DNA barcoding suggests new species for the Mansonia subgenus (Mansonia, Mansoniini, Culicidae, Diptera) in the area surrounding the Jirau hydroelectric dam, Porto Velho municipality, Rondônia state, Brazil.

Previous studies have linked the construction of hydroelectric dams with increases in the density of mosquitoes, especially Mansonia. In Brazil, Mansonia mosquitoes are still poorly studied at the taxonomic, biological, ecological and epidemiological levels, and nothing is known about the genetic diversity and the cryptic speciation of the group. The current study analyzed the molecular taxonomy of Mansonia species captured in the area surrounding the Jirau hydroelectric dam, Rondônia state, Brazil. Samples were collected from fifteen locations between 2018 and 2019. Genomic DNA of the specimens was extracted, and the DNA barcode region of the Cytochrome Oxidase, subunit I gene was amplified with PCR and both DNA strands were sequenced. The dataset was analyzed using MEGA, Mr. Bayes and DnaSP software. The results provided COI sequences for 100 specimens collected in the area surrounding from Jirau hydroelectric dam. These belonged to five species of the Mansonia subgenus, identified morphologically as Mansonia humeralis, Mansonia amazonensis, Mansonia titillans, Mansonia dyari and Mansonia indubitans. Findings showed that the COI gene is an effective and accessible DNA barcode that provides a high-resolution tool for delimiting species within the subgenus Mansonia, with the tree construction (Bayesian Inference) well supported and non-overlapping intraspecific and interspecific (K2-P) genetic distance values. These findings also indicate the occurrence of cryptic speciation within M. dyari and near of M. titillans. This is the first study to apply molecular tools to the taxonomy of Mansonia species from Brazil.

Diversity and spatio-temporal variation of Anopheles (Diptera: Culicidae) before and after the construction of the Jirau hydroelectric plant, state of Rondônia, Brazil

ABSTRACT The objective of this study was to evaluate the effect of the construction of the Jirau hydroelectric plant on the anopheline species, in Porto Velho, Rondônia, Brazil. For this, sampling was carried out in 23 locations in the pre (2004) and 23 after construction (2018) phases in the hydroelectric dam's coverage area, performed by human landing catch between 6:00 pm and 10:00 pm. We found 14 anopheline species. In the pre-construction phase, An. darlingi (73%) was the most abundant and after construction An. braziliensis (31.5%) was the most abundant. The T test indicated that there were no differences in the indexes - diversity (H '), richness (Sjack 1), equitability (J') and dominance (d) of anophelines species - evaluated between the phases (p > 0.05). The spatio-temporal distribution of An. darlingi proved to be wide, with the highest density values observed in March ( x ¯w = 27.1) in the pre-construction phase and in the months of May ( x ¯w = 4) and July ( x ¯w = 3.1), post-construction. Differences in hematophagic activity peaks were observed between species and between phases. According to the data obtained in this study, the construction of the hydroelectric plant had little influence on the composition of anopheline species, however changes were observed in the spatio-temporal distribution of the An. darlingi and in the pattern of hematophagic activity of the species, which directly influenced the dynamics of malaria in the region.