Euwallacea fornicatus (Eichhoff, 1868)

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 fornicatus (Eichhoff, 1868) Fig. 54G, H, L

Xyleborus fornicatus Eichhoff, 1868b: 151.

Euwallacea fornicatus (Eichhoff): Wood 1989: 173.

Xyleborus fornicatus fornicatus Eichhoff, 1868: Beeson 1930: 234.

Xyleborus whitfordiodendrus Schedl, 1942a: 189. Synonymy: Wood 1989: 173; Smith et al. 2019b: 6.

Xyleborus tapatapaoensis Schedl, 1951b: 152. Synonymy: Wood 1989: 173.

Type material.

Lectotype Xyleborus fornicatus (MIZ). Lectotype Xyleborus tapatapaoensis (NHMW). Lectotype Xyleborus whitfordiodendrus (NHMW).

Diagnosis.

2.6-2.7 mm long (mean = 2.66 mm; n = 5); 2.25-2.36 × 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 8 or 9 socketed denticles, denticles small, their sockets small; declivital surface shiny; declivital interstriae bearing sparse small granules; declivital posterolateral 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. fornicatus 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. kuroshio and E. perbrevis 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.

China (Chongqing, Guizhou, Hong Kong, Yunnan), India (Uttar Pradesh), Japan (Bonin Is, Okinawa), East Malaysia, Samoa, Sri Lanka, Taiwan, Thailand, and Vietnam. This species has been introduced into Israel, South Africa, and the United States (California) (cited as PSHB and/or E. whitfordiodendrus ; Stouthamer et al. 2017, Gomez et al. 2018b). Distribution records published prior to Smith et al. (2019b) may not reflect actual species distribution.

Host plants.

Strongly polyphagous and has been reported from Sambucus ( Adoxaceae ), Liquidambar ( Altingiaceae ), Schinus ( Anacardiaceae ), Alnus ( Betulaceae ), Cunninghamia ( Cupressaceae ), Ricinus ( Euphorbiaceae ), Acacia , Albizia , Bauhinia , Callerya , Erythrina , Robinia ( Fabaceae ), Carya , Quercus ( Fagaceae ), Juglans ( Juglandaceae ), Persea , Umbellaria ( Lauraceae ), Magnolia ( Magnoliaceae ), Ochroma ( Malvaceae ), Ficus , Milicia , Morus ( Moraceae ), Eucalyptus ( Myrtaceae ), Fraxinus ( Oleaceae ), Platanus ( Platanaceae ), Prunus ( Rosaceae ), Populus , Salix ( Salicaceae ), Acer ( Sapindaceae ), Ailanthus ( Simaroubaceae ), and Ulmus ( Ulmaceae ) ( Smith et al. 2019b).

Remarks.

This species is commonly known as the Polyphagous Shot Hole Borer (PSHB) and has been referred to as this and its synonym E. whitfordiodendrus in numerous publications before the species complex was reassessed by Smith et al. (2019b) (e.g., Cooperband et al. 2016; Stouthamer et al. 2017; Papp et al. 2018; Gomez et al. 2018b). Due to longstanding confusion of E. fornicatus with E. fornicatior and E. perbrevis it is quite difficult to unravel 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. 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 Mendel et al. (2012), Eskalen et al. (2013), Freeman et al. (2013), O’Donnell et al. (2015) Chen et al. (2016) Cooperband et al. (2016), Stouthamer et al. (2017).

Figures

Figure 54. Dorsal, lateral and declivital view of Euwallacea andamanensis, 2.8 - 3.4 mm (A, B, I), E. destruens, 3.9 - 4.6 mm (C, D, J), E. fornicatior, 2.20 - 2.37 mm (E, F, K), and E. fornicatus, 2.6 - 2.7 mm (G, H, L).