Digitivalva bella Zhang, Yagi & Hirowatari, 2024

Zhang, Xinyu, Yagi, Sadahisa & Hirowatari, Toshiya, 2024, A remarkable new species of the genus Digitivalva Gaedike, 1970 (Lepidoptera, Glyphipterigidae, Acrolepiinae) from Japan, Nota Lepidopterologica 47, pp. 187-199 : 187-199

Digitivalva bella Zhang, Yagi & Hirowatari sp. nov.

Figs 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 Japanese name: Hiiro-ginsuji-koga

Digitivalva sp.: Suzuki et al., 2018: 23.

Material examined.

Holotype. JAPAN • ♂; [Shizuoka Pref.], Tarai-misaki Toji, Shimoda-shi ; 28. III. 2022; S. Yagi, T. Hirowatari, HK Kim leg (Host: Carpesium divaricatum, Japanese name: Gankubisou); 11. IV. 2022 em.; ELKU.

Paratypes. JAPAN - HOKKAIDO • 1 ♀; Hokkaido Pref., Mt. Apoi , 23. VI. 1959; T. Kumata leg.; SEHU . - HONSHU • 1 ♀; Ishikawa Pref., Komatsu City, Awazu , 21. X. 2022, A. Tomisawa leg.; ELKU • 1 ♂; same locality as holotype, Prep. 176413 Lb 13. IV. 2017 T. Suzuki leg. ( ELKU) ; • 20 ♂♂ 15 ♀♀; from the same locality, collection date, and collectors as the holotype; 28. III. 2022; S. Yagi, T. Hirowatari, HK Kim leg.; 5–15. IV. 2022 em.; Host: Carpesium divaricatum , genitalia on slide Nos. XZG- 16, XZG- 17, XZG- 25, XZG- 27, XZG- 28, XZG- 29, XZG- 30, XZG- 31, XZG- 32, XZG- 35, XZG- 36, XZG- 37, wing venation on slide Nos. XZW- 3, XZW- 4, XZW- 5, XZW- 6, XZW- 7, XZW- 8; ELKU • 1 ♂; same locality as holotype; 13. IV. 2023; S. Yagi, leg.; 17. IV. 2023 em.; Host: Carpesium divaricatum ; ELKU • 2 ♂♂ 3 ♀♀; Aichi Pref., Seto-shi, Higashishirasaka-cho, Mt. Sanage-yama ; 3–5. IX. 1980; Y. Arita leg.; resting on flowers of Eupatorium chinense L. var. simpliciforium, Japanese name: Hiyodoribana, Yutaka Arita Collection, NSMT Donation, 2004, (♂ Genitalia on slide No. 669, Y. Arita, 1980; NSMT • 2 ♀; Aichi Pref., Kitashidara-gun, Uradani (900 m); 31. VIII. 1975; Y. Arita leg.; Yutaka Arita Collection, NSMT Donation, 2004, Genitalia on slide No. 314, Y. Arita, 1977; NMST • 1 ♀; Wakayama Pref., Nati ; 27. V. 1964; T. Kumata; SEHU.

- SHIKOKU • 1 ♀; Ehime Pref., Omogo-kei ; 15. VI. 1956; M. Okada leg.; Yukata Arita Collection, NSMT Donation, 2004; NSMT .

- KYUSHU • 1 ♀; Fukuoka Pref., Hikosan ( Buzen ); 19. VII. 1955; H. Kuroko; “ Gankubiso no miner ” [= miner of Carpesium divaricatum ] genitalia on slide No. XZG- 20; OPU • 1 ♂ 1 ♀; same data except 20. VII. 1955; OPU • 1 ♂, same locality; 21. VII. 1955; H. Kuroko; “ Gankubiso no miner ” [= miner of Carpesium divaricatum ]; genitalia on slide No. XZG- 24; OPU • 1 ♂ 1 ♀; same data except 24. VII. 1955; OPU • 1 ♂; same data except 26. VII. 1955; OPU • 1 ♂; same data except 13. IX. 1955; OPU • 2 ♂; same data except 28. VII. 1957; OPU • 1 ♂ 1 ♀; same data except 29. VII. 1957; OPU • 1 ♂ 1 ♀; same data except 31. VII. 1957; OPU • 1 ♂ 1 ♀; same data except 1. VIII. 1957; OPU • 2 ♂ 2 ♀; same data except 3. VIII. 1957; OPU .

