The ecology of Triatoma sordida in natural environments in two different regions of the state of Minas Gerais, Brazil

Abstract

A study was undertaken about T. sordida in the natural environment in two different regions of the state of Minas Gerais: Itapagipe (Triângulo), an area of cerrado modified by the formation of fields of pasture and agriculture, and Mato Verde (north) an area of transition between caatinga and cerrado with profound deforestation in the last years due to the expansion of cotton cultivation. In both regions the principal ecotopes identified were hollow trees and the bark of live or dead trees, where the occurrence of a food source is not frequent. In this environment, the triatomines utilize various food sources; opposums appear to represent an important source of infection. In the north of Minas, a greater concentration of reservoirs and vectors was observed than in the Triángulo which could explain the higher level of infection of the triatomines in the north. Close attention to the process of domiciliation of T. sordida in the north of Minas is recommended where an extensive intervention by man in the natural environment has occurred and where a rise in the population of triatomines in the peridomestic environment has been observed in recent years.

Climatic factors influencing triatomine occurrence in Central-West Brazil

“…Both species are capable of adapting to different ecosystems, as has been noted by other authors (Lent & Wygodzinsky 1979, Forattini 1980, Gurgel-Gonçalves & Cuba 2009, Gurgel-Gonçalves et al 2011, 2012b. Although it is the most frequently encountered species in Brazil, T. sordida occurs mainly in peridomicile areas and generally feeds on birds, which reduces the probability of vectorial transmission of T. cruzi to humans (Diotaiuti et al 1993). R. neglectus frequently inhabits palm trees in CW (Barretto et al 1969, Gurgel-Gonçalves et al 2004, AbadFranch et al 2009, Gurgel-Gonçalves & Cuba 2009, where it participates actively in the enzootic transmission of T. cruzi and Trypanosoma rangeli (Gurgel-Gonçalves et al 2012a); this species has been documented in domiciliary environments in recent years (Oliveira & Silva 2007, Almeida et al 2008, which may be related to ecological processes that stimulate the invasion of artificial ecotopes by potentially infected individuals (Abad-Franch et al 2009).…”

Occurrence of synanthropic triatomines (Hemiptera: Reduviidae) in the Federal District of Brazil

“…Regardless of the fact that it has remained the most collected species in cerrado areas of Brazil for the past years 18,[45][46][47] , T. sordida presents a low risk of transmission of T. cruzi to humans because of its peridomiciliary behavior and marked ornithophily 15,34,[46][47] . Some studies show that zones of higher occurrence of T. sordida correspond to those of higher and older farm exploration 33 , which may justify the higher frequency of this species in Planaltina.…”

Controle do Triatoma sordida no peridomicílio rural do município de Porteirinha, Minas Gerais, Brasil

“…Este fluxo de insetos parece ocorrer em ambas as direções, tanto do peridomicílio para o ambiente silvestre, como do ambiente silvestre para o peridomicílio. A grande proporção de adultos capturados em maio de 1994 (49,4% do total de insetos capturados) confirma na região a existência de um pico imaginal no final do primeiro semestre do ano, conforme verificado em outras áreas (13,14), e a existência de apenas um ciclo anual do T. sordida.…”