Epicephala corruptrix, Kawakita, Atsushi & Kato, Makoto, 2016

Kawakita, Atsushi & Kato, Makoto, 2016, Revision of the Japanese species of Epicephala Meyrick with descriptions of seven new species (Lepidoptera, Gracillariidae), ZooKeys 568, pp. 87-118 : 99-102

Taxon classification Animalia Lepidoptera Gracillariidae

Epicephala corruptrix sp. n. Figs 1, 2, 3, 4, 5, 6, 7

Clade 4 ( Kawakita and Kato 2006); Epicephala sp. ex Glochidion rubrum ( Kawakita and Kato 2009; Kawakita et al. 2015); Epicephala sp. 4 ( Glochidion rubrum ) ( Kawakita et al. 2010).

Diagnosis.

The male genitalia of this species are distinctive and have no parallel in other known species; sacculus possesses a thick spine on apex and a cluster of long spines on dorsal projection. The large, round lamella postvaginalis also distinguishes this species from other known Epicephala .

Description.

Wingspan: 7.2-8.8 mm.

Head: With numerous white scales on dorsal surface. Labial palpus dark brown. Antenna brown, about 1.2 × as long as forewing. Female proboscis with a large number of trichoid sensilla; sensilla 1.5 × as long as width of proboscis, denser toward base.

Thorax: White dorsally. Forewing brown with narrow white band on dorsum from base to 2/3 of entire length; two pairs of narrow white bands beginning at costal and dorsal margin near 1/2 to 3/4 length of wing and extending obliquely toward wing apex, terminating before reaching mid-width of wing; dorso-distal band accompanied by another parallel band of same size on distal position; a narrow silver band with metallic reflection extending from costa to dorsum at 5/6 length; distal 1/6 orange-brown with black dot centrally, franked by short white band near dorsum; distal end fringed with narrow white band; cilia grayish brown. Hindwing brown, 0.8 × length of forewing; cilia grayish brown.

Male genitalia: Tegumen oblong, acute at apex. Cucullus rectangular oblong; ventral margin with acute tip at mid-length terminating with short spine; inner surface covered with numerous hairs. Sacculus ovoid; apex sharply concave, with a long spine on ventral half; basal part of dorsal margin attached with a narrow plate terminating distally as an inward, finger-like projection with 3 or 4 long spines directing dorso-ventrally. Vinculum U-shaped; saccus broad, 0.3 × width of vinculum, as long as vinculum, oblong and acute at apex. Aedeagus straight, slightly dilated toward apex; cornutus absent.

Female genitalia: Lamella postvaginalis long and broad, 0.8 × width and length of seventh sternite, coarsely dentate at distal end. Antrum broad, 0.4 × width and length of lamella postvaginalis, smooth on surface. Ductus bursae as long as seventh sternite, with cluster of longitudinal parallel ridges for its entire length. Corpus bursae oval to elongate oval, as long as buctus bursae; signum absent. Apophyses posteriores 1.5 × length of apophyses anteriores. Ovipositor dentate laterally, angular at apex.

Material examined.

22♂, 5♀. Holotype ♀ - JAPAN: Okinawa Prefecture: Okinawa Island, Takae (26.652878, 128.248178), 100 m, collected as larva in galled flower of Glochidion obovatum and reared to adult, 5.vi.2015 (KYO). Paratypes - same data as holotype, 10♂, 2♀ (KYO). Other specimens - JAPAN: Kagoshima Prefecture: Amami Island, Akakina, 4.xi.2004, 5♂, 1♀; Amami Island, Kise, 15.iv.2006, 3♂, 1♀; Amami Island, Kasari, 18.v.2015, 1♂; Tokunoshima Island, Mikyo, 2.xi.2004, 1♂; Okinawa Prefecture: Iriomote Island, Ohara, 14.ii.1998, 2♂ (M. Kato).

DNA barcodes.

DQ298999, DQ299000, DQ299006, DQ299007, DQ299015-DQ299018, DQ299022, DQ299024-DQ299027.

Known host and adult behavior.

Glochidion obovatum (Amami Island, Tokuno Island and Okinawa Island) and Glochidion rubrum (Ishigaki Island and Iriomote Island). The egg is laid through the ovary wall between the wall and ovule (Fig. 8G). Pollination behavior is present, but in the resulting fruit, the larva galls one of the locules, inducing abnormal development of the ovules (Fig. 11). Such fruits usually do not contain normally developed seeds (Fig. 11).

Distribution.

Restricted to several islands in the Ryukyu Archipelago (Amami Island, Tokuno Island, Okinawa Island, Ishigaki Island and Iriomote Island; Fig. 9D).

Etymology.

The species name corruptrix (a noun in apposition) was inherited from Tegeticula corruptrix , a derived parasitic species of yucca moth (Pellmyr et al. 1999). Epicephala corruptrix has a potential to corrupt the mutualistic relationship with its host because the species induces gall formation in pollinated flowers which then hardly produce seeds (Fig. 11).

Remarks.

This species shares the same host plant with Epicephala obovatella , but Epicephala obovatella has not been collected from any of the locations where Epicephala corruptrix occurs (Fig. 9). Because of the limited mutualistic potential of this species, reproduction of the host plants ( Glochidion obovatum and Glochidion rubrum ) is likely to be severely limited on islands where Epicephala corruptrix occurs, in comparison to locations where Epicephala obovatella is present.