Xyleborus volvulus (Fabricius, 1775)

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

Xyleborus volvulus (Fabricius, 1775) Fig. 91E, F, K

Bostrichus volvulus Fabricius, 1775: 454.

Hylesinus volvulus (Fabricius): Fabricius 1801: 394.

Xyleborus volvulus (Fabricius): Eggers 1929: 47.

Xyleborus torquatus Eichhoff, 1868b: 146. Synonymy: Wood 1960: 69.

Xyleborus alternans Eichhoff, 1869: 280. Synonymy: Eggers 1929: 43.

Xyleborus badius Eichhoff, 1869: 280. Synonymy: Wood 1960: 69.

Xyleborus interstitialis Eichhoff, 1878b: 375. Synonymy: Wood 1982: 833.

Xyleborus guanajuatensis Dugès, 1887: 141. Synonymy: Wood 1983: 650.

Xyleborus grenadensis Hopkins, 1915a: 62, 65. Synonymy: Wood 1972: 200.

Xyleborus hubbardi Hopkins, 1915a: 62, 65. Synonymy: Schedl 1952d: 164.

Xyleborus rileyi Hopkins, 1915a: 62, 65. Synonymy: Bright 1968: 1318.

Xyleborus schwarzi Hopkins, 1915a: 62, 65. Synonymy: Bright 1968: 1318.

Xyleborus continentalis Eggers, 1920: 42. Synonymy: Beaver 2011: 285.

Xyleborus silvestris Beeson, 1929: 241. Synonymy: Wood 1989: 177.

Xyleborus vagabundus Schedl, 1949: 277. Synonymy: Wood 1972: 200.

Xyleborus granularis Schedl, 1950b: 898. Synonymy: Wood 1989: 177.

Type material.

Holotype Xyleborus continentalis (MFNB). Holotype Xyleborus silvestris (NHMUK).

Diagnosis.

2.5 mm long (mean = 2.5 mm; n = 5); 3.13 × as long as wide. This species is distinguished by the protibiae obliquely triangular, broadest at distal 1/3; declivity smooth, shiny (specimen must be dry); declivital interstriae 1 and 3 armed with two or three pairs of moderate tubercles; interstriae 2 sparsely granulate along its entire length; and elytra unicolored.

This species is almost identical to X. perforans , which is distinguished by its stouter form (2.67-2.89 × as long as wide), and interstriae 2 granules only present at declivity summit.

Similar species.

Xyleborus affinis , X. cognatus , X. ferrugineus , X. festivus , X. perforans , X. pfeilii .

Distribution.

Probably of American origin ( Wood 2007; Gohli et al. 2016) but now in temperate and tropical regions around the world. In the study region recorded from India (Nicobar Is), Bangladesh, Myanmar, Taiwan, Thailand.

Host plants.

Strongly polyphagous ( Browne 1961b; Schedl 1963a, as X. torquatus ).

Remarks.

Specimens from Southeast Asia were not available for examination. The measurements and diagnosis are based on specimens from Panama (Panama) and the United States (Florida).

Wood and Bright (1992) considered reports of the species ranging from Southeast Asia to the Southwest Pacific as referring to X. perforans . Some of the records from the countries of the study region given above may refer to X. perforans ( Beaver et al. 2014). However, molecular studies have confirmed that the species does occur in Bangladesh and Thailand ( Gohli et al. 2016).

Wood and Bright (1992) postulated that X. pfeilii is a synonym of X. volvulus and this was further suggested by Gomez et al. (2018a). Though appearing quite similar, the protibiae of these species are different. That of X. pfeilii is distinctly triangular while that of X. volvulus is obliquely triangular. Analysis of COI and CAD sequences has also shown that these species are separate lineages ( Cognato et al. 2020b) and the validity of X. pfeilii is supported.

Figures

Figure 91. Dorsal, lateral and declivital view of Xyleborus singhi paratype, 1.9 - 2.4 mm (A, B, I), X. sunisae holotype, 2.7 - 2.75 mm (C, D, J), X. volvulus, 2.5 mm (E, F, K), and X. yunnanensis paratype, 2.7 - 2.75 mm (G, H, L).