The bark and ambrosia beetles of Bhutan (Coleoptera: Curculionidae: Scolytinae and Platypodinae): a synopsis with three new species of Scolytinae Author Beaver, Roger A. 161 / 2 Mu 5, Soi Wat Pranon, T. Donkaew, A. Maerim, Chiangmai 50180, Thailand. Author Smith, Sarah M. 0000-0002-5173-3736 Department of Entomology, Michigan State University, 288 Farm Lane, 243 Natural Science Bldg., East Lansing, MI 48824, USA. smith 462 @ msu. edu; https: // orcid. org / 0000 - 0002 - 5173 - 3736 smith462@msu.edu text Zootaxa 2022 2022-08-08 5174 1 1 24 journal article 115950 10.11646/zootaxa.5174.1.1 c4bf1061-5af8-4f4a-b4ca-234b6d0ca615 1175-5326 6972960 F80F144B-D1E8-4587-A146-0BACFFE18FB6 Xylosandrus crassiusculus (Motschulsky) Phloeotrogus crassiusculus Motschulsky, 1866: 403 . Xylosandrus crassiusculus (Motschulsky) : Wood 1977: 68 . Xyleborus semiopacus Eichhoff, 1878: 334 . Synonymy: Wood 1969: 119 . This species was recorded from Bhutan by Schedl (1975 as Xyleborus semiopacus Eichhoff ). Distribution. The species is native to and widespread through the Oriental region, extending North to Japan and Korea , and East to New Guinea , Fiji and Samoa ; presumably originally imported to tropical Africa, but now widespread in the Afrotropical region; imported to and established in southern Europe, Australia and the Americas. Biology. The species is strongly polyphagous, and numerous host trees are listed by Dole & Cognato (2010) . The biology and gallery system have been described by Browne (1961) , Schedl (1963) (both as Xyleborus semiopacus ), and Ranger et al. (2016) amongst others. This is a species of economic importance because it can attack and breed in healthy shoots and twigs, although it more usually attacks physiologically stressed plants ( Ranger et al. 2016 ). This can facilitate the introduction of pathogenic fungi (Mayers et al. 2016). It has become a major pest species in the southern USA , especially in fruit tree nurseries. Management strategies are discussed by Ranger et al. (2016 , 2021), Gugliuzzo et al. (2021) , and others.