Monoctenus nipponicus Takeuchi, 1940

Hara, Hideho & Nagase, Hirohiko, 2023, The Japanese species of Monoctenus (Hymenoptera: Diprionidae), Zootaxa 5380 (6), pp. 541-561 : 554-555

publication ID	https://doi.org/ 10.11646/zootaxa.5380.6.3
publication LSID	lsid:zoobank.org:pub:AA915DFA-58B9-428D-AF5D-193E3295AB04
DOI	https://doi.org/10.5281/zenodo.10371567
persistent identifier	https://treatment.plazi.org/id/03B38786-FF99-CD50-FF21-FAF8FC3956BE
treatment provided by	Plazi
scientific name	Monoctenus nipponicus Takeuchi, 1940
status

Treatment

( Figs 1B View FIGURE 1 , 2A View FIGURE 2 1, B1, C1, D1, 3B 2a, C2 View FIGURE 2 , 4A1, 8A1, B1, 9A1, 19)

Monoctenus nipponicus Takeuchi, 1940: 187 ; Gussakovskij 1947: 134, 136, 221; Takeuchi 1949: 50; Takeuchi 1955: 124; Togashi 1965: 252; Okutani 1967: 48; Smith 1975: 410; Okutani 1984: 24; Abe & Togashi 1989: 545; Togashi 2001: 41, 42; Naito et al. 2004: 16; Yoshida 2006: 36; Yoshida 2010: 29; Taeger et al. 2010: 211; Sundukov 2017a: 5; Sundukov 2017b: 35; Hara 2019: 46; Hara 2020: 287.

Additional description. Female. Length 5.5–6.0 mm. Coloration as in Takeuchi (1940) ( Fig. 19A, B View FIGURE 19 ), but labrum dark yellow to dark brown, palpi yellow, basally dark brown, pronotum often posterodorsally yellow to brown ( Fig. 3B View FIGURE 3 2a View FIGURE 2 ), coxae usually apically yellow narrowly, trochanters and trochantelli sometimes partly yellowish.

Clypeus with median furrow throughout or dorsally ( Fig. 19E View FIGURE 19 ) or without median furrow. Antenna with 19–20 antennomeres ( Figs 4A View FIGURE 4 1 View FIGURE 1 , 19F View FIGURE 19 ); flagellomere 6 in lateral view with breadth including serration 1.5–1.8 × dorsal length. Valvula 3 in dorsal view with same width throughout and apex slightly concave ( Figs 2C View FIGURE 2 1, 19G), in lateral view with apex nearly truncate ( Figs 2D View FIGURE 2 1, 19H); apical groove rather wide ( Fig. 19I View FIGURE 19 ). Lance in lateral view with dorsal edge concave near base, gently rounded from middle to apex ( Fig. 19J View FIGURE 19 ). Lancet with 10 annuli, acute apically ( Figs 3C View FIGURE 3 2 View FIGURE 2 , 19K, L); length from ventral end of ctenidium 1 to apex 3.4–3.6 × breadth; ctenidium 1 slightly converging with ctenidium 2; ctenidia 2–6 inclined anteriorly.

Male. Figs 8A View FIGURE 8 1 View FIGURE 1 , 19C, D View FIGURE 19 . Length 5.2–6.4 mm. Pronotum sometimes posterodorsally yellow brown. Antenna with 25–26 rami (28–29 antennomeres) ( Fig. 1B View FIGURE 1 ). Subgenital plate in ventral view truncate apically. Genitalia Fig. 17M View FIGURE 17 . Penis valve with paravalva nearly straight on ventral edge ( Figs 8B View FIGURE 8 1 View FIGURE 1 , 9A View FIGURE 9 1 View FIGURE 1 , 19N View FIGURE 19 ); inner sclerite widest near middle; valviceps 2.5–2.7 × as long as broad.

Larva. The trunk yellow green and the head pale brown according to Okutani (1984).

Material examined. Holotype ( Fig. 19A, B, E–K View FIGURE 19 ): ♀, labelled “15, IV, 1920 Katayama Takeuchi” and “ Monoctenus nipponicus Tak. Holotype ”. Paratypes: 1♂, same data label as holotype and “ Monoctenus nipponicus Tak. Allotype ” ( Figs 1B View FIGURE 1 , 19C, D View FIGURE 19 ) ; 1♀ 2♂, same data as holotype ( Fig. 8B View FIGURE 8 1 View FIGURE 1 , 9A View FIGURE 9 1 View FIGURE 1 ) ; 1♀, “15, IV, 1920 Gifu Takeuchi ” ; 1♀, “[Fuchu-mura](in Japanese) 1939.4.23. NAKANISHI” .

The males of M. nipponicus and M. kondoi are not distinguishable, so we inferred the species of males from females collected at the same site on the same day. We were unable to identify the three male paratypes of M. nipponicus (see Appendix).

Other material examined: JAPAN: HONSHU: 1♀, Nara Pref., Yamatokoriyama, Yata, 17. IV. 2013, F. Ito ( Figs 3C View FIGURE 3 2 View FIGURE 2 , 4A1); 1♀, Hyogo Pref., Tamba-Sasayama, Juniperus rigida , 27. III. 1966, T. Okutani (probably material of Okutani, 1967, 1984); 1♀, Hyogo Pref., Kobe, Kita Ward, Dojo, 18. IV. 2012, H. Yoshida ( Fig. 2A View FIGURE 2 1, B1); 1♀ 4♂, ditto but 8. IV. 2013 ( Figs 2C View FIGURE 2 1, D1, 3B 2a View FIGURE 2 , 8A1, 19M, N).

