2026/01/01 by Jamie You, Xinyi Huang, Shawn D. Mansfield +2 · 1 voice
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · Environmental Science · #Forest Ecology and Biodiversity Studies #Forest Insect Ecology and Management #Plant and Fungal Interactions Research
paper · pdf · doi:10.4039/tce.2026.10060
openalex publication_date 2026/01/01 · openalex created_date 2026/07/22 · openalex updated_date 2026/07/30
Abstract Red alder, Alnus rubra Bongard (Betulaceae), is a keystone hardwood tree species of great ecological importance in riparian, mixed, and recently disturbed forests in the Pacific Northwest of North America. The alder bark beetle, Alniphagus aspericollis (LeConte) (Coleoptera: Curculionidae: Scolytinae), is an insect that infests and kills red alder throughout its range. Recent observations in southwestern British Columbia, Canada, have indicated that widespread red alder mortality may be attributed to attacks by the alder bark beetle. The most studied defence compound in red alder is oregonin, a diarylheptanoid xyloside. Past studies have shown oregonin to generally inhibit lepidopteran herbivory, but no research has investigated its effects on subcortical insects, such as the alder bark beetle. We hypothesised that high oregonin content is related to resistance to alder bark beetle colonisation in red alder. In support of our hypothesis, we found that the phloem oregonin content of trees that were successfully colonised by the alder bark beetle was significantly lower than that of trees that were not attacked and those that resisted colonisation. These results suggest that oregonin may be a defence metabolite in red alder phloem, although further studies are needed to evaluate how oregonin could influence beetle colonisation success.