Sylvatic and peridomestic populations of Triatoma pseudomaculata are not significantly structured by habitat, as revealed by two genetic markers

Abstract

Chagas disease remains a public health concern in Brazil and other Latin American countries, mainly due to the potential domiciliation of native triatomine species. We analyzed the genetic variability of Triatoma pseudomaculata in sylvatic and peridomestic ecotopes throughout three localities in the northeastern state of Bahia, Brazil. We studied polymorphisms generated by random amplified polymorphic DNA (RAPD) and isoenzyme electrophoresis analyses. Based on RAPD analysis, each specimen was assigned to one of three genetic clusters. Although all sylvatic specimens from one locality were grouped into the same cluster, sylvatic and peridomestic specimens from the other two localities were broadly distributed between the remaining two clusters, suggesting that geographic population structuring was not occurring. Furthermore, isoenzyme analysis suggested that distinct populations were in Hardy-Weinberg equilibrium. Low statistical values for Wright's Fst index also supported the absence of population structuring and suggested the occurrence of panmixia. We conclude that genetic flow occurs between sylvatic and peridomestic T. pseudomaculata populations, probably as a consequence of passive and active dispersion of the insects, associated with deforestation and anthropic transformations. Journal of Vector Ecology 35 (2): 295-300. 2010.

Triatoma maculata, the Vector of Trypanosoma cruzi, in Venezuela. Phenotypic and Genotypic Variability as Potential Indicator of Vector Displacement into the Domestic Habitat

“…The association with particular habitats or ecotopes of different phenotypical and genotypical characters in triatomines has proved important in vector identification, dispersion, and colonization properties and in general in the epidemiology and control of Chagas disease in South America (14, 37–39). …”

“…Different molecular strategies have been used to study genetic diversity in populations of triatomine vectors, such as variability of the mt Cyt b gene, microsatellites, and random amplified polymorphic DNA (RAPD) (14, 28, 37, 40). Previous studies on the genetic variability of T. maculata in Venezuela using mt Cyt b partially enabled to infer the occurrence of different haplotypes for populations in Anzoátegui and Portuguesa (4).…”

Mitochondrial PCR-RFLP Assay to DistinguishTriatoma brasiliensis macromelasomafromTriatoma brasiliensis brasiliensisSubspecies (Hemiptera: Reduviidae)

“…For instance, Triatoma maculata Erichson, 1848 and Triatoma pseudomaculata Corrêa & Espínola, 1964 which were first treated as members of a same species complex due to morphological similarities [5] thereafter proved to be genetically distant [17–19]. Panstrongylus herreri Wygodzinsky, 1948 and Panstrongylus lignarius Walker, 1873 in turn, were considered to be separate species until Marcilla et al [20] and Crossa et al [21] demonstrated that they are the same species, cytogenetically identical with regard to the second internal transcribed spacer.…”

Ecotope effect in Triatoma brasiliensis (Hemiptera: Reduviidae) suggests phenotypic plasticity rather than adaptation

“…Gene flow between ecotopes is also pervasive in other species, including Triatoma dimidiata (Dumonteil et al ., 2007), Triatoma vitticeps (Souza et al ., 2008), T. infestans (Marcet et al ., 2008) and Triatoma pseudomaculata (Carvalho‐Costa et al ., 2010). The selective hypothesis implies that certain shapes increase fitness enough to be associated with specific ecotopes within one or two generations, but few studies have evaluated this conjecture.…”