Experimental evidence for a demographic cline in Panstrongylus megistus populations

Abstract

The population biology of three populations of Panstrongylus megistus was compared to determine possible influence on the behaviour and epidemiological importance of this species. The results demonstrated differences in terms of egg eclosion time, nymphal mortality and development rates, and feeding and defaecation rates. These differences appeared to follow a geographical cline, primarily reflecting different degrees of adaptation to domestic habitats.

Phenetic analysis of Panstrongylus megistus Burmeister, 1835 (Hemiptera: Reduviidae: Triatominae) in the State of Paraná-Brazil

“…However, the natural population from Minas Gerais grouped with both populations from Paraná (Lpm3), and that from Rio Grande do Sul grouped with that from Sergipe and all three from Paraná (Lpm4). The P. megistus population from Minas Gerais was isolated from that from Santa Catarina had been previously also observed by other authors (Barbosa et al, 1999(Barbosa et al, , 2001. However, the grouping of the populations from Rio Grande do Sul with that from Sergipe and some from Paraná demonstrated the existence of sister-populations separated by vast geographic expanses.…”

“…A genetic distance of 0.08 and similarity above 90% were found, reinforcing the hypothesis of identical populations standing out in different geographical regions, and different populations in one and the same region (Carpintero et al, 2003). This was also observed in a study carried out on P. megistus samples from Pernambuco, Bahia, and Rio de Janeiro with 15 isoenzymatic systems in which no isoenzymatic difference among the three populations was found (Barbosa et al, 2001). Panstrongylus megistus is considered a triatomine bug coming from forested and humid regions, owing its dispersion to the adverse conditions of temperature and humidity (Foratini, 1980, Foratini et al, 1977, 1984; the anthropic action would also afford such condition.…”

Lack of Segregation between Two Species of Chagas Disease Vectors

“…9,10 Studies on population diversity of P. megistus in different regions in Brazil reported distinct degrees of adaptation to domestic habitats. [11][12][13][14][15] In northeastern states such as Bahia, P. megistus is well adapted to domestic habitats, but its presence in sylvatic foci has not been proven. 11,12 However, in southeastern states, it can be found in sylvatic and domestic habitats.…”

Análise das relações taxonômicas e sistemáticas entre espécies de triatomíneos (Hemiptera: Reduviidae) de colônias mantidas pelo Serviço Especial de Saúde de Araraquara, inferida de seqüências de genes mitocondriais

“…Há também hematofagia facultativa em outros hemípteros como Physoderinae CARVAVALLO et al, 2000). Além disso, como exposto anteriormente, existem exceções também em triatomíneos quanto ao hematofagismo, caso da cleptohematofia e da hemolinfagia observadas principalmente em ninfas de algumas espécies (NEIVA, 1914;COSTA LIMA, 1940, ABALOS e WYGODZINSKY, 1951RYCKMAN, 1951;RABINOVICH, 1972;LENT e WYGODZINSKY, 1979;MILES, 1981;LOROSA, 2000;SANDOVAL, 2000;BARBOSA et al, 2001;RUAS-NETO, 2001). …”

“…Porém, várias espécies, principalmente ninfas jovens, foram observadas alimentando-se da hemolinfa de outros artrópodes (hemolinfagia) ou ainda, praticando uma forma de "pseudocanibalismo" conhecida por cleptohemodeipnonismo ou cleptohematofagismo. Neste aspecto, os triatomíneos são muito resistentes ao jejum o que, para muitos autores, é um aspecto relativo às populações K-estrategistas (NEIVA, 1914, COSTA LIMA, 1940BRUMPT, 1941;ABALOS e WYGODZINSKY, 1951;RYCKMAN, 1951;RABINOVICH, 1972, BARRETO, 1976, 1979LENT e WYGODZINSKY, 1979;MILES, 1981;JURBERG e LOROSA, 1999;LOROSA, 2000;SANDOVAL, 2000;BARBOSA et al, 2001;RUAS-NETO, 2001;CERETTI JUNIOR, 2003).…”