Andricus formosanus Tang & Melika

Tang, Chang-Ti, Melika, George, Yang, Man-Miao, Nicholls, James, Csóka, György & Stone, Graham N., 2009, First record of an Andricus oak gallwasp from the Oriental Region: a new species from Taiwan (Hymenoptera: Cynipidae: Cynipini), Zootaxa 2175, pp. 57-65 : 58-64

Andricus formosanus Tang & Melika , new species

Figs 1–16

Type material. HOLOTYPE female: TAIWAN, Pingtung County, I-Chang Mountain, Wutai Township, ex Q. dentata , leg. Yu -F e n g H s u. PARATYPES: 12 males and 44 females: 29 females with the same label as the holotype; 8 male and 8 female paratypes: TAIWAN, Pingtung County, I-Chang Mountain, Wutai Township, ex Q. dentata , leg. Chang-Ti Tang, 2009. III.15. adult em. 2009. III.23; 4 male and 7 female paratypes: TAIWAN, Taichung County, Shinshou Township, ex Q. dentata , leg. Chang-Ti Tang, 2009. III.25., adults em. 2009. III.25. The holotype female, 10 female and 3 male paratypes are deposited in NMNS; 10 female and 3 male paratypes in NCHU, 5 female and 2 male paratypes in USNM; 19 female and 4 male paratypes in PDL.

Etymology. The species is named after Formosa, an earlier name for the island of Taiwan.

Diagnosis. Most closely resembles Andricus moriokae Monzen. In Andricus formosanus , new species the female antenna has 12 flagellomeres, with dense white setae; the forewing with a distinct areolet, the mesoscutum is much shorter in dorsal view; 2nd metasomal tergite with numerous setae antero-laterally; the prominent part of the ventral spine of the hypopygium is longer, while in A. moriokae the female antenna has 11 flagellomeres, with few sparse short white setae; the forewing without areolet, the mesoscutum longer in dorsal view; 2nd metasomal tergite with very few setae antero-laterally; the prominent part of the ventral spine of the hypopygium is shorter ( Figs 18–22 ).

Description. SEXUAL FEMALE (holotype). Head, except light brown lower face, dark brown; antenna light brown; mesosoma and metasoma dark brown, legs uniformly light brown.

Head alutaceous, with few white setae, more dense on lower face, genae and occiput; 2.0 times as broad as long from above, 1.4 times as broad as high and as broad as mesosoma in front view. Gena alutaceous, not broadened behind eye, narrower than cross diameter of eye; malar space alutaceous, without striae, 0.4 times as long as height of eye. POL nearly 1.5 times as broad as OOL; OOL 2.1 times as long as length of lateral ocellus and 1.4 times as long as LOL. Transfacial distance only 1.1 times as broad as height of eye; diameter of antennal torulus 1.5 times as large as distance between them, distance between torulus and inner margin of eye 1.2 times a long as diameter of torulus; lower face alutaceous, with dense white setae, the median elevated area coriaceous. Clypeus rounded, emarginated, without median incision ventrally, delicately coriaceous, with very small elevated central area; anterior tentorial pits indistinct, epistomal sulcus and clypeo-pleurostomal line distinct, deep. Frons alutaceous, with small smooth shining impression below median ocellus, with few white setae; interocellar area microreticulate. Vertex and occiput delicately coriaceous to alutaceous. Postocciput alutaceous, impressed around occipital foramen, without setae; posterior tentorial pits small, rounded, deep, area below them not impressed; height of occipital foramen slightly larger than height of gula; hypostomal carina emarginated, not going around oral foramen, continuing into gular sulcus. Labial palpus 3–segmented, all three segments densely setose; maxillary palpus 5-segmented, three terminal segments densely setose. Antenna with 12 flagellomeres; slightly longer than mesosoma; pedicel slightly longer than broad; F1 1.2 times as long as F2, 1.7 times as long as pedicel; F2-F5 equal in length, F6–F10 shorter than previous flagellomeres and subequal in length; F12 slightly longer than F11; placodeal sensilla on F2–F12, absent on F1–F2.

Mesosoma convex, only 1.2 times as long as high. Pronotum dull rugose, with numerous striae laterally, with dense white setae, emarginated along ventro-lateral edge, followed by deep longitudinal invagination; anterior rim of pronotum brown, laterally broader, with numerous longitudinal striae; propleuron light brown, alutaceous, shining, with smooth area in center, concave in medio-central part. Mesoscutum delicately alutaceous to smooth, especially in between notauli, shining, antero-laterally possess a patch of dense white setae; slightly broader than long (largest width measured across mesoscutum on the level of the base of tegulae). Notauli complete, deep and narrow, distinctly impressed, slightly converging and broadened at the posterior end; anterior parallel and parapsidal lines invisible, even rows of setae do not indicate them; median mesoscutal line absent. Mesoscutellum 0.7 times as long as mesoscutum, rounded, uniformly dull rugose, with irregular strong rugae, subequal, nearly as long as broad, very slightly overhanging metanotum; scutellar foveae distinct, transversely ovate, nearly 2.0 times as broad as high, with smooth, shining bottom, with distinct elevated narrow smooth median carina, separating foveae. Mesopleuron and speculum darker than rest of mesosoma, smooth, shining, without setae; narrowly impressed along acetabular carina; dorsal axillar area smooth, shining, with few strong irregular rugae and dense white setae; lateral axillar area alutaceous, with few setae; subaxillular bar dark brown, smooth, shining, in the most posterior part shorter than height of metanotal trough; postalar process light brown, with parallel delicate striae; metapleural sulcus reaching mesopleuron in the upper 1/3 of its height. Metascutellum dark brown, uniformly coriaceous,

metanotal trough brown, with some irregular rugae, with dense short white setae; ventral impressed area nearly as high as height of metascutellum, dark brown, smooth, with distinct longitudinal striae; propodeum brown, lighter than mesosoma, central propodeal area smooth, shining, with few irregular wrinkles and rugae, lateral propodeal carinae strong, high, curved outwards in posterior 1/3; lateral propodeal area with dense long white setae. Nucha with irregular wrinkles and rugae, brown.

