COI DNA barcoding to differentiate Haemagogus janthinomys and Haemagogus capricornii (Diptera: Culicidae) mosquitoes

The genus Haemagogus (Diptera: Culicidae) includes species that are important vectors of pathogens such as the yellow fever virus. The accurate identification of these species is essential for the control of zoonoses. Females of Hg. capricornii and Hg. janthinomys are morphologically indistinguishable, which makes the use of alternative identification techniques desirable. This study aimed to obtain sequences of the mitochondrial cytochrome c oxidase I (COI) gene, in the region widely used for DNA barcoding, of Haemagogus specimens from the state of São Paulo, Brazil, to evaluate the effectiveness of these sequences in the molecular identification of the species. A total of 37 female and 2 male mosquitoes were collected in various locations in the state of São Paulo, using methods such as hand-nets, Shannon traps, CDC light traps with CO₂ bait and Nasci aspirators. The sequences of a 710 bp fragment of the COI gene were amplified by PCR and sequenced. A phylogenetic tree reconstruction was conducted using the Bayesian approach implemented in MrBayes v3.2.2, providing support values for taxa where genetic clusters may indicate the presence of new or cryptic species. We obtained 39 COI sequences representing three species: Haemagogus capricornii, Haemagogus leucocelaenus, and Haemagogus janthinomys. Bayesian analysis of the sequences produced clades that corroborate the morphological identification of the species. The separation of Hg. capricornii and Hg. janthinomys received 100 % statistical support and the Hg. capricornii was very well supported (91 %). The two sequences from male specimens, morphologically identified as Hg. capricornii, were grouped in the same clade, a sister clade of Hg. janthinomys. It is important to highlight that the Hg. janthinomys were positioned in several subclades, showing a polymorphism of this species within the state, a situation not observed for Hg. capricornii. For the first time, sequences of the mtCOI gene from Hg. capricornii were obtained and related to morphologically identified specimens. COI sequences proved effective in the molecular identification of Haemagogus species. This study contributes to the expansion of the GenBank database, providing the first sequences of Hg. capricornii and new sequences for Hg. janthinomys and Hg. leucocelaenus.