Immature stage, fixed and preserved in ethanol 70 %: pupa, same locality as holotype, 13. IV. 2023, S. Yagi, leg., Host: Carpesium divaricatum ; ELKU.

Diagnosis.

This species can be easily distinguished from other Digitivalva species by its bright orange colour with silvery-white stripes on the forewing. The male genitalia are similar to those of D. arnicella ( Heyden, 1863) by sharing the absence of a horizontal split in the costal arm of the valva and developed sacculus, and the broad vinculum-saccus combination. Male genitalia of this species can easily be distinguished from those of other Digitivalva species by possessing a single vertical split on each costal arm of the valva and a C-shaped valva (sacculus broad, extraordinary in D. arnicella ). The female genitalia are similar to those of D. arnicella in the absence of a signum; however, this species can be distinguished by the ovally rounded ostium bursae (triangular in D. arnicella ).

Description.

Male (Fig. 1 A , 2 A ). Wingspan: 11.5 mm in holotype, 9.0–12.0 mm in paratypes (n = 36). Forewing length: 5.0 mm in holotype, 3.5–6.0 mm in paratypes (n = 36). Head: vertex covered with bright yellowish orange scales, scattered with several white scales; frons dark grey. Collar grey, with orange scales, edged anteriorly, orange slender scales behind compound eyes on both sides. Antenna approximately 3 / 4 of forewing length; scape and pedicel smooth, orange; flagellum black; each flagellomere ringed yellow posteriorly. Labial palpus yellowing orange with dark grey rings; the long, slightly curved tip.

Thorax bright orange; metathorax with black slender scales; tegula basically bright orange with black scales on the tip.

Forewing ground colour bright orange; 4 wide black-edged silvery white stripes distributed averagely from base to 3 / 5: basal line near the base, separated into 2 slender white dots, not reaching posterior margin; antemedial line wide, black-edged white, started at 1 / 5 of costal margin, reaching posterior margin; median line similar to antemedial line, started at 1 / 3 of costal margin; postmedial line complete or sometimes broken into 2 or 3 segments, black-edged white, starting at 1 / 2 of costal margin, attached to a black anal dash near posterior margin; subapically with two black-edged white stripes at 2 / 3 and 4 / 5 of costal margin, not reaching half of forewing width; anal dash triangular, black with small white dots scattered, reaching terminal line; apical dash relatively smaller, triangular, black with small white dots scattered; outer margin dark fuscous. Fringe dark brown, white in the middle of outer margin.

Hindwing ground colour khaki grey to brownish grey with one stout frenulum in male; posterior smoothly rounded; greyish-white scales present between the costal margin and median cell. Fringe greyish khaki, apical half light grey; fringe length gradually increasing from apex to posterior base.

Legs black; tarsomeres ringed with yellowish-white.

Wing venation (Fig. 2 A, B ). Forewing: Sc connected with costal margin in the middle. R 1 from basal 1 / 3 of cell; all radical veins separated; areole present in discal cell; R 5 slightly below apex. M 1 and M 2 parallel; M 3 from lower angle of discal cell. CuA 1 and CuA 2 from lower angle of discal cell separated, rather close at the base; CuP present, reaching posterior margin. 1 A + 2 A running to 2 / 3 of posterior margin. Hindwing: Sc + R 1 connected with costal margin at basal 4 / 5. Rs running to near apex; M 1 and M 2 stalked. M 3 and CuA 1 stalked; CuA 2 from lower angle of discal cell; CuP reaching posterior margin. 1 A + 2 A running to 1 / 3 of posterior margin; 3 A present.

