Thiotricha gemmulans Meyrick, 1931

Kyaw, Khine Mon Mon, Ueda, Tatsuya, Yagi, Sadahisa, Okamoto, Tomoko, Wang, Min & Hirowatari, Toshiya, 2021, A Taxonomic study of two species of Thiotricha Meyrick (Lepidoptera: Gelechiidae), from southwestern Japan, with notes on the biology of their immature stages, Zootaxa 4980 (2), pp. 331-354 : 338-342

Thiotricha gemmulans Meyrick, 1931

[Japanese name: Kankonoki-kibaga]

Figs 2 , 3 , 4 , 5 , 6B , 8 , 10 , 12 , 13D–F , 15 .

Thiotricha gemmulans Meyrick, 1931: 63 . TL: Bombay, India. TD: NHMUK.

Thiotricha acrophantis Meyrick, 1936: 45 . TL: Formosa, Taiwan. TD: NHMUK. Syn. Nov.

Material examined. JAPAN: Ryukyus. Kagoshima Pref. : 2♀, Akusekijima Is., Toshima Town , 14 vii 2012, Takeshi Terada leg ( KGU) ; 1♂, 2#, same locality and collector, 19 vii 2012 ( KGU) ; 1♂, 2♀, same locality and collector, 20 vii 2012 ( KGU) ; 2♂, Takao, Nakano-shima Is. , Tokara Islands., N: 29°50’25.68, E: 129°52’38.29, 227 m, 15 ix 2018, K. Sakagami leg. (Light) ( ELKU) ; 1♀, Nanatsuyama, Nakano-shima Is., Tokara Islands , 227m, N: 29°50’23.89, E: 129°53’26.72, 134 m, 13.ix.2018, K. Sakagami leg. (Light) ( ELKU) ; 2♂, 3♀, Amami-oshima , 19–20 vi 2015 (larva), 3–27 vii 2015 em., T . Okamoto leg., gen slide no. KM –8 (♂), 45 (♂), 112 (♀), Host Plant: Glochidion zeylanicum (ELKU) ; 1♀, Sumiyo-cho , Amami-oshima Is., 10 vii 2016, S. Sameshima & T . Terada leg., gen slide no. KM –123 ( KGU); 1♂, 2♀, Tokunoshima, San Tokuno-shima , 9 vii 2016 LT 230m, S. Yagi leg., gen slide no. KM – 113 (♀) ( ELKU) ; 2♀, same locality and collector, 12 vii 2016 LT 320m, gen slide no. KM –127, 136 ( ELKU); 1♀, Tokunoshima, Todoroki , 11 vii 2016 LT 140m, S. Yagi leg., gen slide no. KM – 16 ( ELKU); Okinawa Pref. : 1♀, Aha, Kunigami-vill , 26’’ 43’’ 30’’N 128’’ 16’’00’’E, 6 vi 2015 (Light Trap), T . Terada leg., EOMM 08866 ( OMM) ; 2♂, Mt. Terukubi 330m, Benoki Kunigami-son , 4–5 viii 2015 LT , S. Yagi leg., gen slide no. KM –10,138 ( ELKU); 3♀, same locality and collector, 4 viii 2015, gen slide no. KM –114, 124 ( ELKU); 1♀, Mt. Yonaha, Okuma Kunigami , 8 viii 2016 LT 250m, N:26.7274, E:128:2098, S. Yagi leg., gen slide no. KM –54 ( ELKU); 6♂, 2♀, Okuni-rindo, Hentona, Okinawa-jima , 8 viii 2017 (larva), 13–27 viii 2017 em., T . Hirowatari, S. Yagi & K.M.M. Kyaw leg., gen slide no. KM –90 (♂), 91 (♂), 103 (♂), Host Plant: Glochidion zeylanicum (ELKU) ; 1♂, 1♀, same locality, collector and host plant, 9 viii 2017 (larva), 25–28 viii 2017 em., gen slide no. KM – 139 (♀) ( ELKU) ; 1♂, Mt. Tamatsuji , 9 viii 2017 larva, 30 viii 2017 em., T . Hirowatari , S. Yagi. K. M. M. Kyaw leg., Host Plant: G. zeylanicum (ELKU) ; 7♂, 4♀, Shinrin-Koen, Kunigami-son , 7 viii 2016 (larva), 14–25 viii 2016 em., S. Yagi leg., gen slide no. KM –9 (♂), 53(♂), 107(♂), 122(♀), SY–209 (♂), 216 (♀), Host Plant: G. zeylanicum (ELKU) ; 1♀, Mt. Otoha 250m, Jana Nakijin-son , 5 viii 2015 (larva), 8 viii 2015 em., S. Yagi leg., gen slide no. KM – 61, Host Plant : G. zeylanicaum (ELKU) ; 1♀, Mt. Katsuu-dake, Nago City , 26° 27’ 51” N 127’’ 56’’ 20’’ E, 1 x 2015 (Light Trap), T . Terada leg., EOMM08865 , gen slide no. EOMM08865 ( OMM) ; 2♂, Ishikawa-rindo, Onna-vill , 26’’ 25’ 23’’ N 127’’47’17’’E, 18 v 2015, 18 viii 2015 (Light Trap), T . Terada leg, EOMM08863 , 08864 ( OMM) ; 1♀, Nagura, Ishigaki-jima , 1 v 1978, S. Moriuti leg. ( OPU) ; 2♀, Mt. Yarabu, Sakieda , 5 vii 2017 LT , S. Yagi leg. ( ELKU); 1♀, Mt. Tedou, Uehara , N24.381, E123.819, 100–150 m, 8 vii 2017 LT , S. Yagi leg. ( ELKU); 2♂, 1♀, Mt. Tedou , Uehara, 8 vii 2017 LT , Khine Mon , T . Hirowatari & S. Yagi leg. ( ELKU); 1♂, Shirahama, Iriomote-jima , 13 vii 2001 (at light), T . Yamauchi leg. ( OPU); 1♂, same locality, 8 v 2012 LT, T. Hirowatari, S. Kobayashi, K. Nakatsuka, T. Yoshida leg. ( OPU); 1♂, 1♀, Urabudake, Yonaguni-jima , 29, 31 vii 1994, T . Yamauchi ( OPU) ; TAIWAN: 3♂, 1♀, Neiwen, Shizi, Pingtung, Taiwan , 12 v 2017 LT , S. Yagi leg., gen slide no. KM – 84 (♂), 80 (♀) ( SCAU) ; CHINA: 1♂ [Guangdong Prov.] Shimentai Nature Reserve, Yingde , 19 ix 2018 LT , M. Wang, G-H Huang & S. Yagi ( SCAU) ; THAILAND: 1♀, Chanthabury, Khao Soi Dao (ca. 400 m), 7–8 x 1985, Kuroko, Moriuti, Saito & Arita ( OPU) .

