Linycus exhortator exhortator (Fabricius, 1787)

Kikuchi, Namiki & Konishi, Kazuhiko, 2021, A taxonomic revision of the genus Linycus Cameron, 1903 from Japan, Zootaxa 4948 (4), pp. 546-558 : 549-552

Linycus exhortator exhortator (Fabricius, 1787)

( Figs 1-A–C , 2 , 3-H , 4-A , 5 )

Ichneumon exhortator Fabricius, 1787: 264 .

Ophion exhortator: Fabricius, 1793: 154 .

Hoplismenus dimidiatus Gravenhorst, 1829: 421 , syn. by Heinrich, 1962: 780.

Platylabus latior Pic, 1902: 58 , syn. by Hilpert et al. 1993: 185.

Platylabus tricolor Berthoumieu, 1904: 14 , syn. by Diller & Horstmann, 1997: 65.

Platylabus exhortator: Roman, 1912: 153 .

Platylabus exhortator var. meridionalis Seyrig, 1927: 205 , syn. by Selfa, 1995: 437.

Platylabus balearicus Hedwig, 1939: 15–16 , syn. by Riedel, 2008: 159.

Ectopius exhortator: Uchida, 1956: 73 .

Linycus exhortator: Perkins, 1959: 67 ; Tereshkin, 2009: 1455–1457.

Linycus exhortator exhortator: Heinrich, 1962: 780 ; Townes, Momoi & Townes, 1965: 514.

Specimens examined. JAPAN: [Hokkaidô] 43°06’21 N, 144°52’31 E, Bekanbeushi marsh, Akkeshi Town , 2♀ 6♂ (12–31. VII. 2003) , 2♂ (1–31. VIII. 2003) , MT, R. Matsumoto ( OMNH); 1♂ , 43°06’18 N, 144°53’51 E, Bekan- beushi marsh, Akkeshi Town , 2. VIII. 2003, R. Matsumoto ( OMNH); 1♂ , 43°05’49 N, 144°51’41 E, Bekanbeushi marsh, Akkeshi Town , 12. VII. 2003, R. Matsumoto ( OMNH); 1♀ 1♂ [ Fig. 1-C ], 43°04’07 N, 144°54’14 E, Bekan- beushi marsh, Akkeshi Town , 1–31. VIII. 2003, MT, R. Matsumoto ( OMNH); 1♀ , 44.461 N, 142.368 E, Mina- mibifuka Station, Bifuka Town , 11. VIII. 2017, M. Shizuki ( SEHU); 1♀ , Kyushu Univ. Exp. Forest, Ashoro Town , 24–26. VI. 1980, K. Maetô ( NIAES); 1♀ , Masike , 24. VII. 1964, K. Kusigemati ( SEHU) ; 43°00’ N, 141°24’ E, Hitsujigaoka, Sapporo City , 2♂ (23–30. VII. 2003, MT [ Fig. 2-H ]) , 1♂ (23–30. VI. 2008, MT) , 1♂ (7–14. VII. 2008, MT) , 1♀ (22–29. VI. 2010, MT) , 1♂ (13–14. VIII. 2010, MT) , 1♂ (18–25. VII. 2011, MT) , 1♀ (3–6. VIII. 2011, YPT in potato field), 1♀ (17–18. VIII. 2011, YPT in potato field), 1♂ (8. X. 2011 [ Fig. 5 ]), 1♂ (1. XI. 2011), 1♀ (19–20. VII. 2012, YPT in potato field), 1♀ (31. VII. – 1. VIII. 2012, YPT in lettuce field [ NKHU0042 , Figs 1-A , 2-A–G , 3-H , 4-A ]) , K. Konishi ( EUMJ); 1♀ , Maruyama, Sapporo City, 12. VI. 1980, K. Maetô ( NIAES); Sapporo , 1♀ (25. VI. 1965) , 1♀ (8. IX. 1967) , K. Kusigemati ( SEHU); 1♂ , Hokkaido Univ. Exp. Forest, Toma- komai City, 18–20. VI. 1980, H. Takemoto ( NIAES); Touya , 3♂ (7. VII. 1967) , 1♂ (9. VII. 1967) , K. Kusigemati ( SEHU); 6♂ , 42.7794 N, 141.5863 E, Mamachi-gawa, Izumisawa, Chitose City , 12–27. VII. 2014, MT, N. Kuhara ( EUMJ). [Honshû] Aomori Pref.: Towada , 1♂ (24. VIII. 1966) , 1♀ (25. VIII. 1966) , K. Kusigemati ( SEHU); 1♂ , Sakaimatsu, Aomori City, 13. IX. 1993, T. Ichita ( SEHU). Iwate Pref.: Mt. Hayachine , 2♀ (27. VI. – 5. VII. 1989) , 3♂ (19–25. VII. 1989), MT, M. Sharkey and H. Makihara ( NIAES). Ibaraki Pref.: 1♂ , Narui, Tôyama, Ushiku City , 27. IV. 2009, H. Yoshitake and T. Kurihara ( EUMJ). Toyama Pref.: 1♂ , Kamimomose, Togamura, Nanto City , 28. VII. – 4. VIII. 2009, MT, M. Watanabe ( KPMNH [KPM-NK 55267]). Hyôgo Pref.: 1♀ , Sasayama , 29. VII. 1962 ( MHNAH). [Shikoku] Ehime Pref.: 1♂ , Ishitegawa Dam, Matsuyama, 16. VI. 1977, N. Takaki ( EUMJ). Tokushima Pref.: Ôkawara , Sanagouchi-son , 1♀ (4–8. VII. 2016 [ NKHU0041 ]) , 1♀ (4–7. VIII. 2016 [ NKHU0040 , Fig. 1-B ]) , MT, K. Ôhara ( EUMJ). [ Kyûshû ] Fukuoka Pref.: 1♂ , Mt. Fukuchiyama, Kitakyûshû City , 16. VII. 1969, H. Maki- hara ( SEHU); 1♀ , Mt. Tachibana, Fukuoka City , 8. VI. 1981, K. Konishi ( NIAES). Saga Pref.: 1♀ , Ideno, Mitsuse Vill. , 17. V. 1998, R. Matsumoto ( OMNH) .

