Tremex fuscicornis ( Fabricius, 1787 )

Shinohara, Akihiko, 2023, The woodwasp genus Tremex (Hymenoptera, Siricidae) of Japan, Zootaxa 5239 (1), pp. 1-40 : 24-26

publication ID	https://doi.org/ 10.11646/zootaxa.5239.1.1
publication LSID	lsid:zoobank.org:pub:E446D1F2-B922-45A9-9F6D-01406154594E
DOI	https://doi.org/10.5281/zenodo.7644316
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scientific name	Tremex fuscicornis ( Fabricius, 1787 )
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Tremex fuscicornis ( Fabricius, 1787)

( Figs 2B, F View FIGURE 2 , 3E–G View FIGURE 3 , 4C, D View FIGURE 4 , 5D, K View FIGURE 5 , 6C View FIGURE 6 , 7I, J View FIGURE 7 , 9C View FIGURE 9 , 10E–G View FIGURE 10 , 11D View FIGURE 11 , 12D View FIGURE 12 , 14 View FIGURE 14 ; Tables 1–4 View TABLE 1 View TABLE 2 View TABLE 3 View TABLE 4 )

Sirex fuscicornis Fabricius, 1787: 257 .

Tremex fuscicornis: Yano, 1932: 473 ; Gussakovskij, 1935: 67; Takeuchi, 1938: 193; Kono & Sugihara, 1939: 109; Benson, 1943: 30; Maa, 1949: 146; Takeuchi, 1949: 47; Takeuchi, 1950: 1333; Takeuchi, 1955a: 3, 7; Takeuchi, 1955b: 115; Takeuchi, 1962: 4, 10; Kim, 1963: 295; Okutani, 1965: 463; Okutani 1967: 44; Okutani, 1971: 18; Tanaka, 1971: 202; Okutani, 1973: 14; Togashi, 1973: 103; Okutani, 1977: 286; Smith, 1978: 96; Tanaka, 1979: 459; Murota & Kurokawa, 1985: 246;? Miyoshi, 1988: 187 (see comments below); Abe & Togashi, 1989: 558; Xiao et al., 1992: 58; Sakamoto, 1997: 24; Haneda et al., 1998: 324; Lee et al., 1998: 298 (in part); Naito et al., 2004: 68; Palma et al., 2005; 57; Taeger et al., 2016: 470; Yoshida, 2006: 105; Pažoutovaì & Šrůtka, 2007: 83; Taeger et al., 2010: 107; Schiff et al., 2012: 239; Sundukov & Lelej, 2012: 113; Sundukov, 2015: 251; Sundukov, 2017: 113; Nagase & Watanabe, 2018: 950; Lee et al., 2019: 14; Naito, 2019: 20; Naito, 2020: 467; Shinohara et al., 2020: 384.

Tremex longicollis: Nakamura & Fujishita, 1974: 103 . Not Fabricius, 1787 (see Sakamoto, 1997).

Tremex apicalis: Lee et al., 1998: 298 (in part). Not Matsumura, 1912.

See Smith (1978) and Lee et al. (2019) for more synonyms and references.

Diagnostic characters. Female. Length without ovipositor 17–34 mm. Head pale brown, usually with blackish areas around ocellar area, vertex, inner and outer orbits and posterior surface; head sometimes black with only temple pale brown. Antenna pale brown ( Fig. 5D View FIGURE 5 ), often partly darkened. Thorax black, pronotum largely pale brown to dark brown dorsally (often with irregular blackish marks, sometimes almost entirely black); parascutal lobe pale brown; mesonotum and mesoscutellum rarely marked with pale brown. Fore and mid legs with coxae, trochanters, and base and anterior surfaces of femora (sometimes almost entirely) black, tibiae and tarsi brown with basal halves of tibiae creamy white. Hind leg black, with tibia and tarsus brown, basal halves of tibia and tarsomere 1 creamy white. Forewing pale brownish hyaline, without distinct infuscation ( Fig. 7I, J View FIGURE 7 ). Abdomen black, with following pale brown: often anterior part of tergum 1, most of tergum 2, usually broad anterior margins of terga 3 and 7, narrow anterior margins of 4–6 (tergum 3 often almost entirely), anterior 1/2 of tergum 8 (except narrow anterolateral corner) and often marks of various sizes enclosed in posterior black part, posterior 1/2 and ventral part of tergum 9 (except for black area along posterior lateral margin), including most or entire precornal basin, and cornus. Antenna with 13 or 14 antennomeres. Pronotum ( Fig. 3E–G View FIGURE 3 ) short, MPL 0.40–0.60 (average 0.52) times as long as OOCL. Hind tibia 1.08–1.24 (average 1.14) times as long as hind tarsomere 1; dorsal margin of hind tibia straight or very shallowly concave ( Fig. 6C View FIGURE 6 ). Forewing 1.09–1.41 (average 1.23) times as long as ovipositor sheath. Abdominal tergum 8 0.84–1.30 (average 1.04) times as long as terga 5–7 combined; precornal basin short, its length 0.52–0.72 (average 0.63) times as long as wide, widest in posterior part ( Fig. 2B View FIGURE 2 ); ovipositor sheath 2.17–2.54 (average 2.34) times as long as apical sheath.

