The scent of a partner: ambrosia beetles are attracted to volatiles from their fungal symbionts.

Invasive fungus-growing ambrosia beetles are an emerging threat to forest ecosystems and fruit industries, but management tools are lacking. Here we explored the potential of beetle symbionts-ambrosia fungi-as a source of attractants. Our focus was the redbay ambrosia beetle, Xyleborus glabratus, and its symbiotic fungus, Raffaelea lauricola, which are devastating lauraceous hosts in the southeastern United States. We also tested three additional co-occurring beetle species and their symbionts. Each beetle species was consistently attracted to the odors of its symbiotic fungal species, occasionally also to symbionts of other species, but never to non-symbiotic Trichoderma. We further confirmed attraction to ethanol (positive control) in some species. Thus, ambrosia fungi produce volatiles attractive to their vector beetles, which may have potential as novel lures for ambrosia beetle management.