Dolichogenidea maetoi Fernandez-Triana & Shimizu, 2018

Fernandez-Triana, Jose, Sakagami, Kota & Shimizu, So, 2018, Dolichogenidea maetoi sp. nov. (Hymenoptera: Braconidae) from Japan, the first parasitoid wasp recorded from Hyblaea fortissima (Lepidoptera), Acta Entomologica Musei Nationalis Pragae 58 (1), pp. 167-175 : 168-170

Dolichogenidea maetoi Fernandez-Triana & Shimizu sp. nov. ( Figs 2 A–F)

Type locality. Japan, Fukui Prefecture, Echizen City, Mount Hinoyama, 35°51′N, 136°11′E; 169 m alt. ( Fig. 1 ).

Type material. HOLOTYPE: ♀, “ Japan: Fukui-pref. / Echizen-city, Mt. Hino- / yama , alt. 169m / N:35°51’43, E:136°11 / ’ 30, 24.V.2017 emgd / K. Sakagami leg. // Host species: Hyblaea / fortissimo / ( Hyblaeidae ) / 14.v.2017, host Coll. / Host code: 6 // CNC923448 // HOLOTYPE / [ Microgastrinae ] / Dolichogenidea maetoi / Fernandez-Triana & Shimizu / Acta. Entomol. Mus. Natl. Pragae, 58: 167–175.” ( CNC) . PARATYPES: 121 ♀♀ 90 same data as holotype, but deposited in CNC, EUM, KPMNH, NIAES, NMPC, NSMT and SEHU.

Diagnosis. This species can be distinguished from all 154 previously described species of Holarctic Dolichogenidea by the unique combination of characters as follows: antennal flagellomeres, coxae and metafemur all dark brown to black; tegula and humeral complex dark brown; pterostigma brown with relatively large, pale spot at base; propodeal areola only defined by carinae on posterior half; T1 mostly sculptured on lateral margins and posterior half, and more or less parallel-sided to very slightly barrel-shaped; T2 broadly rectangular and partially sculptured, especially near margins; vein R1 longer than pterostigma; ovipositor sheaths clearly shorter than metatibia (around 0.8 times its length). Although there is no available key that covers all Holarctic Dolichogenidea , all previously described species differ from the diagnosis here provided for D. maetoi sp. nov. by at least one (usually more) characters. To facilitate future work on the genus we provide one-to-one comparisons of Dolichogenidea maetoi Fernandez-Triana & Shimizu sp. nov. with every other previously described species of Dolichogenidea in the Holarctic (see below).

There were four previously described species of Dolichogenidea in Japan; they differ from D. maetoi sp. nov. as follows: Dolichogenidea asotae (Watanabe, 1932) has meso- and metafemora reddish-yellow, sternites and laterotergites 1–3 reddish-yellow, T2 mostly sculptured, and ovipositor sheath much shorter (approximately 0.5 times) than metatibia. Dolichogenidea baoris (Wilkinson, 1930) has pterostigma pale with thin brown margins, and it is a much smaller species (body length 1.5 mm). Dolichogenidea dilecta (Haliday, 1834) has the propodeum mostly polished and without areola (only small rugae above nucha), T1 strongly narrowing towards posterior margin, T1 (basal half) and T2 (centrally) smooth, and mesofemur mostly yellow. Dolichogenidea lacteicolor (Viereck, 1911) has the propodeum with areola completely defined by carinae, including strong transverse carinae forking around spiracles, and T1 and T2 much more strongly sculptured (especially T2 which is strongly striated longitudinally).

