Dercetina taiwana ( Chujo , 1938)

Lee, Chi-Feng & Bezdek, Jan, 2013, Revision of the genus Dercetina from Taiwan and their similar species, with description of a new species from Myanmar (Insecta, Chrysomelidae, Galerucinae), ZooKeys 323, pp. 1-33 : 16-19

Dercetina taiwana ( Chujo, 1938) stat. r.

Dercetis taiwana Chûjô, 1938: 140; Chûjô 1962: 145 (redescription); Gressitt and Kimoto 1963: 710 (as synonymy of Dercetina chinensis ).

Dercetis taiwana ab. melania Chûjô, 1938: 140; Gressitt and Kimoto 1963: 710 (confirmed as infraspecific variation of Dercetina chinensis )

Dercetis taiwana var. melania: Chûjô 1962: 146 (redescription).

Dercetis taiwana f. melania: Chûjô 1965: 95 (Taiwan).

Dercetina chinensis : Kimoto 1966: 33 (Taiwan); Kimoto 1969: 66 (Taiwan); Takizawa et al. 1995: 63 (Taiwan).

Dercetina flavocincta : Kimoto 1989a: 260 (Taiwan); Kimoto 1991: 17 (Taiwan).

Type series.

Dercetis taiwana : Lecotype ♂, here designated, labeled: "Formosa Shinchiku (= Hsinchu), -18. VII 1-30. J. Sonan / COType (circular label with yellow letters and border) / Dercetis taiwana CHÛJÔ DET. M. CHUJO / 1916" (TARI). Paralectotypes: 3♀♀: "Urai (= Wulai, in Taipei county) FORMOSA 28.III.1932 COL. M. CHUJO / COType (circular label with yellow letters and border) / Dercetis taiwana CHÛJÔ DET. M. CHUJO / 2379, 2380, 2384 (respectively)" (TARI); 2♀♀: "Taiheizan (= Taipingshan, in Ilan county) FORMOSA Jul 1930 S. Minowa / COType (circular label with yellow letters and border) / Dercetis taiwana CHÛJÔ DET. M. CHUJO / 2162 or 2385" (TARI); 1♀: "Formosa Arisan (= Alisan, in Chiayi county), 1918 X 2-23. J. Sonan COType (circular label with yellow letters and border) / Dercetis taiwana CHÛJÔ DET. M. CHUJO / 2159" (TARI); 1♂: "Formosa Y. Miwa / Rimogan (= Fushan, in Taipei county) 22.7.1929 (on the back) / COType (circular label with yellow letters and border) / Dercetis taiwana CHÛJÔ DET. M. CHUJO / 2160" (TARI); 1♀: "Formosa Y. Miwa / Kobayashi, 25.7.1929 / Syntypus (red label) / Dercetis taiwana CHÛJÔ DET. M. CHUJO / DEI Müncheberg Col - 03095" (SDEI); 1♀: "Paroe (Form.) H. Sauter IX.1912 / Syntypus (red label) / Dercetis taiwana CHÛJÔ DET. M. CHUJO / DEI Müncheberg Col - 03096" (SDEI); 1♀: "Taihorin (= Talin, in Chiayi county) Formosa H. Sauter, 1911 / 7.VII. / Syntypus (red label) / Dercetis taiwana CHÛJÔ DET. M. CHUJO / DEI Müncheberg Col - 03097" (SDEI); 1♀: "Formosa Y. Miwa / Hsuanyan (in Japanese) 23.7.1929 / COType (circular label with yellow letters and border) / Dercetis taiwana CHÛJÔ DET. M. CHUJO / 2161" (TARI).

