Wing Geometric Morphometrics as a Tool for the Identification of Culex Subgenus Mosquitoes of Culex (Diptera: Culicidae)

SIMPLE SUMMARY: Different mosquito species have different ecology and behaviors. Therefore, the correct identification of vector mosquito species is essential for the development of targeted mosquito control operations. Traditionally, the identification of mosquitoes to species relies on differences in their external morphological characters. Identifying mosquitoes can be challenging if the specimen is either damaged or if only a few morphological characters can be used to sort them apart. For this reason, this study focused on the use of wing geometric morphometrics to identify Culex species from the subgenus Culex that are not easily identified by their external morphology. We analyzed the wing shape variation of 11 different species. Our results indicated that the species in this study were identified with high degrees of confidence based on their wing shape variation. From all possible comparisons in the cross-validated reclassification test, 87 yielded values higher than 70%, with 13 comparisons yielding 100% reclassification scores. Overall, our results are suggesting that wing geometric morphometrics is a reliable tool to identify Culex species of the subgenus Culex. ABSTRACT: Culex is the largest subgenus within the genus Culex that includes important vectors of diseases. The correct identification of mosquitoes is critical for effective control strategies. Wing geometric morphometrics (WGM) has been used to identify mosquito species alongside traditional identification methods. Here, WGM was used for eleven Culex species from São Paulo, Brazil, and one from Esquel, Argentina. Adult mosquitoes were collected using CDC (Centers for Disease Control) traps, morphologically identified and analyzed by WGM. The canonical variate analysis (CVA) was performed and a Neighbor-joining (NJ) tree was constructed to illustrate the patterns of species segregation. A cross-validated reclassification test was also carried out. From 110 comparisons in the cross-validated reclassification test, 87 yielded values higher than 70%, with 13 comparisons yielding 100% reclassification scores. Culex quinquefasciatus yielded the highest reclassification scores among the analyzed species, corroborating with the results obtained by the CVA, in which Cx. quinquefasciatus was the most distinct species. The high values obtained at the cross-validated reclassification test and in the NJ analysis as well as the segregation observed at the CVA made it possible to distinguish among Culex species with high degrees of confidence, suggesting that WGM is a reliable tool to identify Culex species of the subgenus Culex.