Mitochondrial diversity and population structure of Matsucoccus matsumurae across South Korea

Matsucoccus matsumurae is an important pine pest in East Asia, but its mitochondrial diversity and population structure across South Korea have not been assessed nationwide. We analyzed mitochondrial ND5 (603 bp; n = 356) and CytB (550 bp; n = 329) sequences from 24 populations to evaluate haplotype diversity, population structure, and isolation by distance. We identified 27 ND5 and 24 CytB haplotypes; concatenated sequences (1,153 bp) from 320 individuals yielded 55 composite mitochondrial haplotypes. For both markers, nucleotide diversity was low, dominant haplotypes were shared among distant localities, and haplotype networks showed shallow sequence divergence. Nevertheless, substantial differentiation occurred between many population pairs, with pairwise F ST reaching 0.953 in the concatenated dataset. This differentiation showed no consistent regional arrangement, and BAPS clusters were not geographically restricted. Mantel tests for the individual markers detected no significant isolation by distance. Neutrality tests were largely non-significant, but did not exclude recent expansion. The observed patterns are compatible with long-term establishment and secondary redistribution, but cannot distinguish this scenario from repeated introductions or other demographic histories. Because ND5 and CytB are linked and maternally inherited, these results describe maternal lineage structure and cannot establish contemporary gene flow or genome-wide population structure. This study provides the first nationwide mitochondrial baseline for M. matsumurae in South Korea, supporting future geographic comparisons and coordinated pest monitoring.