Diagnosis. Thiotricha gemmulans Meyrick, 1931 is similar to T. albicephalata (Walia 2005) , T. margarodes Meyrick, 1904 , and T. pteropis Meyrick, 1908 . The wing markings of T. gemmulans is similar to them by sharing the wedge-shaped dark gray spot edged with fuscous line and orange scales beneath apical spot but it can be distinguished from them by the oblique blackish line from 3/4 costa, the small inverted triangular brownish gray mark before apex, with three brownish gay lines on cilia. In addition, the male genitalia of T. gemmulans are similar to T. albicephalata by sharing the U-like uncus, sickled shaped gnathos, oval shaped anellus lobe, the shape of phallus is basally broad and narrowed distally in both but slightly sinuate at about half length in T. gemmulans . In the female genitalia, the shape of signum of T. gemmulans is flattened with spine like median process and that of T. albicephalata is rod-like.

Redescription. Adult. Male ( Fig. 4A ). Forewing length 2.5–2.9 mm (n=11). Wing expanse 5.3–6.1 mm (n=11). Head smooth, pale yellow. Scape rather elongate without pecten and pale ocher, sparsely speckled with brownish scales on dorsal surface; flagellum filiform; each flagellomere grayish-white on dorsal surface beyond middle, brownish gray on dorsal and ventral surface apically, with long cilia on ventral surface. Labial palpus ( Fig. 5A ) pale ocher, suffused with dark-brown scale medially on outer surface; first palpomere as long as second; second thickened, a bundle of long hair pencil arising from base, appressed on dorsal surface, extending to sub-apex of the third segment; third as long as 1.5X of second, recurved and moderately acute at apex. Haustellum pale yellow. Mesothorax pale ocher; tegula pale ocher intermixed with black scales along anterior margin. Legs pale ocher; forefemur, tibia, and tarsus pale ocher on inner surface and suffused; outer surface dark gray; midleg pale ocher on inner surface, mid-tibia suffused; outer surface dark gray; all tarsomeres 1–4 on outer surface, ringed with white apically; tarsomere 5 entirely grayish-black; hind femur and tibia pale ocher on inner surface, suffused with grayish black on outer surface, covered with a row of shortened, stiff, pale ocher bristles dorsally and ventrally; all tarsomeres except last with dark gray ringed with white apically, last tarsomere dark gray. Forewing narrow; R4 stalked with M1; R5 absent (or coincident with R4); CuA1 and CuA2 separated, retinaculum represented by a hook arising from Sc and a series of curved liner scales along R; forewing ground color pale yellow, costa shallowly concave, apex attennuate, termen extremely oblique; a wedge-shaped dark gray spot partially edged with fuscous line, broadest anteriorly, and extending along the lower half of termen to sub-apex, connecting with an oblique blackish line at 3/4, extending to near sub-apex; small inverted triangular brownish gray mark before apex; a round blackish apical spot at apex; cilia brownish white, orange colored cilia beneath apical spot, rounded apex with three short brownish gray lined cilia, whitish brown cilia throughout the base. Hindwing, pale gray, with a small apical spot; fringe long at base, shortening apically.

