Filogeografia de Panstrongylus Megistus (burmeister, 1835) (hemiptera, Reduviidae, Triatominae)

Abstract

Chagas disease is considered one of the negleted tropical diseases of Latin America and its etiological agent is Trypanosoma cruzi, transmitted by hematophagous bugs, known as kissing bugs, which belong to the subfamily Triatominae. Within this dubfamily, there is Panstrongylus megistus, one of the main vectors of Chagas disease in Brazil. Its epidemiological importance for Chagas disease is due to its high domiciliation capacity, commonly found in domestic environments. However, its domiciliation capacity is different between regions, because in some areas, this species is considered sylvatic. One of the possibilities to explain this fact is phylogeography, which is the study of the processes that influence geographical distribution of genealogical lineages. Thereby, based on the phylogeographical patterns of Panstrongylus megistus, this thesis aims to correlate the different domiciliation capacities of P. megistus populations. The phylogeographyc analyses was based on fragments of the mitochondrial gene Cytochrome b (Cytb) and ribosomal DNA intergenic region (rDNA), comprising complete internal transcribed spacer (ITS)-1, 5.8S, and ITS-2 sequences. 16 sequences of cytb and 26 sequences of rDNA, from different populations, were analysed. All the sequences were obtained from GenBank. Phylogenetic analyses of Bayesian Inference, haplotype diversity, haplotype network, AMOVA, Fst analysis and Mantel test were performed. The analyses showed poor genetic structure associated to geographical distribution of the populations. Besides, the analyses showed poor diversity and genetic variance between populations, which suggests a recent population expansion from na ancestral population, originated in the Atlantic Forest. Active and passive dispersion explains the specie`s wide geographical distribution in Brazil, which led some populations to spread to regions with different environmental conditions. Thereby, some populations found in the domiciles, favourable microclimatic conditions and food source, which favoured the adaptation of these populations to the domiciles, becoming isolated from other sylvatic populations. Deforastation caused by human activities has also played na import role on the domiciliation of some populations, because of the destruction of natural ecotopes and reduction of food sources. Future research with bigger number of populations analysed and molecular markers can present more complete and resolved information regarding phylogeographical patterns of P. megistus