Resolution of a cryptic species complex in inbred ambrosia beetles using a combination of molecular phylogenetics and careful morphological assessment

Euwallacea fornicatus, or rather an impostor, is invading California, Florida, and Israel and spreading disease to avocados. This tiny, fungus-farming ambrosia beetle vectors a newly described fungus (Fusarium euwallaceae) which seems to have a very broad range of host trees. The beetle and its fungus have been found on a broad variety of woody plants in their introduced range, but are of special concern on avocado. The imposter was thought to be identical to E. fornicatus, but our four-gene population structure analysis discovered two distinct species, each with a different ecology and causing different levels of damage. Using a combination of molecular phylogenetic analysis and careful assessment of morphological characters, we have discovered a suite of characters to help insect identifiers on the front lines of invasion prevention tell these two species apart.