Description. Female. Antennal flagellomeres, all coxae and metafemur dark brown to black; metatibia pale in anterior half, dark in posterior half; metatibial spurs yellow; tegula and humeral complex dark brown; pterostigma brown with relatively large pale spot at base; veins mostly brown; apical flagellomeres slightly longer than wide (1.1–1.2 times as long as wide); scutellar disc mostly smooth; polished area of lateral face of scutellar disc (lunules) approximately half the height of lateral face; propodeum mostly smooth, but with some punctures on anterior half, surrounding the areola; propodeum areola only defined by carinae posteriorly (anterior half defined by an impression); T1 more or less parallel-sided to very slightly barrel-shaped (i.e., slightly wider centrally as compared to narrower anterior and posterior margins – anterior and posterior margins of similar or very similar width); T1 mostly sculptured on lateral margins and posterior half; T1 1.55–1.70 times as long as wide at posterior margin; T2 partially sculptured, especially near margins; T2 relatively transverse and rectangular (T2 width at posterior margin 2.85–3.00 times its length medially); T3 longer than T2 (T3 L 1.25–1.38 times T2 L); pterostigma 2.35–2.50 times as long as wide; vein R1 longer than pterostigma (R1 L 1.10–1.20 times pterostigma L); ovipositor sheath slightly curved downwards, and slightly widening towards apex; ovipositor sheath clearly shorter than metatibia (ovipositor sheath 0.70–0.80 times metatibia length).

Body measurements (all in mm). Body L: 2.5 (2.4–2.6); forewing L: 2.7 (2.6–2.9); ovipositor sheath L: 0.64 (0.60–0.69); F2/3/14/15 L: 0.21/0.20/0.08/0.08 (0.22– 0.24/0.21–0.23/0.09/0.09); metafemur L/W: 0.75/0.24 (0.71–0.84/0.23–0.26); metatibia L: 0.83 (0.83–0.99); metatibia inner/outer spur L: 0.20/0.15 (0.20–0.23/0.14–0.17); first segment of metatarsus L: 0.41 (0.40–0.45); T1 W at anterior margin/maximum W/W at posterior margin/L: 0.25/0.27/0.24/0.41 (0.26–0.28/0.29–0.30/0.27–0.28/0.42– 0.44); T2 W at posterior margin: 0.39 (0.42–0.45); T2 L medially: 0.13 (0.14–0.16); T3 L medially: 0.18 (0.18– 0.20); pterostigma L/W: 0.52/0.22 (0.58–0.62/0.23–0.25); vein R1 L: 0.62 (0.64–0.73).

Male. As female but T2 more subtriangular, and overall body sculpture less marked.

Etymology. The species is named to honour Professor Kaoru Maeto, a great Japanese braconid researcher, and the professor at the laboratory the second (KS) and third (SS) authors of this paper are connected with.

Biology. The type series was reared from larvae of Hyblaea fortissima on its host plants ( Callicarpa mollis and C. japonica ) ( Fig. 1 ). Nine out of 20 host larvae we studied were parasitized by D. maetoi sp. nov.; parasitism rate was 45%. The number of wasps emerged from a single host larva was 27.6 ± 2.7 (mean ± SE; range 14–40; n = 9). The female sex ratio was 0.65; significantly female-biased (binomial test, P <0.05). However, the female sex ratio varied between different host larvae, ranging from 0.14 to 0.88. In six out of nine host larvae there was a significantly biased female sex ratio, whereas one host larva was male biased and the sex ratio was not biased in two larvae.

The sex ratio of parasitoid wasps is sometimes influenced by various factors, such as parental age ( UÇKAN & GÜLEL 2002, GÜNDÜZ & GÜLEL 2005), host body size ( CHARNOV et al. 1981, SANTOLAMAZZA- CARBONE et al. 2007), and host age ( CHARNOV et al. 1981).

Distribution. Japan (Fukui Prefecture).

Figures

Fig. 2. Female paratype of Dolichogenidea maetoi Fernandez-Triana & Shimizu sp. nov.A – habitus, lateral; B – head, frontal; C – wings; D – metasoma, dorsal; E – mesosoma, dorsal; F – antenna.

Fig. 1. Caterpillar of Hyblaea fortissima Butler, 1881, host of Dolichogenidea maetoi Fernandez-Triana & Shimizu sp. nov. A – leaf shelter; B – host caterpillar in the shelter.