Dercetis taiwana ab. melania: Syntypes: 1♂, 1♀: "Urai (= Wulai, in Taipei county) FORMOSA 28.III.1932 COL. M. CHUJO / COType (circular label with yellow letters and border) / Dercetis taiwana ab. melania CHÛJÔ DET. M. CHUJO / 2374 or 2375" (TARI); 2♀♀: "Urai (= Wulai, in Taipei county) FORMOSA 28.III.1932 COL. M. CHUJO / Syntypus (red label) / Dercetis taiwana ab. melania CHÛJÔ DET. M. CHUJO / DEI Müncheberg Col - 03098 and 03099" (SDEI); 1♂, 1♀: "Formosa Shinchiku (= Hsinchu), -18. VII 1-30. J. Sonan / COType (circular label with yellow letters and border) / Dercetis taiwana ab. melania CHÛJÔ DET. M. CHUJO / 2163 or 1923" (TARI); 1♀: "Formosa Y. Miwa / Urai (= Wulai in Taipei county) 20.7.1929 (on the back) / COType (circular label with yellow letters and border) / Dercetis taiwana ab. melania CHÛJÔ DET. M. CHUJO / 1915" (TARI); 1♂: "Formosa Y. Miwa / Hsitsun (in Chinensis) 24.7.1929 (on the back) / COType (circular label with yellow letters and border) / Dercetis taiwana ab. melania CHÛJÔ DET. M. CHUJO / 2164".

Material examined.

