Xyleborinus saxesenii (Ratzeburg, 1837)

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

Xyleborinus saxesenii (Ratzeburg, 1837) Fig. 85A, B, I

Bostrichus saxesenii Ratzeburg, 1837: 167.

Xyleborinus saxesenii (Ratzeburg): Reitter 1913: 79.

Xyleborus dohrni Wollaston, 1854: 290. Synonymy: Eichhoff 1878b: 362.

Xyleborus decolor Boieldieu, 1859: 473. Synonymy: Ferrari 1867: 22.

Xyleborus aesculi Ferrari, 1867: 22. Synonymy: Eichhoff 1878b: 362.

Xyleborus sobrinus Eichhoff, 1876a: 202. Synonymy: Schedl 1964d: 313.

Xyleborus subdepressus Rey, 1883: 142. Synonymy: Bedel 1888: 419.

Xyleborus frigidus Blackburn, 1885: 193. Synonymy: Samuelson 1981: 59.

Xyleborus floridensis Hopkins, 1915a: 60, 63. Synonymy: Wood 1962: 79.

Xyleborus pecanis Hopkins, 1915a: 60, 63. Synonymy: Wood 1962: 79.

Xyleborus quercus Hopkins, 1915a: 60, 63. Synonymy: Wood 1962: 79.

Xyleborus arbuti Hopkins, 1915a: 61, 64. Synonymy: Wood 1957: 403.

Xyleborinus tsugae Swaine, 1934: 204. Synonymy: Wood 1957: 403.

Xyleborinus librocedri Swaine, 1934: 205. Synonymy: Wood 1957: 403.

Xyleborus pseudogracilis Schedl, 1937c: 169. Synonymy: Wood 1989: 176.

Xyleborus retrusus Schedl 1940b, 208. Synonymy: Wood 1989: 176.

Xyleborus peregrinus Eggers, 1944: 142. Synonymy: Schedl 1980: 122.

Xyleborus pseudoangustatus Schedl, 1948: 28. Synonymy: Schedl 1964d: 313.

Xyleborus paraguayensis Schedl, 1949: 276. Synonymy: Wood 1989: 176.

Xyleborus opimulus Schedl, 1976: 77. Synonymy: Wood 2007: 473.

Type material.

Holotype Xyleborus floridensis (NMNH). Holotype Xyleborus pecanis (NMNH). Holotype Xyleborus quercus (NMNH).

New records.

China: Chongqing, Jinfo Mtn, 9.v.2016, Tian-Shang, Lv-Jia, ex Ficus sp. (RABC, 2). Hong Kong, Kadoorie Farm, vi.2017, J. Skelton (UFFE, 1). Shanghai, Dongchuan, vii-viii.2017, Gao, ex trap w/ querciverol (MSUC, 4). Vietnam: Cao Bang, 22°36.402'N, 105°52.397'E, 1601 m, 13.iv.2014, VN17, Cognato, Smith, Pham, ex standing stump (MSUC, 1).

Diagnosis.

2.3-2.5 mm long (mean = 2.34 mm; n = 5); 3.13-3.29 × as long as wide. This species is distinguished by the declivital face with interstriae 2 armed by granules at declivital summit, unarmed on declivital face; declivital interstriae 1 and 3 denticles subacutely pointed; denticles on ventrolateral areas of the elytra small, less acute; discal interstriae 1 and 2 unarmed; declivital interstriae 2 flattened; and moderate size.

Similar species.

Xyleborinus attenuatus , X. subgranulatus , X. subspinosus , X. thaiphami .

Distribution.

Occurs throughout the Palaearctic region. Recorded in the study region from China (Anhui, Chongqing*, Fujian, Guangxi, Guizhou, Hebei, Heilongjiang, Hong Kong*, Hunan, Jiangsu, Jiangxi, Jilin, Ningxia, Shaanxi, Shanghai*, Shanxi, Sichuan, Xizang, Yunnan, Zhejiang), India (Assam, Kashmir, Uttarakhand, West Bengal), Taiwan, Vietnam. Outside the Palaearctic, introduced and established in American Samoa, Australia, Hawaii, New Zealand, South Africa, North America (Canada, United States, Mexico) and several countries in South America ( Wood and Bright 1992; Kirkendall 2018).

Host plants.

Strongly polyphagous attacking both gymnosperms and angiosperms ( Wood and Bright 1992).

Remarks.

The biology of the species has been studied by Fischer (1954), Egger (1973), Hosking (1973), Peer and Taborsky (2007), Biedermann (2010), Biedermann and Taborsky (2011) and others. The larvae enlarge the gallery system as they develop, and frequently feed on fungus-infested wood rather than the ambrosia fungus alone ( Wood 1982; Biedermann et al. 2009). Peer and Taborsky (2007) show that cooperative brood care occurs within the gallery system as a result of delayed dispersal by the new generation of females and that this can raise the number of offspring produced per gallery. The species is strongly attracted to ethanol (e.g., Markalas and Kalapanida 1997; Saruhan and Akyol 2012). It is a pest of hazelnut in the Mediterranean area ( Saruhan and Akyol 2012), and of stressed trees in fruit orchards and forest plantations. Damage to timber is also caused by the galleries and associated staining of the wood ( Chararas 1962).

Figures

Figure 85. Dorsal, lateral and declivital view of Xyleborinus saxesenii, 2.3 - 2.5 mm (A, B, I), X. schaufussi, 2.5 - 3.1 mm (C, D, J), X. sculptilis paratype, 2.1 - 2.25 mm (E, F, K), and X. speciosus holotype, 2.6 - 2.7 mm (G, H, L).