Genetic data support speciation between Panstrongylus howardi and Panstrongylus chinai, vectors of Chagas disease in Ecuador

Abstract

Limited genetic data are currently available for three vectors of Chagas disease in Ecuador, Panstrongylus howardi, P. chinai, and P. rufotuberculatus. Previously regarded as mainly sylvatic, these species have been poorly studied. Recently, they have been more frequently reported in domiciles and peridomiciles and are now considered true secondary vectors of Chagas disease in a country where an estimated 200,000 people are infected by Trypanosoma cruzi, a causative agent of this disease.In order to fill this gap, we obtained DNA for sequencing from 53 insects belonging to these three species and mainly sampled from the two Ecuadorian provinces of Loja and Manabí. We used six mitochondrial loci (COI, COII, ND4, CytB, 16S, and 12S) and two nuclear ones (ITS2 and 18S). We interpreted the phylogenetic trees built with single and concatenated data through maximum likelihood, Bayesian Markov chain Monte Carlo, and maximum parsimony methods.We provide evidence that P. chinai and P. howardi are indeed two supported species closely related and derived from a common ancestor. Additionally, the phylogenetic position of P. rufotuberculatus was confirmed as being distant from P. chinai and P. howardi and clustered with Triatoma dimidiata, a species belonging to the Northern American Triatoma clade.