Genetic Structure of <i>Monochamus alternatus</i> (Hope) in Qinling‐Daba Mountains and Expansion Trend: Implications for Pest Prevention and Management

Pine wilt disease (PWD), caused by <i>Bursaphelenchus xylophilus</i>, severely threatens global pine forests. <i>Monochamus alternatus</i> is the primary vector of <i>B. xylophilus</i> in East Asia. Understanding the population structure and evolutionary forces of vector insects is critical for establishing effective PWD management strategies. The present work explores the genetic structure and phylogenetic relationships of 20 populations of <i>M. alternatus</i> from the Qinling-Daba Mountains (QDM) in China using the mitochondria DNA dataset, supplemented by ecological niche modeling (ENM). All <i>M. alternatus</i> populations were categorized into three phylogeographic clusters (Clade A, Clade B, and Clade C), with Clade A and Clade B corresponding to the western and eastern QDM, respectively. The results of divergence time estimation concur with environmental changes induced by Quaternary glacial climate oscillations in QDM of China. <i>M. alternatus</i> populations exhibited significant genetic differentiation, with expansion in their population size. Ecological niche modeling (ENM) demonstrated that precipitation and temperature significantly influence the distribution of <i>M. alternatus</i> and the species is anticipated to grow into higher latitude and higher altitude regions in the future. In a nutshell, exploring the genetic structure and evolutionary dynamics of <i>M. alternatus</i> can provide valuable insights into the prevention and occurrence of <i>B. xylophilus</i>. These findings also serve as a reference for research on population differentiation and phylogeography of other species in QDM and adjacent areas.