Symbiotic fungi associated with xyleborine ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) and the imperative of global collaboration

Abstract

Ambrosia beetles from the tribe Xyleborini are part of nearly all forest ecosystems. Because of their small size, haplodiploid mating structure, and protected lives inside the sapwood of woody plants, they have a unique ability to expand into new regions via inadvertent human transport. A small number of invasive xyleborines cause significant damage to forests, lumber concerns, and agricultural systems. Most ambrosia pests damage or kill trees by the accumulation of beetle attacks, one is known to cause tree death through the introduction of pathogenic fungus into susceptible Lauraceae trees. The relationships between ambrosia fungi and their beetle vectors range from mutualistic symbiosis to facultative association, but most remain unstudied. Unresolved taxonomies, convergent morphologies, and the difficulty of sampling ambrosia fungi over their entire global ranges make comprehensive surveys of ambrosia fungi difficult to achieve. Ambrosia fungi from Europe and North America are moderately well documented, however, we have yet to sufficiently document those from Africa, Asia, Australia, and South America. Worldwide cooperation to improve and standardize scientific study of the ambrosia symbioses is needed to better understand these impactful organisms.