Simulated flood-stress and X-ray tomography unveil susceptibility of different tree taxa to ambrosia beetles

Authors: CAMBRONERO-HEINRICHS, J - Universita Di Padova; SANTOJEMMA, G - Universita Di Padova; BATTISTI, A - Universita Di Padova; CAVALETTO, G - Universita Di Padova; MEGGIO, F - Universita Di Padova; Ranger, Christopher; SCABBIO, E - Universita Di Padova; RASSATI, D - Universita Di Padova

Submitted to: Forest Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2024
Publication Date: 7/2/2024
Citation: Cambronero-Heinrichs, J.C., Santojemma, G., Battisti, A., Cavaletto, G., Meggio, F., Ranger, C.M., Scabbio, E., Rassati, D. 2024. Simulated flood-stress and X-ray tomography unveil susceptibility of different tree taxa to ambrosia beetles. Forest Ecology and Management. 568. Article 122106. https://doi.org/10.1016/j.foreco.2024.122106.
DOI: https://doi.org/10.1016/j.foreco.2024.122106

Interpretive Summary: Climate change will lead to higher frequencies of natural disasters, including flooding events. As a consequence, more severe and widespread attacks by ambrosia beetles associated with stressed trees are predicted to occur. In this scenario, understanding which tree species are expected to be more susceptible, as well as which ambrosia beetle species could be expected to have the biggest impacts, represent a research priority. To this aim, potted-trees of eight tree species of trees were exposed to flood-stress. An imaging technique, X-ray tomography, was then used to characterize the ambrosia beetle tunneling and gallery formation in the stems of trees. Experimental flooding induced infestations by invasive and native ambrosia beetle species. Certain tree species were preferred over others according to the preference of ambrosia beetles. Certain tree species were also most suitable for ambrosia beetle reproduction. The invasive ambrosia beetle Xylosandrus crassiusculus was the most aggressive and successful species. Our study showed a differential susceptibility of common tree species to ambrosia beetle attacks in a scenario of increasing flood-stress. X-ray tomography of infestations is a novel method for ambrosia beetles and can be considered a reliable methodology to improve our comprehension of the mechanisms underpinning insect´s host selection and colonization.

Technical Abstract: Climate change will lead to higher frequencies of natural disasters, including flooding events. As a consequence, more severe and widespread attacks by ambrosia beetles associated with stressed trees are predicted to occur. In this scenario, understanding which tree species are expected to be more susceptible, as well as which ambrosia beetle species could be expected to have the biggest impacts, represent a research priority. To this aim, potted-trees of eight tree species (four in the order Fagales and four in the order Rosales) were exposed to flood-stress and then analyzed through X-ray tomography to evaluate host selection patterns, colonization success, and potential damage to the tree by a number of native and exotic ambrosia beetle species. Four ambrosia beetle species attacked flood-stressed trees, the native Anisandrus dispar and Xyleborinus saxesenii, and the exotic Xylosandrus crassiusculus and Xylosandrus germanus. Rosales tree species were consistently more attacked than the Fagales trees, but the different ambrosia beetle species showed different preferences for certain tree species. Rosales were also generally more suitable for ambrosia beetle reproduction than Fagales, even if species-specific patterns were also evident. The exotic X. crassiusculus was the most aggressive and successful species. Our study showed a differential susceptibility of common tree species to ambrosia beetle attacks in a scenario of increasing flood-stress. X-ray tomography of infestations is a novel method for ambrosia beetles and can be considered a reliable methodology to improve our comprehension of the mechanisms underpinning insect´s host selection and colonization.