CHINA: 1♂, 1♀, Guangdong, Tsha-jiu-san, V.-VI.1912, leg. S. V. Mell (KMNH); 1♂, Hubei, Lichuan, Suisapa, 23.VIII.1948, leg. J. L. Gressitt (KMNH); 1♂, Hubei, Lichuan, Lianghokeu, 1.IX.1948, leg. Gressitt & Djou (KMNH); TAIWAN: 1♀, Hsinchu, Chienshih, 26.VII.2008, leg. H.-J. Chen (TARI); 1♂, same locality, 26.IX.2009, leg. H.-J. Chen (TARI); 1♂, 1♀, Hsinchu, Lupi, 24.VI.2008, leg. H. Lee (TARI); 1♀, Hsinchu, Peitelaman, 26.VI.2008, leg. S.-F. Yu (TARI); 3♂♂, 5♀♀, Hsinchu, Talu trail, 22.VIII.2009, leg. Y.-L. Lin (TARI); 1♀, same locality, 19.VI.2010, leg. Y.-L. Lin (TARI); 2♂♂, Hsinchu, Wufeng, 12.VII.2008, leg. H.-J. Chen (TARI); 1♀, same locality, 29.IX.2009, leg. Y.-L. Lin (TARI); 1♂, 2♀♀, Hsinchu, Yulao, 3.IV.2011, leg. M.-H. Tsou (TARI); 2♀♀, Ilan, Fushan Botanical Park, 1.IV.2008, leg. H.-J. Chen (TARI); 4♂♂, 5♀♀, same locality, 1.IV.2008, leg. M.-H. Tsou (TARI); 1♂, same locality, 2.IV.2008, leg. H.-J. Chen (TARI); 2♂♂, same locality, 20.III.2009, leg. C.-F. Lee (TARI); 1♂, 1♀, Ilan, Mingchi, 17.III.2007, leg. M.-H. Tsou (TARI); 2♂♂, 7♀♀, same locality, 29.VII.2007, leg. M.-H. Tsou (TARI); 3♂♂, 2♀♀, same locality, 27.IV.2008, leg. S.-F. Yu (TARI); 2♀♀, same locality, 25.V.2008, leg. M.-H. Tsou (TARI); 1♀, Ilan, Suchi trail, 19.V.1910, leg. H.-J. Chen (TARI); 1♀, Ilan, Taipingshan, 3.VI.2007, leg. S.-F. Yu (TARI); 1♂. 5♀♀, Ilan, Tsuifenghu, 3.VII.2010, leg. M.-H. Tsou (TARI); 1♀, Taichung, Yuantsuishan, 16.VII.2010, leg. J.-C. Chen (TARI); 2♀♀, Taipei, Chutzuhu, 16.IX.2007, leg. S.-F. Yu (TARI); 3♂♂, same locality, 15.VI.2008, leg. M.-H. Tsou (TARI); 1♂, 1♀, Taipei, Erhkoshan, 26.XI.2006, leg. M.-H. Tsou (TARI); 1♂, 1♀, Taipei, Fengkueitsui, 29.VI.2007, leg. S.-F. Yu (TARI); 1♀, Taipei, Fushan, 5.IV.2007, leg. S.-F. Yu (TARI); 1♂, 2♀♀, Taipei, Hsiaoyuken, 29.III.2008, leg. M.-H. Tsou (TARI); 1♂, 2♀♀, Taipei, Lengshuiken, 22.VI.2008, leg. S.-F. Yu (TARI); 3♂♂, 2♀♀, Taipei, Menghu, 27.IX.2007, leg. S.-F. Yu (TARI); 3♂♂, 7♀♀, Taipei, Pinglin, 29.III.2008, leg. M.-H. Tsou (TARI); 1♂, 3♀♀, Taipei, Wulai, 10.VII.2007, leg. H.-T. Cheng (TARI); 4♀♀, same locality, 27.IX.2006, leg. H.-J. Chen (TARI); 2♂♂, 3♀♀, same locality, 22.X.2006, leg. S.-F. Yu (TARI); 1♂, 1♀, same locality, 26.X.2006, leg. S.-F. Yu (TARI); 2♀♀, same locality, 19.VI.2007, leg. M.-H. Tsou (TARI); 2♀♀, 30.IX.2007, leg. M.-H. Tsou (TARI); 1♀, Taipei, Yangmingshan, 3.III.1998, leg. C.-F. Lee (TARI); 1♂, same locality, 15.III.1998, leg. C.-F. Lee (TARI); 1♂, 1♀, same locality, 29.VIII.2006, leg. H.-J. Chen (TARI); 1♀, same locality, 15.IV.2007, leg. M.-H. Tsou (TARI); 1♀, same locality, 19.V.2007, leg. M.-H. Tsou (TARI); 2♀♀, same locality, 1.VI.2007, leg. S.-F. Yu (TARI); 3♂♂, 1♀, same locality, 23.VI.2007, leg. S.-F. Yu (TARI); 1♂, Taipei, Yingtzuling, 24.VII.2010, leg. Y.-L. Lin (TARI); 2♀♀, same locality, 25.IX.2010, leg. Y.-L. Lin (TARI); 1♀, Taoyuan, Hsiaowulai, 29.IX.2009, leg. M.-H. Tsou (TARI); 1♂, same locality, 1.VI.2010, leg. S.-F. Yu (TARI); 1♂, Taoyuan, Tsuehwunao, 10.IV.2011, leg. M.-H. Tsou (TARI); 2♂♂, Taoyuan, Mamei, 3.IV.2011, leg. M.-H. Tsou (TARI); 6♂♂, 13♀♀, Taoyuan, Paling, 8.XI.2009, leg. M.-H. Tsou (TARI); 1♂, same locality, 11.IV.2010, leg. M.-H. Tsou (TARI); 1♂, 1♀, Taoyuan, Tungyanshan, 14.VII.2008, leg. H. Lee (TARI); 1♀, same locality, 17.IV.2009, leg. H. Lee (TARI); 3♂♂, same locality, 10.V.2009, leg. H. Lee (TARI); 1♀, same locality, 16.VI.2009, S.-F. Yu (TARI);

Diagnosis.

Dercetina taiwana is similar to Dercetina chinensis and Dercetina barclayi sp. n. in the absence of lateral fovea on the pronotum and antennomere III slightly longer than IV. Dercetina taiwana and Dercetina chinensis are separated from Dercetina barclayi sp. n. by its sexually dimorphic antennae. Both species have their distinct color patterns in most individuals: the bluish black elytra with white transverse band at middle in Dercetina taiwana ; the yellowish brown elytra with or without longitudinal black bands long suture and lateral margins in Dercetina chinensis . Although some individual specimens of both species share the same color pattern, Dercetina taiwana differs from Dercetina chinensis by a more oval elytra (1.4 times longer than wide in contrast with 1.6 times longer than wide in Dercetina chinensis ).