Abdomen dark yellowish-grey.

Female (Figs 1 B , 2 B ). Wingspan: 8.0–12.0 mm in paratypes (n = 32). Forewing length: 3.5–6.0 mm in paratypes (n = 32). No sexual dimorphism exists. Female sometimes darker in colour than males. Hindwing with two slender frenular bristles.

Male genitalia (Fig. 3 A – D ). Tuba analis wide, triangular, membranous, curved downward in lateral view. Anellus well sclerotised. Valva symmetric, well sclerotised; sacculus produced; costal arm developed with vertical single split at apex, forming the whole valva into C-shaped; long stiff setae covering both sacculus and costal arm at apex. Vinculum strongly sclerotised, round V-shaped; saccus weakly submembranous, not obvious. Phallus curved ventrally in lateral view, and broad anteriorly; bulbus ejaculatorius relatively oval-shaped.

Female genitalia (Fig. 4 A, B ). Papilla analis nearly triangular, clothed with both short- and medium-stiff hairs, and submembranous. Intersegmental membrane between seventh and eighth sterna has a symmetric, strongly sclerotized triangular sterigma. Ostium bursae ovally rounded. Ductus bursae rather long, moderately membranous; corpus bursae attached to the end of ductus bursae membranous, oval, without signum. Ductus seminalis attached to posterior portion of corpus bursae near the end of ductus bursae, long, broaded at attaching point to corpus bursae, membranous.

Pupae (Figs 5 A – C , 7 E – G ). Length 6.5–7.5 mm; width approximately 1.5 mm (n = 11, including exuviae). General colouration of pupal exuviae yellowish-brown. Body nearly cylindrical, fusiform, surface rough. Vertex bearing a small subtriangular process, forming a distinct cocoon cutter at the centre. Labrum short, round, triangular. Antennae and forewing extend to posterior margin of A 4 (fourth abdominal segment). Galea reaching posterior margin of A 3. Prothoracic, mesothoracic, and metathoracic legs extended to the middle of A 3, middle of A 4, and anterior margin of A 5, respectively. Prothorax with one pair of projections at anterolateral corners of tergum. Spiracles conical, strongly elevated; each pair varies in length from A 2 to A 7; spiracles not visible on A 1 and partially closed on A 8. Two pairs of short setae symmetrically present on anterior 1 / 3 of mesothoracic tergum; a pair of short setae symmetrically present on anterior 1 / 3 of metathoracic tergum. One pair of setae on anterolateral corners of A 1 relatively less developed; a pair of setae adjacent to each spiracle from A 2 to A 7. Ninth abdominal segment with pair of short, round dorsal distal lobes. Ninth and tenth segments with 16 stout cremaster hooks. Proleg scars horizontal, symmetrical, strongly sclerotised, forming a ridge out of the ventral plate, with each pair present in the middle of A 5 and A 6.

Distribution.

Japan (Hokkaido, Honshu, Shikoku, Kyushu).

Host plant.

Carpesium divaricatum Sieb. & Zucc. ( Asteraceae ).

Biology.

Larvae mine inside the host leaves, causing a broad linear to blotch mine. Mature larvae mine into the host and weave cocoons under the epidermis of leaves near the petiole. Unlike typical Acrolepiinae cocoons, i. e. mesh-like cocoons consisting of one layer, these cocoons consist of two different layers. The outer layer is rough and made of thick silk, whereas the inner layer is smooth and made of fine silk. The pupal period took 14.5 days on average (n = 33) under laboratory conditions. Adults occur at least twice annually, or the adult period varies between locations because the Izu Peninsula’s population emerged in April, whereas Fukuoka’s population emerged from July to August. A few adults were collected during the day, resting on flowers of Eupatorium chinense L. var. simpliciforium Kitam. ( Asteraceae ).