Tarsal claws with basal lobe. Forewing longer than body, hyaline, with distinct long dense cilia on margin, radial cell 3.9 times as long as broad; R1 not reaching wing margin, Rs nearly straight, nearly reaching wing margin; areolet large, triangular, closed and distinct. Rs+M distinct on 2/3 of distance to basalis and its projection reaching basalis at its half height.

Metasoma slightly longer than head+mesosoma, higher than long in lateral view; 2nd metasomal tergite occupying 2/3 of metasoma length in dorsal view, with dense white setae laterally, all tergites without setae, smooth, shining. Ventral spine of hypopygium slender, prominent part at least 3.0 times as long as broad, with sparse, long white setae, not extending beyond the apex of spine. Body length 2.1–2.4 mm (n=30).

MALE. 2.1–2.3 mm (n=12) similar to female but head and mesosoma black, metasoma very dark brown to black; antenna with 13 flagellomeres, slightly longer than body length, F1 only slightly curved, apically swollen, 1.4 times as long as F2, placodeal sensilla on all flagellomeres.

Gall ( Figs 14–16 ). Individual galls are approximately spherical, 3.5–5.0 mm in height (n=8), and integral to the leaf lamina. Galls cause swelling on both upper and lower surfaces of the leaf, and each contains a single(unilocular) thin-walled larval chamber 1.5–1.7 mm in diameter (n=8), attached by a tiny filament to the outer wall of the gall. In mature galls, the larval chamber loses its connection to the gall wall, and rolls freely within an internal air space. Though galls can occur separately on a leaf, they are often aggregated into masses 20–70 mm long that distort the leaf blade. Young galls are fleshy and pale green to yellowish, remaining soft as they mature.

Biology. Only the sexual generation of this species is known, inducing aggregated integral leaf galls on Quercus dentata (Section Quercus sensu stricto). Mature galls were collected in March, adults emerged immedeately after the galls were collected, in late March. Most oak cynipids show cyclically parthenogenetic alternation of generations ( Stone et al. 2008, 2009), following a spring sexual generation with an asexual generation developing through the summer and early autumn. All Andricus species with sexual generations on section Quercus sensu stricto oaks known to date have an asexual generation on oaks in the same taxon, and it is probable that the partner asexual generation will also be found on Q. dentata .

Distribution. Currently known only from Taiwan: Taichung County, near Shinshou and Tungshih, and upstream of north Ailiao stream in Pingtung County, the only two places where Q. dentata is known in Taiwan ( Lu et al. 2006) ( Fig. 17 ). It is possible that this species also occurs in continental China, as well as in Japan and/or the Russian Far East, where Q. dentata is a common species. However, Andricus formosanus was not mentioned in studies of Japanese oak gallwasps by Yukawa & Masuda (1996) and of the Russian Far East fauna by Kovalev (1965). Further research is necessary to establish the distribution of this species.

Comments. As we mentioned above, Andricus formosanus most closely resembles an Eastern Palaearctic species, Andricus moriokae Monzen , which was originally described based on the sexual generation. This species also induces integral leaf galls on Q. dentata and Q. serrata Murray (= Q. glandulifera Blume ) and is known from Japan and Russian Far East ( Monzen 1953; Kovalev 1965). Although the galls induced by the two species are structurally similar, in A. formosanus the gall clusters always much bigger, comprising many galls, often merged together, while in A. moriokae only a few galls are typically found on each leaf. For A. moriokae the alternate asexual generation is known to induce bud galls on Q. serrata ( Katsuda & Yukawa 2003) . The asexual generation of A. formosanus may be induced in a similar location on Q. dentata .

Figures

FIGURES 1 – 8. Andricus formosanus, new species: 1, head, female (front view); 2, head, female (dorsal view); 3, head, female (posterior view); 4, antenna, female; 5, antenna, male; 6, mesosoma, female (dorsal view); 7, mesosoma, female (lateral view); 8, hind tarsal claw, female.

FIGURES 9 – 13. Andricus formosanus, new species, female: 9, propleuron (front view); 10, metascutellum and propodeum (postero-dorsal view); 11, forewing; 12, metasoma (lateral view); 13, ventral spine of hypopygium (lateral view).

FIGURES 14 – 17. 14 – 16, Andricus formosanus, new species, galls: 14 – 15, general appearance; 16, dissected galls (photos Chang-Ti Tang); 17, map of Quercus dentata and Andricus formosanus distribution (google. earth. com).

FIGURES 18 – 22. Andricus moriokae, female: 18, antenna; 19, mesosoma (dorsal view); 20, forewing, part (arrow indicates the absence of areolet); 21, metasoma (lateral view) (arrow indicates the absence of lateral setae on 2 nd metasomal tergite); 22, ventral spine of hypopygium (lateral view).