Redescription.

Color (Figs 46-47) bluish black, head (except eyes and antennae), prothorax, coxae, and tibiae yellowish brown; elytra with one transverse white stripe at basal 1/3. Head smooth and impunctate. Pronotum transverse, 1.9-2.0 times wider than long, evenly convex on disc and lacking fovea or punctured depression, disc with scattered fine punctures; lateral margin rounded, anterior margin concave, posterior margin slightly rounded. Elytra more or less widened posteriorly, apex convergently rounded, 1.4 times longer than wide, disc with punctures in part arranged in longitudinal rows, epipleurae smooth and impunctate.

Male. Length 4.0-4.5 mm, width 2.2-2.5 mm. Ratio of length of antennomeres III to XI about 1.0: 1.3: 1.3: 1.3: 1.3: 1.2: 1.2: 1.1: 1.3; ratio of length to width of antennomeres III to XI about 2.5: 2.9: 3.0: 3.2: 3.3: 3.3: 3.6: 3.6: 4.5 (Fig. 56). Penis (Fig. 58) extremely slender, about 8.4 times longer than wide, parallel-sided, basally widened, apex narrowly rounded; tectum membranous, with scatted stout setae; weakly curved in lateral view (Fig. 59); endophallic sclerite elongate, about 0.4 times as long as penis, base and apex concave and membranous, with a dorsal sclerite connected at basal 1/4, almost reaching base, with a row of short setae along lateral margin at apical 1/4; in lateral view almost straight.

Female. Length 5.2-5.7 mm, width 3.0-3.3 mm. Antenna 11-segmented, filiform (Fig. 57), comparatively narrower than in male, ratio of length of antennomeres III to XI about 1.0: 1.3: 1.3: 1.3: 1.3: 1.3: 1.3: 1.2: 1.5; ratio of length to width of antennomeres III to XI about 2.9: 3.1: 3.3: 3.5: 3.6: 3.5: 3.9: 4.0: 5.4. Sternite VIII (Fig. 60) weakly sclerotized subapically, apex truncate, setae along lateral and apical margin, spiculum long. Spermathecal receptaculum (Fig. 61) swollen; pump narrow and strongly curved, apex narrowly rounded; spermathecal duct short, deeply projecting into receptaculum. Gonocoxae (Fig. 62) narrowly connected in middle, about 4.6 times longer than wide, straight, with one short setae at apical 1/3 and nine setae at apex.

Color variation. A number of individuals have transverse white strip on elytra reduced at various degrees, or even totally absent (Fig. 48); some have the vertex, clypeus, and labrum darkened; a few individuals have pronotum darkened.

Host plants.

Betulaceae : Alnus formosana (Burkill ex Forbes & Hemsl.) Makin; Compositae : Eupatorium formosanum Hayata; Fagaceae : Quercus variabilis Bl.; Lauraceae : Cinnamomum camphora (L.) Presl. and Litsea cubeba (Lour.) Persoon; Lythraceae : Lagerstroemia subcostata Koehne; Moraceae : Humulus scandens (Lour.) Merr.; Rosaceae : Prunus campanulata Maxim.; Rutaceae : Tetradium glabrifolium (Champ. ex Benth.) T. Hartley; Stachyuraceae : Stachyurus himalaicus Hook. f. & Thomson ex Benth.; Ulmaceae : Trema orientalis (L.) Bl.

Distribution.

China (Guandung, Hubei) and Taiwan. Dercetina taiwana is widespread in northern Taiwan from lowlands to high mountains (above 2000 m) (Fig. 15). This species is rather abundant.