Cnestus mutilatus (Blandford, 1894)

Smith, Sarah M., Beaver, Roger A. & Cognato, Anthony I., 2020, A monograph of the Xyleborini (Coleoptera, Curculionidae, Scolytinae) of the Indochinese Peninsula (except Malaysia) and China, ZooKeys 983, pp. 1-442 : 1

Cnestus mutilatus (Blandford, 1894) Fig. 33C, D, J

Xyleborus mutilatus Blandford, 1894b: 103.

Xylosandrus mutilatus (Blandford): Wood 1989: 177.

Cnestus mutilatus (Blandford): Dole and Cognato 2010: 530.

Xyleborus sampsoni Eggers, 1930: 184. Synonymy: Wood 1989: 177.

Xyleborus banjoewangi Schedl, 1939b: 41. Synonymy: Kalshoven 1960: 63.

Xyleborus taitonus Eggers, 1939b: 118. Synonymy: Wood and Bright 1992: 799.

Type material.

Holotype Xyleborus mutilatus (NHMUK).

New records.

China: Hong Kong, Tai Po Kau, vi.2017, J. Skelton, ex Liquidambar (MSUC, 1). Jiangsu, Nanjing, Laoshan National Park, Bacai Road, 32.09156N, 118.583701E, 15.viii.2017, Cognato, Li, Gao (MSUC, 2). Jiangxi, Nan Chang, 11.iv.2016, Lv-Jia, ex Morus alba (RABC, 1). Shanghai, Dongchuan, vii-viii.2017, Gao, ex trap w/ querciverol (MSUC, 4). Vietnam: Cao Bang, 22°33.118'N, 105°52.537'E, 1048 m, 12-17.vi.2014, VN9, Cognato, Smith, Pham, FIT (MSUC, 1).

Diagnosis.

3.6-3.8 mm long (mean = 3.76 mm; n = 5); 1.58-1.73 × as long as wide. This species is distinguished by the presence of a mesonotal mycangial tuft on the pronotal base; elytral disc very short, 2 × scutellum length; declivity obliquely truncate; pronotum type 1 when viewed dorsally; antennal club type 2, with two sutures visible on posterior face; antennal funicle 4-segmented; protibiae obliquely triangular; procoxae narrowly separated; declivital posterolateral margin weakly carinate from apex to declivital base along interstriae 7; declivital interstriae granulate, with recumbent hair-like setae, often a median row of long erect hair-like setae on upper part of declivity (varies geographically); interstriae 2 and 3 with three or four rows of setae; declivital striae 1 and 2 impressed; discal punctures dense, confused, surface between punctures with only traces of reticulation; and uniformly black body.

Similar species.

Anisandrus ursulus , Cnestus ater , C. gravidus , C. improcerus , C. testudo .

Distribution.

Throughout the Oriental region from India to Indonesia and New Guinea, and extending northwards to Japan, Korea, and Russia (Far East). Introduced and established in the United States ( Schiefer and Bright 2004; Gomez et al. 2018a). Recorded in the study region from China (Anhui, Fujian, Guizhou, Hainan, Hong Kong*, Jiangsu*, Jiangxi*, Shaanxi, Shanghai*, Sichuan, Yunnan, Zhejiang), South Korea, Taiwan, Vietnam*.

Host plants.

Polyphagous ( Wood and Bright 1992).

Remarks.

The biology of the species has been studied in Japan by Kajimura and Hijii (1992, 1994), in China by Tang (2000), and in USA by Stone and colleagues ( Stone and Nebeker 2007; Stone et al. 2007). The associated ambrosia fungus has been described by Six et al. (2009). It is a pest of young Castanea mollissima ( Fagaceae ) trees in China (Zhejiang) ( Tang 2000), but in USA appears to favor stressed host plants ( Stone et al. 2007). Cnestus mutilatus is also strongly attracted to ethanol and has been reported to bore holes in and damage plastic gasoline containers ( Carlton and Bayless 2011).

Figures

Figure 33. Dorsal, lateral and declivital view of Cnestus improcerus, 2.7 - 3.3 mm (A, B, I), C. mutilatus, 3.6 - 3.8 mm (C, D, J), C. nitidipennis, 2.8 - 3.2 mm (E, F, K), and C. protensus, 3.3 - 5.4 mm (G, H, L).