Monolepta mandibularis Chûjô, 1962

Lee, Chi-Feng, Tian, Pei-Ling & Staines, Charles L., 2010, Monolepta meihuai, a New Species from Taiwan, with Redescription of Its Sibling Species Monolepta mandibularis Chûjô, 1962 (Coleoptera: Chrysomelidae: Galerucinae), The Coleopterists Bulletin 64 (4), pp. 303-311 : 304-306

Monolepta mandibularis Chûjô, 1962

Monolepta mandibularis Chûjô, 1962: 120 ; Kimoto (1969: 50); Kimoto (1989: 256).

Diagnosis. Monolepta mandibularis is similar to Monolepta bicavipennis Chen , with the yellowish brown or reddish elytra and presence of deep, broad post-median impression on the pronotum, but differs by the uniform elytra of both sexes (in contrast to the deep excavation on the elytra in males of M. bicavipennis ).

Redescription. Length: Males 5.0– 5.7 mm (mean = 5.3 mm; n = 6); females 5.1–5.9 mm (mean = 5.5 mm; n = 6). Color ( Figs. 1, 2 ): Dark brown or blackish brown; antenna black; elytra brown or yellowish brown; pronotum sometimes with same color as elytra. Antenna: Long ( Fig. 11 ), about 0.8X length of body, antennomeres IV-X about 3.9 times longer than broad at apex; length ratio of antennomeres II to III 0.81–0.97 (mean = 0.88); length ratio of antennomeres III to IV 0.41– 0.46 (mean = 0.44) ( Fig. 9 ) in males, 0.50–0.58 (mean = 0.54) in females. Thorax: Pronotal length to width 0.75–0.83 (mean = 0.78); maximal width of elytra to length of elytra 0.59–0.63 (mean = 0.61); length of basi-metatarsus to metatibia 0.39– 0.47 (mean = 0.43). Abdomen: Sternites with dense long hairs. Male genitalia: Median lobe broad ( Figs. 7–9 ), sub-parallel; apex slightly emarginated; ventral surface weakly sclerotized from apex to middle; tectum wide and short, about 0.5X as long as median lobe; spiculae of endophallus ( Fig. 16 ) similar to Monolepta gracilipes Chûjô ( Fig. 17 ), but lateral spiculae slender, most exterior pair of lateral anterior curved.

Female. Antenna relatively shorter ( Fig. 12 ), about 0.7X length of body. Spermathecal cornu ( Fig. 14 ) slender, dorsally flattened; middle part long, apically and strongly curved, slightly widened near cornu; nodulus spherical, large; proximal spermathecal duct long, widest near nodulus, tightly coiled. Dorsal part of bursa-sclerites ( Fig. 15 ) with teeth at apex, extending into middle of dorsal surface, basally widened; ventral part ( Fig. 13 ) slender, with one row of teeth along inner margin.

Variation. Southern populations (Alishan, Tatachia) have the pronotum brown and the surface wrinkled, and the elytra more elongate (maximal width of elytra to length of elytra 0.53–0.56 [mean = 0.54]).

Distribution ( Fig. 22 ). Monolepta mandibularis is found at 1,500 –3,500 m elevation in Chiayi, Hinchu, Hualien, Ilan, Nantou, and Taoyuan counties.

Type Series. Holotype ♂: “ Mururoahu-Kussya Mt. Taiheizan [= Taipingshan, Ilan] FORMOSA, 13.VIII.1936 Coll. S. Asahina ”, pink label “ 13 VIII 1936 Mururoahu-Kussya TAIHEIZAN”, red label “ Monolepta mandibularis CHÛJÔ ”, blank yellow label ( KUEC). The depository of the three paratypes listed by Chûjô (1962) is unknown.

Specimens Examined (388 specimens). 7♂♂, 5♀♀, Chiayi county, Alishan , 22.IX.2009, leg. C.-F. Lee ; 4♂♂, same but with “leg. M.-H. Tsou ” ; 33♂♂, 31♀♀, Hsinchu county, Kuanwu , 6.XI.2009, leg. H. Lee ; 1♀, Hualien county, Mt. Hituroku (= Jueshan, near Kupaiyang ), 14.VIII.1940, leg. M. Chûjô ; 5♂♂, 3♀♀, Hualien county, Sekigahara (= Kuanyuan ), 14. VIII.1940, leg. M. Chûjô ; 7♂♂, 1♀, Ilan county, Tsuifenghu , 15.VIII.2007, leg. W.T. Liu ; 18♂♂, 4♀♀, Ilan county, Yuanyanghu , 23.VIII.2007, leg. Y.-C. Chang ; 3♂♂, 4♀♀, Nantou county, Mt. Gokan ( Hohuashan ), 14.VIII.1940, leg. M. Chûjô ; 7♂♂, 4♀♀, Nantou county, Sungkang , 13-15.IX.1984, leg. K.S. Lin & S.C. Lin ; 6♂♂, 9♀♀, Nantou county, Tatachia , 30.X.2009, leg. C.-F. Lee ; 1♂, 1♀, same but with “leg. H. Lee”; 21♂♂, 25♀♀, Nantou county, Tsuifeng , 1-3.VIII.1981, leg. T. Lin & W.S. Tang ; 1♀, same locality, 8.XI.1981, leg. S.C. Lin & W.S. Tang ; 11♂♂, 3♀♀, same locality, 1-3.IX.1982, leg. L.Y. Chou & K.C. Chou ; 1♂, same locality, 5.VIII.1984, leg. K.S. Lin ; 32♂♂, 34♀♀, same locality, 12.-14.IX.1984, leg. K.S. Lin & S.C. Lin ; 17♂♂, 49♀♀, Hualien, Tayuling , 12-15.IX.1980, leg. K.S. Lin & C.H. Wang ; 2♂♂, same locality, 6-9.IX.1983, leg. L.Y. Chou & K.C. Chou ; 1♀, Taoyuan county, Tamanshan , 25.VIII.2008, leg. H. Lee. ( TARI, USNM)

Plant associations. Flowers of M. sinensis .

Notes. Miscanthus sinensis usually blooms from August to October. We observed adult M. mandibularis aggregating on flowers of M. sinensis in high mountains ( Figs. 19–20 ) (Kuanwau, in Hinchu county; Tatachia, in Nantou county; Alishan, in Chiayi county; Tsuifenghu and Yuanyanghu, in Ilan county) six times during August and September in 2007–2009. The flowering season probably explains why all historical specimens were collected from August to November.

Figures

Figs. 1–6. Dorsal and ventral habiti of Monolepta spp. 1) M. mandibularis, dorsal view; 2) M. mandibularis, ventral view; 3) M. meihuai, dorsal view; 4) M. meihuai, ventral view; 5–6) M. meihuai, color variations.

Figs. 7–15. Monolepta mandibularis. 7) Median lobe, dorsal view; 8) Median lobe, lateral view; 9) Median lobe, ventral view; 10) Male antennomeres I-IV; 11) Male antenna; 12) Female antenna; 13) Ventral bursa-sclerites; 14) Spermatheca; 15) Dorsal bursa-sclerites. Figs. 7–9 drawn to same scale; Figs. 11 and 12 drawn to same scale.

Figs. 16–18. Spiculae of endophallus of Monolepta spp. 16) M. mandibularis; 17) M. gracilipes; 18) M. meihuai.

Figs. 22–23. Distribution maps. 22) Monolepta mandibularis; 23) Monolepta meihuai.

Figs. 19–21. Field observations. 19–20) Monolepta mandibularis; 21) Monolepta meihuai.