Molecular phylogeography of the Amazonian Chagas disease vectors Rhodnius prolixus and R. robustus

Abstract

The phylogeographical structure of the closely related species Rhodnius prolixus and R. robustus is presented based on a 663-base pair (bp) fragment of the mitochondrial cytochrome b gene. Twenty haplotypes were recovered from 84 samples examined, representing 26 populations from seven Latin American countries. The resulting phylogenetic tree is composed of five major reciprocally monophyletic clades, one representing R. prolixus and four representing R. robustus. While R. prolixus is a very homogeneous assemblage, R. robustus has deeper clades and is paraphyletic, with the clade comprising R. robustus from Venezuela (Orinoco region) more closely related to the R. prolixus clade than to the other R. robustus populations from the Amazon region. The R. robustus paraphyly was supported further by the analysis of a nuclear gene (D2 region of the 28S RNA) for a subset of specimens. The data support the view that R. robustus represents a species complex. Levels of sequence divergence between clades within each region are compatible with a Pleistocene origin. Nucleotide diversity (pi) for all R. prolixus populations was extremely low (0.0008), suggesting that this species went through a recent bottleneck, and was subsequently dispersed by man.

Molecular genetics: Bloodthirsty amazons?

“…Using sequence data from the mitochondrial cytochrome oxidase subunit I from 19 sites throughout Latin America, they observed a pronounced differentiation between samples from south and central America. Similar patterns have been observed in the Rhodnius (Triatominae) vectors of Chagas disease, where the pattern was thought to be a result of vicariance events within the Pliocene (B2.4-3.7 My) (Monteiro et al, 2003). Within the South American group of A. darlingi there were two further clusters termed northern Amazon and south America, which may well be important for the dating of Pleistocene events.…”

The triatominae species of French Guiana (Heteroptera: Reduviidae)

“…Recent studies in molecular biology and phylogeography (Monteiro et al 2003, Pavan & Monteiro 2007 show that the Guyana Shield is located out of the distribution area of R. prolixus. According to these studies, the species is present north of the Amazonian Basin, in Central America and in the non-Amazonian zone of Colombia and Venezuela.…”

Estructura poblacional y variabilidad genética de Rhodnius prolixus (Hemiptera: Reduviidae) procedente de diferentes áreas geográficas de Colombia

“…Los resultados obtenidos por la técnica de RAPD para las poblaciones domiciliadas concuerdan con lo reportado en estudios anteriores realizados por morfometría y patrones isoenzimáticos, en los cuales se demuestra que aunque R. prolixus presenta baja variabilidad genética, se observan algunas diferencias significativas entre poblaciones locales y otras variantes geográficas (25)(26)(27)(28); otros estudios realizados por medio de análisis de secuencias de ADN mitocondrial y ADN nuclear reportan resultados similares a los obtenidos por medio de las otras técnicas, mostrando que R. prolixus es una especie muy homogénea genéticamente (29)(30)(31)(32); sin embargo en ninguno de estos estudios se incluyen las poblaciones silvestres colombianas recientemente reportadas e incluidas en el presente estudio, razón por la cual encontramos una variabilidad genética moderada entre las poblaciones silvestres y las domiciliadas.…”