Population Genetic Diversity of Two Blue Oat Mite Species on Hosts in China.

Blue oat mite species, including and , are pests widely distributed across China that cause damage to winter wheat. This study evaluated the genetic diversity of and on hosts collected from 23 geographic locations based on mitochondrial cytochrome c oxidase subunit I (COI) sequences. We identified nine haplotypes in 438 individuals from 21 geographic locations and five haplotypes in 139 individuals from 11 geographic locations. Meanwhile, exhibits high values of haplotype diversity () and nucleotide diversity () ( = 0.534 > 0.5 and = 0.012 > 0.005), representing a large stable population with a long evolutionary history. shows low values of and ( = 0.112 < 0.5 and = 0 < 0.005), which suggest recent founder events. Moreover, demographic analysis suggested that and have not undergone a recent population expansion. The lowest genetic variation was observed in Xiangzhou (XZ-HB), Zaoyang (ZY-HB), Siyang (SY-JS), and Rongxian (RX-SC), with only one species and one haplotype identified in over 30 individuals. Robust genetic differentiation was found in compared to , which provides a theoretical basis for the widespread distribution of in China.