Male. Length 15–21 mm. Black. Fore and mid tibiae and tarsi mostly brown to dark brown. Wings brownish hyaline, veins dark brownish ( Fig. 9C View FIGURE 9 ). Temple densely punctate. Antenna with 12 or 13 antennomeres. Pronotum ( Fig. 4C View FIGURE 4 ) short, MPL 0.52–0.67 (average 0.61) times as long as OOCL. Hind tibia short, 1.26–1.35 (average 1.32) times as long as hind tarsomere 1.

Material examined. 70♀ 17³ (1♀ from Germany, 6♀ from China, 16♀ 2³ from Korea, 8♀ 15³ from Hokkaido and 39♀ from Honshu). See Appendix for collection data.

Distribution ( Fig. 14 View FIGURE 14 ). Japan (Hokkaido, Kunashiri Island, Honshu), Korea, China (almost all areas except for western and southern provinces ( Xiao et al. 1992)), Russia (Sakhalin, Siberia ( Sundukov 2017)), Europe (almost all areas except for Iberian Peninsula and UK ( Taeger et al. 2006)), introduced into Chile ( Schiff et al. 2012).

Host plants. Betulaceae : Alnus japonica (Thunb.) Steud. f. arguta (Regel) H.Ohba ( Kono & Sugihara 1939), Carpinus betulus ( Smith 1978) , Betula ermanii Cham. (Shinohara et al. 2020), Betula sp. ( Smith 1978) . Cannabaceae : Celtis sinensis Pers. ( Smith 1978) . Fagaceae : Quercus crispula Blume var. crispula ( Nakamura & Fujishita 1974; Sakamoto 1997), Quercus sp. , Fagus sylvatica L. ( Smith 1978). Juglandaceae : Pterocarya stenoptera C.DC. ( Maa 1949) ; Juglans regia L. ( Smith 1978). Leguminosae: Robinia pseudoacacia L. ( Maa 1949). Rosaceae : Cerasus x yedoensis (Matsum.) Masam. et S.Suzuki ( Okutani 1967). Salicaceae : Salix sp. , Populus tremula L., Populus nigra L., Populus pyramidalis , Populus italica , Populus sp. ( Smith 1978) . Sapindaceae : Acer negundo L., Acer platanoides L. ( Smith 1978). Ulmaceae : Ulmus davidiana Planch. var. japonica (Rehder) Nakai ( Kono & Sugihara 1939), Zelkova serrata (Thunb.) Makino ( Okutani 1967) .

Remarks. This is a widely spread Palaearctic species, also accidentally introduced in Chile ( Schiff et al. 2012). It is rather variable in coloration but may be characterized by the short pronotum ( Fig. 3E–G View FIGURE 3 ), the pale brownish hyaline forewing without distinct infuscation ( Fig. 7I, J View FIGURE 7 ), the abdomen with pale brown bands ( Fig. 10E–G View FIGURE 10 ) and the precornal basin widest in its posterior part ( Fig. 2F View FIGURE 2 ) in the female and the densely punctate temple ( Fig. 4D View FIGURE 4 ), the mostly brown to dark brown fore and mid tibiae and tarsi, the pale brownish hyaline forewing without distinct infuscation ( Fig. 9C View FIGURE 9 ) and the entirely black abdomen ( Fig. 12D View FIGURE 12 ) in the male.

The previously published collection data of this species in Japan are rather few. As far as I know, Yano (1932) was the first to record this species from Japan and Korea, though he did not give any collection data from the two countries. Takeuchi (1938) recorded this species from Honshu but only referring to Yano (1932). Takeuchi (1955a, b, 1962) recorded this species from Hokkaido and Honshu, but Takeuchi (1955b, 1962) gave collection records only from Kyoto, Honshu, none from Hokkaido. Thereafter, collection data have been published from various parts of Honshu by Tanaka (1971, 1979), Okutani (1973, 1977), Nakamura & Fujishita (1974, see Sakamoto 1997), Murota & Kurokawa (1985), Miyoshi (1988), Haneda et al. (1998), Naito et al. (2004) and Nagase & Watanabe (2018), from Hokkaido by Shinohara et al. (2020), from Kunashiri Island by Sundukov (2015) and from Korea by Togashi (1973) and Lee et al. (1998), but some of them gave only locality data.

Miyoshi (1988) included this species in the insect fauna of Yamaguchi prefecture, just noting “5 gatsu [=May], Iwakuni-shi”. This is a doubtful record because T. fuscicornis is known to occur in late summer to autumn ( Table 4 View TABLE 4 ), probably never in May. For the same reason, the collection record of one of the three specimens of this species cited by Naito et al. (2004) (“Nishinomiya-shi, 1ex., 1970. V. 6, K. Sakaguchi (KU)” in p. 68) needs confirmation. This specimen should have been deposited in KU or Kobe University, whose sawfly collection was all transferred to NSMT in 2017. However, I was not able to locate the specimen in the former KU collection now in NSMT. Togashi (1973) gave a collection data of this species in Korea (1♀, Seoul, 1. X. 1942). A male specimen recorded by Lee et al. (1998) as T. apicalis from Suweon, Korea, actually belongs to T. fuscicornis (see Appendix below).

I have examined specimens from Hokkaido and several prefectures including Aomori, Tochigi, Saitama, Mie and Osaka prefectures and Tokyo metropolis in Honshu (see Appendix for collection data) ( Fig. 14 View FIGURE 14 ). This is the first distribution record of T. fuscicornis from the five prefectures listed above and Tokyo.