Japan, associated ants are unknown. The parasitoid host of T. turbinata is unknown but is probably a dipteran.

Courtship was observed by SY as follows: the male mounts the female with the two individuals facing the same way; the male grips the base of the females wings using the tibiae and tarsi of his mid leg (Fig. 5A), grips the female face or scapes with his fore tarsi (Fig. 5A, B), and extends his hind legs posteriorly or places them on the female metasoma; if the female is receptive, she will stand still and raise her antennae a little so that the male can antennate them; the male strokes the female antennae alternately with each of his antennae bringing the RSS on his F2 into contact with the female antenna (Fig. 5C). Successful courtship and copulation was not observed. Various interactions with ants were observed by SY as follows; mouth to mouth contact between female parasitoid and worker (Fig. 5F), biting of the base of the fore wing of male or female parasitoid by ants (Fig. 5D, E).

Figure 5. 

Courtship of Tetramopria turbinata (A–C) and interaction of T. turbinata and Tetramorium tsushimae (D–F): A, B mounting – male wasp holding the female’s wings with his mid legs C antennation – male wasp with his F2 in contact with the female antennal clava, also the male wasp is holding the female’s scapes with his front tarsi D worker ant biting base of fore wing of a male wasp E worker ant biting base of fore wing of a female wasp F mouth to mouth contact between a female wasp and a worker ant.