DNA barcoding and mitochondrial genetic diversity of mosquito vectors from central India

Accurate discrimination of mosquito vectors is essential for entomological surveillance in India, where multiple Anopheles, Aedes and Culex species transmit malaria, lymphatic filariasis and arboviral diseases. However, routine species identifications are challenged by cryptic and morphologically similar taxa. Furthermore, population genetic information of major mosquito vectors remains elusive.

A total of 265 adult mosquitoes representing 21 species from four mosquito genera and one non-mosquito dipteran genus ( Chironomus ) used as an outgroup, were collected from indoor and outdoor resting habitats in selected districts of Madhya Pradesh and Chhattisgarh. Mosquitoes were identified morphologically using standard keys and a mobile identification application. Subsets of specimens representing major genera and putative vector and non-vector taxa were subjected to PCR amplification and sequencing of the cox1 and ITS2 genes that are known to be genetic barcodes for mosquitoes. DNA sequences of these two genes were analyzed for inter- and intra-specific divergence, and phylogenetic clustering and genetic diversity.

The cox1 marker showed 100% amplification success and reliably separated most species and genera, although it failed to fully resolve certain closely related taxa, particularly within Anopheles and culicine groups. In contrast, ITS2 amplification success was lower (~50%) but provided complementary resolution for selected species complexes that clarified ambiguous morphological assignments and improved discrimination of selected species complexes in combination with cox1 . Phylogenetic analyses recovered largely congruent species-level clustering across both markers, highlighting both the strengths and limitations of each marker for operational surveillance. Furthermore, mitochondrial diversity analyses revealed high haplotype diversity in Anopheles species with limited genetic differentiation between populations, suggesting weak population structure.

The combined use of morphology with cox1 and ITS2 sequencing enhances species identification and phylogenetic resolution in diverse mosquito vectors. While cox1 serves as a robust primary barcode for routine surveillance, ITS2 provides additional resolution for cryptic taxa., However, population genetic inferences based on mitochondrial data alone should be interpreted cautiously. These findings support the strengthening of molecularly informed vector surveillance pipelines and backup more precise, evidence-based vector control in endemic settings.