Euwallacea perbrevis (Schedl, 1951)

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

Euwallacea perbrevis (Schedl, 1951) Fig. 57C, D, J

Xyleborus perbrevis Schedl, 1951a: 59.

Euwallacea perbrevis (Schedl): Wood 1989: 173 (as a synonym of E. fornicatus ).

Xyleborus molestulus Wood, 1975b: 400. syn. nov.

Type material.

Holotype Xyleborus perbrevis (NHMW). Holotype Xyleborus molestulus (NMNH).

Diagnosis.

2.3-2.5 mm long (mean = 2.44 mm; n = 5); 2.46-2.55 × as long as wide. This species is distinguished by the pronotum basic (type 2) when viewed dorsally, anterior margin appearing rounded; declivity rounded; declivital face convex; protibiae outer margins rounded with 7-10 socketed denticles, denticles small, their sockets small; declivital surface shiny; interstriae bearing sparse small granules; and posterolateral declivital margin costate. This species is part of the Euwallacea fornicatus species complex and the most reliable method to ensure accurate identification of these species is through generation of COI barcoding sequences ( Gomez et al. 2018b; Smith et al. 2019b). Specimens of E. perbrevis can be morphologically diagnosed through a combination of overlapping elytral and pronotal measurements and number of socketed denticles on the protibiae given in Table 2 .

This species is nearly identical to E. geminus and E. malloti and can be separated by the elytral bases rounded and posterolateral declivital costa carinate and never granulate.

Similar species.

This species is part of the Euwallacea fornicatus species complex along with E. fornicatior , E. fornicatus , E. kuroshio from which it is difficult to distinguish. The species is also similar to E. andamanensis , E. geminus , E. malloti , E. neptis , E. semirudis , E. testudinatus , E. velatus , and Xylosandrus formosae .

Distribution.

This species occurs in American Samoa, Australia, Brunei, China (Hainan), Fiji, Indonesia (Java), Japan (Okinawa), East & West Malaysia, New Guinea, Palau, Philippines, Réunion, Singapore, Sri Lanka, Taiwan, Thailand, Timor Leste, Vietnam, and introduced in the United States (Florida and Hawaii) ( Gomez et al. 2018b), Costa Rica and Panama ( Kirkendall and Ødegaard 2007, reported as E. fornicatus ) ( Smith et al. 2019b).

Host plants.

The species is strongly polyphagous and has been recorded from 13 families: Avicennia ( Acanthaceae ), Mangifera ( Anacardiaceae ), Annona ( Annonaceae ), Cyathocalyx , Xylopia ( Annonaceae ), Bursera , Protium ( Burseraceae ), Terminalia ( Combretaceae ), Aleurites ( Euphorbiaceae ), Acacia , Albizia , Erythrina , Lysiloma ( Fabaceae ), Theobroma and Trichospermum ( Malvaceae ), Cedrela ( Meliaceae ), Artocarpus , Brosimum ( Moraceae ), Myristica ( Myristicaceae ), Citrus ( Rutaceae ), Casearia ( Salicaceae ), Litchi ( Sapindaceae ), and Camellia sinensis ( Theaceae ) ( Smith et al. 2019b).

Remarks.

Xyleborus molestulus Wood was described from specimens collected in the Panama Canal Zone and western Panama in 1963. Wood (1982: 775) later transferred the species to the endemic Neotropical genus Theoborus Hopkins, 1915 presumably because of similar morphological features. In 1982 Wood reported Xyleborus fornicatus from the Canal Zone from specimens collected in 1979. Based on a recent revision of the E. fornicatus species complex, E. perbrevis was recognized as the species of the complex occurring in Panama ( Gomez et al. 2018b, Smith et al. 2019b). The X. molestulus and E. perbrevis holotypes and specimens collected from the Canal Zone (MSUC) are identical.

Euwallacea perbrevis was previously thought to be a synonym of E. fornicatus ( Wood 1989; Gomez et al. 2018b) but a subsequent reanalysis of the complex by Smith et al. (2019b) showed that the species is a distinct lineage. This species is commonly known as the Tea Shot Hole Borer (TSHB) and has been referred to as this, as well as E. fornicatus , which it was misidentified as in numerous publications before the species complex was reassessed by Smith et al. (2019b). Due to longstanding confusion of E. perbrevis with E. fornicatior and E. fornicatus it is quite difficult to untangle the published accounts of the biology of each species. All three species occur sympatrically on Sri Lanka where most of the natural history studies were undertaken and where E. perbrevis is a serious pest of tea plantations. See the discussion on the identity of the tea shot hole borer in Smith et al. (2019b).

Various aspects of the biology of the species are described by Freeman et al. (2013), O’Donnell et al. (2015), Chen et al. (2016), Cooperband et al. (2016), Stouthamer et al. (2017) and Lynn et al. (2020).

Figures

Figure 57. Dorsal, lateral and declivital view of Euwallacea neptis holotype, 4.2 mm (A, B, I), E. perbrevis, 2.3 - 2.5 mm (C, D, J), E. piceus, 2.2 - 2.6 mm (E, F, K), and E. semiermis lectotype, 2.5 - 2.75 mm (G, H, L).