Genome-scale phylogeography resolves the native population structure of the Asian longhorned beetle, Anoplophora glabripennis (Motschulsky)

Human assisted movement has allowed the Asian longhorned beetle (ALB,
Anoplophora glabripennis (Motschulsky)) to spread beyond its native range
and become a globally regulated invasive pest. Within its native range of
China and the Korean peninsula, human-mediated dispersal has also caused
cryptic translocation of insects, resulting in population structure
complexity. Previous studies used genetic methods to detangle this
complexity but were unable to clearly delimit native populations which is
needed to develop downstream biosurveillance tools. We used genome-wide
markers to define historical population structure in native ALB
populations and contemporary movement between regions. We used
genotyping-by-sequencing to generate 6,102 single nucleotide polymorphisms
(SNPs) and amplicon sequencing to genotype 53 microsatellites. In total,
we genotyped 712 individuals from ALB’s native distribution. We observed
six distinct population clusters among native ALB populations, with a
clear delineation between northern and southern groups. Most of the
individuals from South Korea were distinct from populations in China. Our
results also indicate historical divergence among populations and suggest
limited large-scale admixture, but we did identify a restricted number of
cases of contemporary movement between regions. We identified SNPs under
selection and describe a clinal allele frequency pattern in a missense
variant associated with glycerol kinase, an important enzyme in the
utilization of an insect cryoprotectant. We further demonstrate that small
numbers of SNPs can assign individuals to geographic regions with high
probability, paving the way for novel ALB biosurveillance tools.