Genetic isolation of the sorghum plant bug <Emphasis Type="Italic">Stenotus rubrovittatus</Emphasis> (Hemiptera: Miridae) in Fukushima and Ibaraki prefectures

Population subdivision and connectivity within a distribution range are important factors to consider in the development of a management strategy to control widespread pest species. Damage by sorghum plant bug, Stenotus rubrovittatus (Matsumura), has rapidly spread across Japan over the last 10 years. To characterize the fine-scale population structure of this bug and investigate the boundaries of genetic isolation, we analyzed the population structure of 21 local populations within a 72 km × 200 km area around Fukushima and Ibaraki prefectures. Polymorphism of six microsatellite markers implied that S. rubrovittatus in the study area was divided into northern and southern genetic groups segregated by the 37.3°N line of latitude. The boundary between the two groups, defined by microsatellites, was almost consistent with the range limit of one mitochondrial lineage of the same species. Our result indicated that isolation between these two genetic groups was mediated by historical and ecological origins, and was maintained during the last 10 years when there were rapid outbreaks of this species on rice within the study area.