Description based on Japanese specimens. Female. Body length 6.5–9.0 mm.

Coloration. Body ground color black and covered with short pale brown setae. Flagellum with white semiannulus on flagellomeres 6–9. Rarely with reddish-brown part on legs and/or basal part of metasoma. Wing veins dark brown. Metasomal T5–T7 with apical white markings.

Head. Vertex and dorsal part of gena granulated and punctate; supra-clypeal area finely granulated with dense punctures and reticulate rugose; clypeus granulated and densely punctate ( Figs 2-A–C ). Occipital carina meeting hypostomal carina just above base of mandible. HW/HL = 1.9–2.2; OW/HW = 0.6–0.7; OOL/POL = 0.9–1.0. SCW/ SCH = 1.6–1.7; CLW/CLH = 1.5–1.6. MBL/BMW = 1.9–2.2; MSL/BMW = 1.0–1.4. MP5/BMW = 1.4–1.5.

Antenna. Flagellum about as long as body length, with 31–33 flagellomeres; apical flagellomere conical; FL1 4.5–5.4 × as long as apical width and 1.4–1.5 × as long as FL2.

Mesosoma. Pronotum shallowly punctate on upper half and longitudinally rugose on lower part; mesoscutum dull, granulated and densely punctate, and median part reticulate punctate; dorsal and posterior surface of scutellum rather sparsely punctate; postscutellum polished, with sparse longitudinal rugae; mesopleuron densely punctate and reticulate rugose; metapleuron covered with strong oblique rugae; surface of propoduem roughly rugose ( Figs 2-D, E ). Dorsal surface of scutellum strongly convex ( Fig. 3-H ). Lateral carina of scutellum reaching posterior end ( Fig. 2-D ). MSSL/MSSW = 0.9–1.0; ARL/ARW = 0.4–0.8; ARW/PSD = 0.3–0.6; PSI = 1.2–1.8.

Legs. Surface of legs coriaceous, except coxae finely punctate. Hind tibia 0.4 × as long as fore wing.

Wings ( Fig. 4-A ). Fore wing 5.0– 7.5 mm long; areolet pentagonal, 1.0–1.1 × as long as 3rs-m, 0.5–0.6 × as high as 2m-cu; 1/M:2/M = 1.0:0.9–1.0. Cu-a opposite Rs&M; ramulus slightly to moderately developed. Hind wing with cu-a 0.2 × as long as first abscissa of Cu1; a basal hamulus, 7–9 distal hamuli on R1 vein.

