Ishigakia exetasea Uchida, 1928

Ito, Masato & Maeto, Kaoru, 2016, Revision of Ishigakia Uchida (Hymenoptera: Ichneumonidae: Acaenitinae) from Japan, with a new species having a close relative in South Africa, Zootaxa 4136 (1), pp. 174-180 : 177-178

Ishigakia exetasea Uchida, 1928

( Figs 1 c, d, 3a–h)

Ishigakia exetasea Uchida, 1928: 33 . Lectotype: Japan, Ishigaki Is. Ishigakia exetasea: Kusigemati, 1987: 32 ; Kusigemati, 1991: 46.

Redescription of Japanese specimens. ♀ (n= 8). Body length: 11.5–13.0 mm.

Head. 0.6 × as long as wide in dorsal view. Face 0.7 × as long as wide, strongly and densely punctate, and weakly convex ( Fig. 3 a). Frons weakly punctate, with a median longitudinal carina ( Fig. 3 a). Clypeus 0.7 × as long as wide, without punctures. Malar space 1.1–1.3 × as long as basal width of mandible. Subocular groove present ( Fig. 3 a). Mandible striated except for apex ( Fig. 3 a). Gena weakly sparsely punctate. Occiput smooth. OOL/OD = 1.6–1.9. POL/OD = 0.9–1.1. Antenna with 31 or 32 flagellomeres; first flagellomere 1.3–1.4 × as long as second flagellomere.

Mesosoma ( Fig. 3 b, c). Propleuron densely punctate. Lateral area of pronotum densely punctate and transversely striated medially. Collar densely punctate. Mesoscutum strongly and densely punctate. Scutellum sparsely punctate, weakly convex in lateral view. Metapleuron sparsely punctate. Propodeum strongly carinate, roundly convex in lateral view ( Fig. 3 b). Area basalis polished. Area externa, area dentipara and area superomedia punctate. Area petiolaris polished. Propodeal spiracle elongate ( Fig. 3 b). Fore wing: length 11.5–13.0 mm. Vein cu- a basad of vein M+cu ( Fig. 3 e). Vein 3 rs-m distad of vein 2 m-cu ( Fig. 3 e). Hind wing with vein cu-a intercepted above the middle ( Fig. 3 f). Hind femur 3.3–3.9 × as long as maximum depth in lateral view, with a blunt ventral tooth. Hind tibia 10.2–10.6 × as long as maximum depth. First hind tarsomere 3.2–3.4 × as long as second, 2.4–2.8 × as long as inner spur.

Metasoma ( Fig. 3 d). T1 1.9–2.4 × as long as maximum width, 1.9–2.4 × as long as T2. T2 1.0–1.1 × as long as maximum width. Tergites weakly punctate. Ventral swelling of S1 with erect setae. Ovipositor sheath 1.4–1.5 × as long as hind tibia.

Coloration ( Fig. 1 c). Yellowish brown. Antennal flagellum without a white band. Apical part of mandible, fifth hind tarsomere and hind tarsus claws brown. Mesosoma and metasoma with many brown markings. Fore wing with a dark marking on apical margin ( Fig. 3 e).

♂ (n=30). Similar to females except as follows. Body length: 10.5–11.0 mm. Face 0.6–0.7 × as long as wide. Clypeus 0.6 × as long as wide. Malar space 1.3–1.5 × as long as basal width of mandible. Antenna with 32–34 flagellomeres; first flagellomere 1.2–1.4 × as long as second flagellomere. Hind femur 3.4–4.0 × as long as maximum depth in lateral view. Hind tibia 9.0–10.2 × as long as maximum depth. Area externa and area dentipara rugose. First hind tarsomere 2.7–3.0 × as long as second, 2.7–3.0 × as long as inner spur. T1 3.3–3.4 × as long as maximum width, 1.7–2.0 × as long as T2. T2 1.4–1.9 × as long as maximum width.

Genitalia (n=3). Subgenital plate pentagonal with a basal angle obtuse ( Fig. 3 g), its length ca. 0.9 × as long as aedeagus. Paramere short, basal part strongly projected toward the base of subgenital plate ( Fig. 3 h). Aedeagus gently curved in lateral view, its penis valve ca. 1.3 × as long as basal apodeme.

Specimens examined. Japan, Okinawa Pref.: 1♂ (lectotype of Ishigakia exetasea ), Ishigaki Is., August 1922, S. Hirayama ( SEHU); 2♂, Mt. Omoto-dake, Ishigaki Is., 18 April 1978, E. Nishida ( OMNH); 2♂, Mt. Buzamadake, Ishigaki Is., 11 May 2014, M. Ito ( SEHU); 3♂, Uehara, Iriomote Is., 3 May 1980, E. Nishida ( KPMNH); 5♂; same locality, 4 May 1980, E. Nishida ( SEHU); 1♀ 2♂, same locality, 16–18 May 2013, Y. Nakatani ( NSMT); 1♀, same locality, 15 May 2014, M. Ito ( OMNH); 4♀ 7♂, Funaura, Iriomote Is., 5 May 1980, E. Nishida ( SEHU); 1♂, same locality, 12 May 2008, T. Ban ( KPMNH); 1♂, Urauchi-gawa, 13 May 2008, K. Watanabe ( KPMNH); 1♀ 1♂, same locality, 22 May 2011, K. Watanabe ( KPMNH) (Genbank accession number AB932955 , Ito & Maeto, 2014); 1♂, Otomi-rindo, Iriomote Is., 20 May 2007, T. Ban ( KPMNH); 1♂, same locality, 11 May 2008, K. Watanabe ( KPMNH); 1♂, Komi, Iriomote Is., 11 May 2008, T. Ban ( KPMNH); 1♂, Maera-gawa, Iriomote Is., 2 May 2007, H. Kawai ( KPMNH); 1♀, Iriomote, Iriomote Is., 16–18 May 2013, Y. Nakatani ( NSMT).

Distribution. Japan (Ryukyus: Ishigaki Is. and Iriomote Is.*), Taiwan ( Kusigemati, 1987, 1991). * New record.

Bionomics. Host unknown. Adults were mainly collected in May. Females and males were observed visiting Japanese silvergrass ( Miscanthus sinensis Andersson ), along forest edges or in the ridges between sugarcane fields, and some females tapping ( Fig. 4 ) and inserting the ovipositor into small clefts on withered silvergrasses on Ishigaki Is. in May, 2014.

Remarks. The females of this species are described here for the first time, and have a short ovipositor, less than twice as long as hind tibia, as in many other congeners ( Roman, 1910; Sheng & Sun, 2010) except for I. maculata ( Sun & Sheng, 2009) .

Figures

FIGURE 1. Habitus. Ishigakia exetasea (Uchida), female from Iriomote Is. (a), and male from Iriomote Is. (b). Ishigakia albitarsa sp. nov., female holotype from Tottori Pref. (c), and male paratype from Shizuoka Pref. (d). Scale bar = 5.0 mm.

FIGURE 3. Ishigakia exetasea Uchida, female (a-f) and male (g, h) from Iriomote Is. a, Head, frontal view; b, mesosoma, lateral view; c, mesosoma, dorsal view; d, metasoma, lateral view; e, right fore wing; f, right hind wing; g, subgenital plate, ventral view; h, genital capsule, ventral view.

FIGURE 4. Female Ishigakia exetasea, tapping on withered Japanese silvergrass at Omoto-dake, Ishigaki Is., on May 21, 2014.