Uso de código de barras de DNA para estudo da fauna de flebotomíneos (diptera, psychodidae) no estado de Tocantins, Brasil

Abstract

Sandflies are insects belonging to the order Diptera, family Psychodidae, and subfamily Phlebotominae. Considered natural vectors of infectious agents, such as viruses, bacteria and protozoa, including Leishmania, which cause leishmaniasis in humans and other animals. About 1,003 species or subspecies are recognized, of which approximately 537 are present in the Americas, 277 of which are registered in Brazil. In the state of Tocantins (TO), so far, 70 species have been recorded, and of these, 32 occur in the District of Taquaruçu, municipality of Palmas. The studies carried out on the sand fly fauna and recorded of new species in the state of Tocantins, when only identification through morphological analysis was used. Considering the use of morphological data alone can underestimate or overestimate the number of species, the present work aims to carry out the molecular identification of sand fly species captured in the municipality of Palmas/TO, using the partial fragment of the cytochrome c gene subunit I oxidase (COI). Therefore, monthly collections were carried out during three consecutive nights, from January to June, at four sites: Cave Boa Esperança, Grotto’s Evilson, and Chácara Serra do Carmo and Chácara do Iago, with HP model light traps. Before processing the insects (clearing and mounting), the legs of each specimen were collected and frozen at -20°C for sequencing and subsequent molecular identification. The morphological identification of the specimens revealed 28 species distributed in 13 genera. Three species (Deanemyia samueli, Pintomyia gruta, Psathyromyia barretti), had not yet been registered in the state of Tocantins, thus, the sand fly fauna of the municipality and the state is composed, so far, of 35 and 73 species, respectively. Edentomyia sp. and Lutzomyia (Lutzomyia) sp., are probably still undescribed species, and new studies are needed to verify their real taxonomic identity. The use of DNA barcode proved to be efficient for identifying sand fly species in the state of Tocantins, and revealed the existence of cryptic diversity in three species, Nyssomyia whitmani, Psychodopygus sp. Chagasi series and Psathyromyia aragaoi, but the number of sequenced samples is a factor that influences the efficiency of the DNA Barcode technique. Thus, the present study encountered two obstacles with regard to the identification of species using COI sequences: the reduced number of samples analyzed for some species, as well as the lack of sequences deposited in GenBank.