Metasoma. Surface of petiole almost polished; postpetiole and lateral area of petiole weakly rugose; basal half of T2 roughly punctate except gastrocoelus and area between them strongly rugose; apical half of T2, whole of T3 densely punctate and coriaceous, T4–T5 coriaceous ( Figs 2-F, G ). Petiole in dorsal view almost parallel sided in basal half; postpetiole slightly widened; dorsomedian carina complete; median and lateral field of postpetiole clearly separated by dorsomedian carina. Posterior margins of T5–T7 concave ( Fig. 2-F ). S2–S4 laterally sclerotized and middle part weakly sclerotized, S5 entirely sclerotized. S2–S4 with laterosternites, S5 without laterosternite (same as males, Fig. 2-H ). T1 L/W = 1.8–1.9; T2 L/W = 0.8–1.1. THI = 1.5–1.9.

Male. Body length 7.0– 8.5 mm. As in female except for the following characters: FL1 3.5–3.8; apical margin of S8 slightly protruding at middle ( Fig. 2-H ); paramere of genitalia black, apex narrowed, apical 2/3 covered with short setae; aedeagus evenly curved toward venter, apex narrowed ( Fig. 5 ).

Diagnosis: This species can be easily distinguished from other species of the genus by combination of: head, mesoscutum and scutellum always entirely black; scutellum strongly convex; areolet pentagonal; basal half of T2 roughly rugose.

Distribution: Japan (Hokkaidô, Honshû, Shikoku, Kyûshû); Holarctic Region.

Remarks: This species comprises three subspecies, L. e. exhortator from Palearctic Region, L. e. thoracius (Cresson) from Nearctic Region, and L. e. montanus Heinrich from Nearctic Region. They are distinguished by differences of the body colorations. Japanese specimens of L. exhortator are different from both European and Nearctic population by the mostly black coloration. We also examined a specimen from Sakhalin, recorded by Uchida (1956). This specimen was mostly black, with completely reddish-brown propodeum, T1, mid and hind coxae. In addition to the coloration, according to the description of Tereshkin (2009), FL1 is 3.7 × as long as apical width in L. exhortator , whereas in Japanese specimens it is 4.5–5.4 ×. This difference may be due to measurement error. It is necessary to examine more specimens from the eastern Palearctic region to consider variations of coloration and measurements of FL1. As discussed below, here we treat Japanese specimens as Palearctic nominotypical subspecies. Some of the Japanese specimens have reddish-brown part on legs or basal part of metasoma as shown in Fig. 2-C . We examined DNA barcodes and concluded that they are intra-specific variations ( TABLE 1 ). DNA barcode of three Japanese specimens are available on BOLD dataset [DS-LINJP]. Some specimens from Sapporo, Japan were collected in agricultural fields, such as lettuce or potato fields. In these fields, they might be potential natural enemy of the pests on vegetables.

Figures

FIGURE 1. Habitus of Japanese Linycus spp. A. L. exhortator (Fabricius), female from Hitsujigaoka [NKHU0042], B. ditto, female from Hitsujigaoka [NKHU0040], C. ditto, male, from Bekanbeushi, D. L. kyoheii sp. nov., holotype (female). Scale bars = 1.0 mm.

FIGURE 2. Linycus exhortator from Japan. A–G, I: female from Hitsujigaoka [NKHU0042], H: male from Hitsujigaoka. A. head in frontal view, B. head in dorsal view, C. head in profile, D. mesosoma in dorsal view, E. mesosoma in profile, F. metasoma, in dorsal view G. metasoma in profile, H. metasomal sternites, I. 4th tarsomere of mid leg. Scale bars = 0.5 mm for A–H, 0.1 mm for I.

FIGURE 3. Linycus kyoheii sp. nov. and L. exhortator, female from Hitsujigaoka [NKHU0042]. A–G: holotype of L kyoheii sp. nov. H: L exhortator. A. head in frontal view, B. head in dorsal view, C. mesosoma in dorsal view, D. head and mesosoma in profile, E. metasoma, in dorsal view F. metasoma in profile, G, H. scutellum. Scale bars = 0.5 mm for A–F, 0.1 mm for G, H.

FIGURE 4. Wings of Japanese Linycus spp. A. L. exhortator, female from Hitsujigaoka [NKHU0042], B. L. kyoheii sp. nov., holotype. Scale bars = 1.0 mm.

FIGURE 5. Male genitalia of L. exhortator from Hitsujigaoka. A. left aedeagus in profile, B. left paramere in outer view, C. left volsella in mesal view. Scale bars = 0.1 mm.