Distribution. Japan: Honshu ( Takeuchi 1940), Awaji Island ( Naito et al. 2004). Russia: Primorsky ( Sundukov 2017a).

Host plant. Cupressaceae : Juniperus rigida Siebold et Zucc. ( Takeuchi 1940, Okutani 1967).

Life history. The adults appear from March to May ( Takeuchi 1955, Hara 2020). The male adults actively fly over the host plant ( Okutani 1984).

Remarks. Monostenus nipponicus ( Fig. 19A, B View FIGURE 19 ) has the same color as M. obscuratus hokkaidonis ( Fig. 20A– B View FIGURE 20 ) and the pale specimens of M. obscuratus obscuratus (Hartig, 1937) (fig. 226 in Borowski & Stawski 2021). Monoctenus obscuratus obscuratus usually has a mostly blackish brown hind tibia and distinctly infuscated wings (images of the female and male syntypes in Taeger et al. 2018), but the pale specimens, just like M. nipponicus , have an entirely yellow hind tibia and slightly infuscated wings. Monoctenus nipponicus is distinguished from M. obscuratus by having a female antenna with 19–20 antennomeres ( Figs 4A View FIGURE 4 1 View FIGURE 1 , 19F View FIGURE 19 ), a flagellomere 6 with the breadth including the serration 1.5–1.8 × the dorsal length ( Figs 4A View FIGURE 4 1 View FIGURE 1 , 19F View FIGURE 19 ), a male antenna with 26–27 rami and a valviceps 2.5–2.7 × as long as broad in the lateral view ( Figs 8B View FIGURE 8 1 View FIGURE 1 , 9A View FIGURE 9 1 View FIGURE 1 , 19N View FIGURE 19 ). The two subspecies of M. obscuratus has a female antenna with 18 antennomeres ( Figs 4A View FIGURE 4 2 View FIGURE 2 , 20E; images 12885, 18571 in Taeger et al. 2018), a flagellomere 6 with the breadth including the serration 1.1–1.4 × the dorsal length ( Figs 4A View FIGURE 4 2 View FIGURE 2 , 20E; images 3642 (syntype), 12885 in Taeger et al. 2018), a male antenna with 22–24 rami ( Enslin 1917, Gussakovskij 1947, Viitasaari & Varama 1987, Mol & Aarsten 1994, our material) and a valviceps 2.9–3.5 × as long as broad ( Figs 9A View FIGURE 9 2 View FIGURE 2 , 20O; fig. 12b in Viitasaari & Varama 1987, fig. 4 in Mol & Aarsten 1994).

Monostenus nipponicus is also similar to M. juniperi (Linné, 1758) from Europe. They are separated as follows: M. nipponicus has a female abdomen almost entirely black ( Fig. 19A, B View FIGURE 19 ), a female antenna with 19–20 antennomeres, a flagellomere 6 with the breadth including the serration 1.5–1.8 × the dorsal length ( Figs 4A View FIGURE 4 1 View FIGURE 1 , 19F View FIGURE 19 ) and a male antenna with 26–27 rami, but M. juniperi has a female abdomen laterally yellow (images in Taeger et al. 2018), a female antenna with 16–18 antennomeres, a flagellomere 6 with the breadth including the serration 1.1–1.2 × the dorsal length ( Fig. 18A View FIGURE 18 ) and a male antenna with 17–21 rami ( Gussakovskij 1947, Viitasaari & Varama 1987, Zhelokhovtsev & Zinovjev 1988, Mol & Aarsten 1994, our material). Their ovipositors slightly differ: M. nipponicus has a lance with the dorsal edge slightly concave basally ( Fig. 19J View FIGURE 19 ) and the length of a lancet from the ventral end of the ctenidium 1 to the apex 3.4–3.6 × the breadth and the ctenidia 1 and 2 of a lancet very slightly converging dorsally ( Fig. 19K, L View FIGURE 19 ), but M. juniperi has a lance with the dorsal edge not concave basally ( Fig. 18B View FIGURE 18 ) and the length of a lancet from the ventral end of the ctenidium 1 to the apex 4.3–4.5 × the breadth and the ctenidia 1 and 2 distinctly converging dorsally ( Fig. 18C, D View FIGURE 18 ). Takeuchi (1940) used the presence or absence of a median clypeal furrow to separate these two species (present in M. nipponicus but absent in M. juniperi according to him), but in our material, a median clypeal furrow is present or absent in M. nipponicus and absent in M. juniperi . This character is not very useful to distinguish them.

Monoctenus nipponicus is also similar to M. kondoi from Japan. Their females differs as mentioned in the key and the remarks of the latter. Their males are indistinguishable.

This species is separated from other species of Monoctenus by the coloration (compare with the descriptions of other species of the genus by Norton 1872, Cresson 1880, Marlatt 1888, Gussakovskij 1947, Smith 1975, Smith et al. 2010, De Lira-Ramos et al. 2022, Japoshvili & Haris 2022, this study).