Abstract
We used two types of molecular markers to analyze the genetic structure of seven populations of Tetranychus kanzawai complex collected from the Tohoku area of northern Honshu, the main island of Japan. For phylogenetic analysis, we used DNA sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene and the internal transcribed spacer 1 (ITS1) region of the ribosomal RNA gene; for detailed analysis of population structure, we used microsatellite markers. We found that all population pairs were differentiated significantly; this differentiation was enhanced significantly by host plant effect but not by geographic distance among the populations. DNA sequencing of ITS1 and COI regions and microsatellite analysis both showed that the population occurring on Pueraria lobata was deviated genetically from the other populations. Therefore, our analysis suggested that population subdivision in T. kanzawai complex developed because of host plant effects rather than geographic barriers.
