Evolutionary insights from complete mitochondrial genomes of <i>Aedes albopictus</i> and <i>Culex pipiens molestus</i> (Diptera: Culicidae)

Mitochondrial genomes (mitogenomes) are powerful molecular tools for exploring phylogenetic relationships, deciphering adaptation and divergence, as well as disease transmission potential among insects. In this study, we performed a comparative mitogenomic and phylogenetic analysis of two major mosquito vectors - <i>Aedes albopictus</i> and <i>Culex pipiens molestus</i> - collected from South Korea, together with mitogenome data from 18 additional mosquito species representing three Culicidae genera (<i>Aedes</i>, <i>Anopheles</i>, and <i>Culex</i>) retrieved from GenBank. The assembled mitogenomes, each comprising 13 protein-coding genes, 22 tRNAs, and two rRNAs, revealed conserved gene order and structural features typical of Diptera. Comparative analyses with multiple species representing the three genera uncovered lineage-specific patterns in codon usage, base composition, and control region variability. Phylogenetic relationships inferred using maximum likelihood and Bayesian methods based on concatenated mitochondrial protein-coding genes robustly resolved genus-level relationships and supported the monophyly of the two major Culicidae clades, <i>Aedes</i> (tribe Aedini) and <i>Culex</i> (tribe Culicini), with <i>Anopheles sinensis</i> and <i>Anopheles gambiae</i> serving as outgroups. Time-calibrated Bayesian analyses indicated a deep divergence between <i>Anopheles</i> and the <i>Aedes-Culex</i> clade during the Paleogene (∼51.8 Mya), followed by the separation of <i>Aedes</i> and <i>Culex</i> around ∼39.7 Mya. Notably, <i>Ae. albopictus</i> diverged from its congeners ∼11.7 Mya, while <i>Cx. p. molestus</i> exhibited a much more recent divergence (∼2.35 Mya), suggesting distinct evolutionary pressures and histories. This study demonstrates the utility of mitogenomic data for reconstructing mosquito evolutionary history and provides insights relevant to vector biology, ecology, and public health.