Female ( Fig. 4B ). Forewing length 2.6–3.3 mm (n=15). Wing expanse 5.5–6.7 mm (n=15). Similar to males, but some differences in the following characters. In forewing, retinaculum represented by a hook arising from Sc and two rows of apical curved liner scales along Sc and Radius. Labial palpus whitish gray to whitish brown ( Fig. 5B ). First palpomere short, pale yellow, with brown scales medially on the dorsal surface; second pale yellow, as long as 2 times the first, suffused with brown scales dorsally; third nearly the same length as the second, brownish gray entirely, upturned and slightly acute apically. Forewings with two rows of apical curved liner scales along Sc and R in females.

Abdomen ( Fig. 4I, J ). Terga and sterna 1–7 unmodified as in Fig. 4I . Tergum-8 concave with sclerotized margin; sternum-8 slightly broadened at the base and then tapered apically, delineated with rounded surface and bifid posteriorly as in Fig. 4I, J .

Male genitalia ( Fig. 4C, D ). Uncus broad, elongate, narrowly-rounded, setose lobes, with a few short and stout spines at lateral corner on both sides. Tegumen approximately 2/3, nearly 2.5X length of uncus. Gnathos long, sickle-shaped, apically pointed. Anellus lobe oval-shaped basally, and rather long and fine setae arising on its surface, bearing a slightly long and moderately sclerotized spine apically, recurved inwardly. Valva uniformly elongate, finely setose, and parallel-sided from base to apex, apex narrowly-rounded. Vinculum slightly narrowed, median process with long and short setae on medially. Saccus triangular. Phallus with a broadened basal half, narrowed distally, slightly sinuate at about half length.

Female genitalia ( Fig. 4E–H ). Papillae anales lobate, forming a triangular-shaped, ventral surface interspersed with long and short setae. Apophyses anteriores and apophyses posteriores almost equal in length. Lamella antevaginalis narrow, and U-shaped. Ostium near the anterior margin of the 8 th sternite. Ductus bursae slightly narrowed on posterior 1/3, gradually broadened anteriorly. Ductus seminalis arising from posterior end of ductus bursae ( Fig. 4F ). Corpus bursae ovoid, as long as ductus bursae; signum on posterior end, flattened, with spine-like median process.

Distribution. Japan (Ryukyus), China (Guangdong), Taiwan (Pintaung, Tainan), Thailand (Chanthaburi), India ( Bombay).

Biology ( Fig. 8 ) Larvae construct a portable case from the flower buds of its host plant. At first, the larva penetrates one flower bud and then makes a small hole to enter inside ( Fig. 8D ); lives and feeds within it ( Fig. 8E ). After consuming the inside of the flower bud, it moves to another flower bud and penetrates again with hollowed bud as its case. Larvae repeat this process until the last instar. Pupation occurs within stacked cases of three or four flower buds. The number of stacked flower buds appears to depend on the size of the flower buds. Larvae use to attach the case to the top of the flower bud to complete its development ( Fig. 8G ). When larvae are ready to pupate, they usually attach their case to the underside of a leaf ( Fig. 8H ) or sometimes to a flower bud.

Host Plant. Glochidion zeylanicum var. zeylanicum (Gaertn.) A. Juss , G. zeylanicum var. lanceolantum (Hayata) M.J.Deng & J.C.Wang (Phyllanthaceae)

Larva ( Fig. 8I ). Length 2.5–3.5 mm (n=6). Head subglobular. Body pale yellow in early instars and yellowishbrown in later instars. Prothoracic shield yellowish-brown, with dark brown on caudal margin. Thoracic leg short, pale yellowish. Pinaculum more or less rounded, dark brown on T1–T3 and A1, A2, A8, and A9; paler on remaining abdominal segments. Anal shield heavily sclerotized, yellowish-brown ( Fig. 10C ). Anal fork deeply emarginated mesially, forming two lateral lobes ( Fig. 10D ). Anal prolegs with many minute spines on dorsal surface. Crochets in a circle, uniordinal, 11–16 in number on planta, 9–10 on anal planta.

