Xylosandrus germanus (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

Xylosandrus germanus (Blandford, 1894) Fig. 95E, F, K

Xyleborus germanus Blandford, 1894b: 106.

Xylosandrus germanus (Blandford): Hoffman 1941: 38.

Xyleborus orbatus Blandford, 1894b: 123. Synonymy: Nobuchi 1981b: 31.

Type material.

Syntypes Xyleborus germanus (NHMUK). Holotype Xyleborus orbatus (NHMUK).

New records.

China: Chongqing, Chengkou, 16.vii.2016, Tian-Shang (RABC, 1); as previous except: Jinfo Mtn., 9.v.2016, Tian-Shang, Lv-Jia, ex Taxodiaceae sp. (RABC, 1); as previous except: Pengshui, 11.viii.2016, Tian-Shang (RABC, 1); as previous except: Simian Mtn., 7.v.2016, Tian-Shang, Lv-Jia (RABC, 1). Jiangsu, Nanjing, Laoshan National Park, Bacai Road, 32.09156N, 118.583701E, 15.viii.2017, Cognato, Li, Gao (MSUC, 2). Jiangxi, Nanchang, Jiangxi Agric. Univ. orchard, v.2015, Su, T-L., ex Choerospondias axillaris (RABC, 2); as previous except: Jin Xian, 4.v.2016, Lv-Jia, ex Cinnamomum camphora (RABC, 1); as previous except: Xun Wu, 18.vii.2016, Lv-Jia, Lai, S-C., ex Citrus reticulata (RABC, 1).

Diagnosis.

2.3-2.4 mm long (mean = 2.32 mm; n = 5); 2.3-2.56 × as long as wide. This species is distinguished by its moderate size; elytral disc gradually curving toward declivity, elytra rounded; posterolateral margins of elytra carinate to interstriae 7; declivital face with six punctate striae; declivital interstriae granulate, uniseriate with erect hair-like setae longer than the width of 1.5 interstriae; pronotum 1.1 × long as wide, pronotum from dorsal view rounded (type 1) and lateral view basic (type 0), summit at midpoint, basal 1/2 smooth, shiny, sparsely minutely punctate; and sparse mycangial tuft on the pronotal base.

This species is nearly identical to X. eupatorii and is most easily distinguished by the pronotum 1.1 × as long as wide and the pronotal base with more dense setae and from X. metagermanus by the smaller, shallower strial punctures and feebly impressed striae.

Similar species.

Anisandrus dispar , A. maiche , A. paragogus , Xylosandrus dentipennis , X. eupatorii , X. metagermanus .

Distribution.

China (Anhui, Chongqing*, Fujian, Guangdong, Guangxi, Guizhou, Hainan, Henan, Hubei, Hunan, Jiangsu*, Jiangxi*, Shaanxi, Shanxi, Sichuan, Xizang, Yunnan, Zhejiang), Taiwan, Vietnam. Also present in Japan, Korea, Russia (Far East, Sakhalin, Kurile Is). Introduced to and established in Europe and Turkey, USA (including Hawaii) and Canada ( Gomez et al. 2018a). The record in Dole and Cognato (2010) from Thailand is incorrect. The cited specimens belong to the closely similar species, Xylosandrus eupatorii (see above).

Host plants.

Polyphagous ( Weber and McPherson 1983b; Dole and Cognato 2010).

Remarks.

The basic biology is described by Nobuchi (1981b), Weber and McPherson (1983a), and Ranger et al. (2016). Peer and Taborsky (2004, 2005) have studied male dispersal, variations in sex ratio, and outbreeding depression in the species. Ito et al. (2008) discuss the genetic structure of Japanese populations. Although usually attacking stressed trees, the species sometimes attacks apparently healthy and newly transplanted trees and shrubs (e.g., Nobuchi 1981b; Ranger et al. 2010, 2015). Ranger et al. (2016) discuss the ecology and management of the species in ornamental plant nurseries in USA.

Figures

Figure 95. Dorsal, lateral and declivital view of Xylosandrus eupatorii, 2.0 - 2.3 mm (A, B, I), X. formosae, 2.5 - 3.0 mm (C, D, J), X. germanus, 2.3 - 2.4 mm (E, F, K), and X. jaintianus holotype, 3.0 mm (G, H, L).