Pleistocene Climate Oscillations and Geographic Barriers Shaped the Phylogeographic Structure of <i>Anaplecta omei</i> (Blattodea, Blattoidea, Anaplectidae) in Southern China: Evidence From Mitochondrial Genomes

<i>Anaplecta omei</i> is the only species of <i>Anaplecta</i> widely distributed in southern China yet the processes shaping its genetic structure and range remain unclear. We used 97 complete mitochondrial genomes from 24 distinct geographic populations to characterize the genetic diversity, population structure, and evolutionary history of <i>A. omei</i>. Phylogenetic reconstruction, genetic diversity assessment, and population structure analysis revealed high haplotype diversity but low nucleotide diversity and a clear phylogeographic structure comprising four well-differentiated groups. Selection tests indicated no group-specific shifts in selective pressure, suggesting that physical barriers rather than adaptive divergence underlie this structure. Divergence-time estimates showed that interspecific splits among <i>Anaplecta</i> date to the Miocene, whereas major intraspecific divergences within <i>A. omei</i> occurred during the Pleistocene, and demographic analyses (neutrality tests, mismatch distributions, and Bayesian skyline plots) indicated that the divergence within <i>A. omei</i> was followed by late-Pleistocene population expansions in regional refugia. Together, these results indicate that tectonic uplift, Pleistocene climate oscillations, and complex topography have jointly shaped the phylogeographic diversification and distribution of <i>A. omei</i>, shedding light on diversification processes in Blattodea inhabiting montane landscapes.