Xyleborus affinis Eichhoff

Barnouin, Thomas, Soldati, Fabien, Roques, Alain, Faccoli, Massimo, Kirkendall, Lawrence R., Mouttet, Raphaëlle, Daubree, Jean-Baptiste & Noblecourt, Thierry, 2020, Bark beetlesand pinhole borers recently ornewly introduced toFrance (Coleoptera Curculionidae, Scolytinae and Platypodinae), Zootaxa 4877 (1), pp. 51-74 : 59-60

- Xyleborus affinis Eichhoff

( Figs. 2A, 2B )

Distribution. The pantropical distribution of X. affinis reflects a combination of ancient and recent inter- and intracontinental dispersal events ( Gohli et al. 2016). It is one of the most common and widespread species of Scolytinae . Reported for the first time in Europe in 1950 in Belgium, it was later detected in Switzerland and Germany in 1955 and in Italy in 1966 ( Cola 1971, 1973; Merkl & Tusnádi 1992). It was then detected in imported ornamental plants in Hungary in 1990 ( Merkl & Tusnadi 1992) and Italy in 1992 ( Carrai 1992). Finally, in 2006, it was found in natural environments in Austria ( Holzer 2007). Although individuals of this species were caught in 2016 in the French port area of La Rochelle, no data suggests that this species may be established in France since no insects were trapped near the port by similarly-baited traps.

New records: CHARENTE-MARITIME – La Rochelle, port area, interception trap baited with ethanol 100%, (-) α-pinene, and a pheromone blend for longhorn beetle, from 04.VII. to 25.VII. 2016, 9 ind., URZF leg .

Biology and ecology. X. affinis is an extremely polyphagous ambrosia beetle species, reported from about 248 host plants, both broadleaf trees and conifers, without any specific preference ( Schedl 1963; Wood & Bright 1992). In Europe, the species has been found in ornamental plants of the genus Dracaena imported from Central America ( Carrai 1992; Merkl & Tusnadi 1992). In its native range, this ambrosia beetle bores galleries in the xylem of weakened, injured or recently cut trees, but occasionally may infest also healthy trees ( Sobel et al. 2018). Xyleborus affinis is a highly selective species according to wood moisture and decay, preferring large and very moist wood of recently dead trees ( Sobel et al. 2018). For this reason, X. affinis can be particularly abundant in undebarked trunks partially immersed or left on wet soils.

Damage and infestation risk. X. affinis carry the pathogenic fungus Raffaelea lauricola TC Harr., Fraedrich & Aghayeva , which causes a disease lethal for many Lauraceae tree species, but it is not an effective vector ( Carrillo et al. 2013). Moreover, X. affinis is well-known for causing structural damage to fresh timber, particularly on moist soil, decreasing its quality and the economic value ( Sobel et al. 2018).

Figures

FIGURE 2. Xyleborus affinis Eichhoff (2.2 mm). A. dorsal view; B. lateral view. Xyleborus bispinatus Eichhoff (2.8 mm). C. dorsal view; D. lateral view. Xyleborus ferrugineus (Fabricius) (2.4 mm). E. dorsal view. Xyloterinus politus (Say) (3.4 mm). F. dorsal view. Length of specimens in brackets. (Photos: Fabien Soldati).