Using genotype-by-sequencing to uncover the population history of fungus farming ambrosia beetles

Ambrosia and bark beetles (Coleoptera: Curculionidae: Scolytinae, Platypodinae) are immensely diverse group of tiny fungus farming insects. In addition to fungus farming, many ambrosia beetles display unique reproductive systems.  A single female produces a single haploid male and multiple diploid females. Newly hatched males then mate with their sisters. This capacity to mate within a family, together with their food source – symbiotic fungus – allowed ambrosia beetles to be ecological generalists and colonize most of the world. Despite their ecological and  genetic uniqueness and their increasing economic importance as  exotic pests, little is known about the population history and dynamics of the beetles. This is in part due to the lack of genomic tools developed to study these small and common species. Here we combine high-throughput genomic marker discovery and genotyping using restriction site associated DNA (RAD) sequencing to examine the population history of one of the world’s most widespread ambrosia beetles Xylosandrus crassiusculus. We used two restriction enzymes to reduce the size of the X. crassiusculus genome into fragments that are the same size and that are shared among individuals for Illumina sequencing. The thousands of new alleles generated will allow us to examine the global population structure of one of the most widespread species of animals. Data are being analyzed at the time of submitting the abstract.