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Background. Ambrosia beetles include well-known invasive pests, but most species established in non-native areas do not cause any significant impact. Here we report the recent invasion and rapid spread of Ambrosiodmus minor in the Southeastern US.
Methods: We used a combination of a multi-year survey, literature data on fungal symbionts from the beetle mycangia and in vitro bioassays of fungal competition, and extensive field observations of wood colonization patterns.
Results. In less than seven years, A. minor abundance has increased many-fold in Florida. The beetle is associated with an aggressive wood-rot fungus Flavodon ambrosius. Joint colonization of wood by A. minor and F. ambrosius results in extensive white rot (lignin removal). The invasion of this symbiosis may impact an ecosystem function previously considered not influenced by non-native ambrosia beetles: wood decay. We suggest monitoring of the impact of this invasion on native wood-inhabiting organisms, biomass degradation and the carbon cycle throughout the region.
This manuscript reports a seemingly innocuous, but very rapid invasion that is turning out to have unexpected consequences. Ambrosia beetles are known for their impact on living tree ecosystems and industries, but this is the first case in which an ambrosia beetle with a very unusual fungus is beginning to impact wood degradation on a regional scale less than a decade after its establishment in the US. The reason to publish as a pre-print is that a complete dataset on the impact of this symbiosis is not available, and we are not aware of any research group that is collecting such data. Yet the spread of this symbiosis is so rapid, and the impact is substantial but difficult to notice, therefore we would like to notify the community of invasion biologists soon.