Data for: Demographic history of Platypus quercivorus (Coleoptera: Curculionidae), a beetle causing mass mortality of oak trees, in eastern Japan

Abstract
In recent years, Japanese oak wilt (JOW) causing mass mortality of oak trees has exhibited a significant geographical expansion. Understanding the formation history of current local populations of Platypus quercivorus Murayama, a vector of JOW, is important foundational knowledge for effectively preventing forest damage. In this study, we used genome-wide single nucleotide polymorphism data to determine the population genetic structure and historical demography of P. quercivorus populations in eastern Japan, where JOW is rapidly expanding. We found at least three distinct genetic groups, each of which caused JOW in different areas. The supported scenario suggests that one of two genetic groups in the northeast first diverged from the ancestral population, then the other group diverged from the southwestern population, followed by gene flow between the two groups. Recent admixtures of the two northeastern groups were identified at certain sites. The geographic genetic structure of the populations suggested that each genetic group experienced recent range expansion. Although genetically independent populations have caused oak tree mass mortality in their original distribution range, our results support the hypothesis that the recent geographic expansion of JOW outbreaks is attributed to the range expansion of the three P. quercivorus groups.