Chaetotaxy ( Fig. 10 ) Head ( Fig. 10A, B ): epicranial suture shorter than frontoclypeus, AF1 about equal in length with AF2; C2 slightly longer than C1; P1 dorsolateral to AF1 about 5X longer than P2; P2 dorsolateral to AF2 and P1; MD1-MD3 setae forming nearly in a line at the posterior margin of head capsule; mouthparts semihyponathous; genal area with six stemmata, forming a semicirclar pattern; A1 dorsoanterior to stemma-3, slightly shorter than A3; A2 lateral to A1, and shorter than A1 and A3; L1 dorsoposterior to stemma-1; distance between L1 and A3 slightly longer than distance between A3 and A2; S1 below stemma-3, short as A2; S2 longer than S1 and S3, near the opening of the stemmatal semicircle; S3 about 1/2 shorter than S1, and ventroposterior to stemma-6; SS1 near mandibular condyle, same length as SS2; SS2 between SS1 and SS3; SS3 about 3X longer than SS1 and SS2; MGa present, close to MG1.

Thorax: Prothorax ( Fig. 10E ). Shield with SD1 ventrolateral to XD1 and XD2, along anterior margin; XD2 less than twice the distance from XD1 than from SD1; XD1 and XD2 about equal in lengths; SD2 and D1 about equal in lengths, both setae less than about 2½–3X length of SD1 and D2; SD2 slightly farther from XD2 than to SD1; L-group trisetose on same pinaculum, anteroventral to spiracle; L1 longest; L2 and L3 short, about equal in lengths; SV-group bisetose, on same pinaculum, SV1 about 2–2½X longer than SV2; MV1 absent; MV2 approximate to anterolateral coxal margin; V1 approximate to mesoposterior coxal margin.

Meso and metathorax ( Fig. 10E ). with D1, D2, SD1 and SD2 on same pinaculum; on separate pinacula on T3 (not shown); D2 about 3½–4X length of D1; SD1 about 3½–4X length of SD2; MD1 anterolateral to D2; MSD 1 in line with MSD2 and anterior to SD2, MSD2 anterior to SD1; L1 about 2½–3X length of L2, both on a same pinaculum, slightly anterior to D-SD group pinaculum; L3 slightly longer than L2, in vertical line with SV1; MV1, MV2 and MV3 anterior to coxa; with MV2 approximate to anterolateral coxal margin, and MV3 slightly above V1.

Abdomen: ( Fig. 10E ). A1–A2 with D2 about 3½–4X longer than D1; D1 dorsoanterior to D2; MD1 slightly ventral to D1 and D2; SD1 about equal in length with D1; SD2 minute, anteroventral to SD1 and on different pinaculum; SD1 above spiracle; SD2 anteroventral to SD1; L-group trisetose; L1 and L2 on same pinaculum, in vertical line with SD-group and below spiracle; L1 about 2–3X longer than L2 and L3; L3 slightly longer than L2; SV-group bisetose on A1, SV1 about 2½–3X longer than SV2 and on different pinaculum on A1; SV-group trisetose on A2, with SV1 and SV3 on same pinaculum, SV2 on separate pinaculum (not shown); MV3 dorsoanterior to V1; A3–A6 as above A2, except each segment bearing a pair of protuberant prolegs; planta bearing uniordinal, uniserial crochets, in a circle (not shown); A7 as above except with SV-group bisetose on same pinaculum, and MV3 dorsoanterior to V-group pinaculum, and V1 ventral to SV pinaculum; A8 as above except with SD1 about equal in length with D2; D 2 in vertical line with SD1, minute SD2 on same pinaculum as SD1, SD-group pinaculum slightly anterior to spiracle, spiracle slightly dorsal to all spiracles on A1–A7; L1 about 3½–4X length of L2; L1 and L 2 in vertical line with D2 and SD1; L3 anteroventral to L1 and L2; SV-group unisetose; A9 as above except with D1 ventral to D2 and on same pinaculum; MD 1 in horizontal line between D1 and D2; SD1 absent; L-group bisetose on same pinaculum, L1 about 3½–4X length of L2; SV1 and V1 on separate pinacula.

