Cryptic genetic variation in an inbreeding and cosmopolitan pest revealed using ddRADseq

Each year new exotic species are transported across the world through global commerce. Many of these exotics never become successfully established, but some turn into destructive pests threatening economic and environmental resources. Some of the most widespread exotic species are haplo-diploid ambrosia beetles. One of the fastest spreading ambrosia beetle pests is Xylosandrus crassiusculus. In order to discover the source populations of this globally invasive species and track its human-assisted movement around the world we used restriction site associated DNA sequencing (RADseq). The RADseq approach is combined here with a comprehensive sample of the world’s populations of X. crassiusculus, from locations across the species native and introduced range.