Remarks.

This species was first reported as a leaf miner in Campanula punctata Lam. ( Campanulaceae ), with only one male specimen reared from the Izu Peninsula ( Suzuki et al. 2018; Suzuki T pers. comm.). In spring, when the larvae were mining the leaf, the host plant was difficult to identify because it had only a rosette; therefore, we visited the same locality again in early September 2022. By checking the flowers, we observed that the host plant was not Campanula punctata but Carpesium divaricatum ( Asteraceae ). Additionally, a few specimens collected by Hiroshi Kuroko at Mt. Hikosan in Fukuoka Prefecture were labelled to indicate that this species is a leaf miner of Carpesium divaricatum . Suzuki et al. (2018) reported that the host plant, Campanula punctata , was misidentified.

Etymology.

The specific name of Digitivalva bella sp. nov. is the female form of the Latin adjective bellus, “ beautiful, ” to describe the fascinating bright orange with silvery white stripes of the forewing, which can be differentiated from other species of the genus Digitivalva .

Figures

Figure 1. Adults of Digitivalva bella sp. nov. A. Male, holotype. B. Female, paratype. Scale bars: 2 mm.

Figure 2. Wing venation of Digitivalva bella sp. nov. A. Male, paratype, slide No. XZW- 8. B. Female, paratype, slide No. XZW- 5. fr: frenulum. Scale bars: 2 mm.

Figure 3. Male genitalia of Digitivalva bella sp. nov., slide No. XZG- 24 A. Whole genitalia except phallus, ventral view. B. Ditto, lateral view. C. Right valva, inner view. D. Phallus, lateral view. ta: tuba analis, vl: valva, anel: anellus, vin: vinculum. Scale bars: 0.4 mm (A, B), 0.3 mm (C, D).

Figure 4. Female genitalia of Digitivalva bella sp. nov., slide No. XZG- 29 A. Lateral view. B. Ventral view. pa: papillae analis, aa: apophysis anterioris, ap: apophysis posterioris, cb: corpus bursae, db: ductus bursae, ds: ductus seminalis, st: sterigma, ob: ostium bursae. Scale bars: 0.4 mm.

Figure 5. Pupa of Digitivalva bella sp. nov. from Tarai-misaki, Toji, Izu Peninsula, Japan. A. Ventral view. B. Lateral view. C. Dorsal view. at: antenna, fr: frons, fw: forewing, ga: galea, hw: hindwing, lb: labrum, lg 1: fore-leg, lg 2: mid-leg, lg 3: hind-leg, lp: labial palpus, pc: proleg scar, vx: vertex. Scale bar: 2 mm.

Figure 6. Habitat and hostplant: Carpesium divaricatum Sieb. & Zucc. (Asteraceae) of Digitivalva bella sp. nov. at Tarai-misaki, Toji, Izu Peninsula, Japan. A. Sampling site in April 2022. B. Ditto, in September 2022. C, D. The host plants with mine in April 2022. E. The blossomed host in September 2022. F. Cocoon buried under the petiole of the host.

Figure 7. The life history of Digitivalva bella sp. nov. at Tarai-misaki, Toji, Izu Peninsula, Japan. A. Last instar larva. B, C. Last instar larvae mining inside the host. D. Pupation site (arrow) inside the leaf. E. Cocoon with the pupa inside under the epidermis. F. Cut cocoon and pupal exuviae. G. Lateral, ventral, and dorsal views of pupal exuviae. H. Resting posture of an emerged adult.

Figure 8. Old specimens of Digitivalva bella sp. nov. A, B. The female adult from Dr. Yukata Arita’s collection (NSMT), with the labels attached to the specimen. C, D. The female adult from Dr. Hiroshi Kuroko’s collection (OPU), with the labels attached to the specimen.