Pupa ( Figs. 12 , 13D–F , 15 ). Length 2.3–3.5 mm (n=8). Yellowish-brown, cylindrical. Head rounded, with many minute granular projections. Vertex with many minute spines. Prothorax with a pair of small triangular projections on dorsolateral corners of tergite. Antennae extending beyond posterior end of A5. Forewings extending to near posterior margin of A5. Maxilla (galea) basally broad, gradually narrowing and extending to near posterior end of A4. Prothoracic legs extending to slightly beyond anterior margin of A3; mesothoracic legs extending to middle of A4; metathoracic legs extending to slightly beyond anterior margin of A6. Proleg scars indistinct.A7 with a transverse row of tergal spinules on anterior margin directed posteriorly and with a transverse row of minute spinules on caudal margin. Sternite A7 with a pair of oval pads equipped with a row of spines directed anteriorly. A10 with a pair of triangular projections on posterolateral, apically with three pairs of hooked setae on ventral surfaces of A9 and A10, no true cremaster present.

Remarks. This species was originally described by Meyrick (1931) from India, and here it is newly recorded from Japan, China, and Thailand. The wing markings and male genitalia are congruent with those of T. gemmulans Meyrick, 1931 , as shown by Clarke (1969). Moreover, its wing markings are also similar to those of T. acrophantis Meyrick, 1936 , which was originally described from Taiwan. However, examination of the genitalia of T. acrophantis was not available because it was described based on a single female specimen without an abdomen. Until now, there has been no study after that of Clarke, and the species has been regarded as separate following Meyrick. In the present study, we examined specimens collected in Taiwan, whose wing markings are identical to those of T. acrophantis shown by Clarke, and confirmed that their male genitalia are identical with those of T. gemmulans . Therefore, we conclude that T. acrophantis is a junior synonym of T. gemmulans .

Figures

FIGURE 2. Male genitalia. Thiotricha gemmulans. Scale bar: 0.20 mm.

FIGURE 3. Female genitalia. Thiotricha gemmulans. Sclae bar: 0.40 mm.

FIGURE 4. Adults of Thiotricha gemmulans Meyrick, 1936. A, Male; B, Female; C, Male genitalia except phallus, gen slide no. KM–107; D, Phallus; E, Female genitalia, gen slide no. KM–127; F, Close up of ductus seminalis, gen slide no. KM–445; G, H Close up of signum, gen slide no. KM–127, 136; I, Abdominal pelt, gen slide no. KM–107; J, Close up of sternum 8, gen slide no. KM–107. Scale bars: 4.0 mm (A, B), 0.40 mm (C, D, E, I, J), 0.20 mm (F), 0.10 mm (G, H).

FIGURE 5. Labial palps of Thiotricha gemmulans Meyrick, 1936. A, Male; B, Female. Scale bar: 0.40 mm.

FIGURE 6. Wing venation. A, Thiotricha lumnitzeriella sp.nov. (Paratype, male); B, T. gemmulans Meyrick, 1931 (Male). Scale bars: 0.40 mm.

FIGURE 8. Thiotricha gemmulans Meyrick, 1931 and its host plant. A, Host plant: Glochidion zeylanicum var. zeylanicum (Phyllanthaceae); B, Infested flower buds; C, Larva penetrating the flower bud; D, Flower bud with hole made by larva; E, Protruding larva from the flower bud; F, Larva carrying the portable case; G, Portable case attached to the top of flower bud; H, Portable case attached to the lower surface of leaf; I, Larva; J, Pupa; K, Pupal exuviae left by an emerged adult; L, Resting adult.

FIGURE 10. Chaetotaxy of Thiotricha gemmulans Meyrick, 1931. A, Head, frontal view; B, Ditto, lateral view; C, Anal shield; D, Anal fork; E, Prothorax, mesothorax, and abdominal segments 1, 6–9. Scale bars: 0.10 mm.

FIGURE 12. Pupa of T. gemmulans Meyrick, 1931. A, Ventral view; B, Lateral view; C, Dorsal view.

FIGURE 13. Pupa of Thiotricha spp. A–C, T. lumnitzeriella sp. nov.; D–F, T. gemmulans Meyrick, 1931 A, D, Dorsal view; B, E, Ventral view; C, F, Lateral view. Scale bars: 0.40 mm.

FIGURE 15. Pupa of Thiotricha gemmulans Meyrick, 1931. A, Head and thorax, dorsal view. Arrow indicates many minute granular projections on vertex; B, Abdomen, ventral view. Arrow indicates an oval pad equipped with a row of spines and A10 with triangular projections; C, A7, dorsal view. Arrow indicates a transverse row of tergal spinules on both anterior and caudal margins; D, A7, lateral view. Arrow indicates an oval pad equipped with a row of spines and rows of tergal spines. Scale bar: 0.40 mm.