Ambrosia beetles from the tribe Xyleborini (Coleoptera: Curculionidae: Scolytinae) small, haplodiploid beetles that farm nutritional fungi on the walls of tunnels they excavate in the xylem of dead or nearly dead trees. These biological traits make them successful participants in worldwide wooded ecosystems and facilitate their human-mediated invasion beyond their native ranges. A minority of these introduced species are classified as pests because of the physical damage they cause to their plant hosts, or because they vector pathogenic fungi that infect ornamental, lumber, and forest trees. Most of the current knowledge on the diversity of xyleborine beetles and their fungi centers around species found in North America, Asia, and Europe. Little is known about the ambrosia partnerships in the Neotropics, which is concerning because South America is a strong trading partner with the US and the potential for new invasive Xyleborini to be imported from this area is significant. Continuing forest damage caused by invasive Xyleborini/fungi inspires robust research efforts to describe these symbionts and document their biological traits. Considerable efforts are required to enhance such endeavors in underrepresented regions such as South America and Africa. To increase understanding of the South American Xyleborini and their associated fungi, I compiled current knowledge of their historical and contemporary taxonomic records, biological records, and ecological studies. I also completed surveys throughout Ecuador to collect beetles and fungi. Molecular analysis of fungi isolated from Ecuadorian beetles reveals that several Coptoborus species associate with Fusarium fungi, including the ambrosia Fusarium Clade (AFC) that has previously been recovered from Euwallacea spp. and Xyleborus ferrugineus in Central America, Florida, California, Israel, and Asia. Examination of the morphology of some South American xyleborine specimens previously classified as Coptoborus spp. suggests a high similarity to Xyleborus spp. from Africa. Phylogenetic analysis of these South American and African beetles as well as morphological assessment of additional specimens necessitates the designation of a new genus Xenoxylebora gen. nov. containing species endemic to both continents. This unusual distribution demonstrates the ability of these ambrosia beetles to survive long-distance trans-oceanic dispersal.
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