Sôbre a dispersão do Triatoma infestans

Abstract

Foram reunidas as informações disponíveis sôbre a dispersão do T. infestans noNão é um fenômeno raro a dispersão das espécies invasoras se processar primei ramente de forma contínua até ocupar completamente determinada região, adian te da qual elas só conseguem se estabele cer em pequenas áreas isoladas. Três exemplos dêsse tipo de distribuição estão representados em mapas transcritos no li vro de Elton, em 1958 (12), hoje clássico, sôbre a ecologia das invasões, e com res peito a um dêles, o do fungo Eudothia parasitica, o autor informa que diversas in fecções isoladas foram erradicadas.É, também, um fato relativamente co mum os animais mudarem de nicho quan do encontram um outro desocupado, es tando nesse caso tôdas as espécies ruderais que, certamente, são mais antigas que o homem.Com base nessas idéias é que será feito o presente estudo sôbre a dispersão do T. infestans.

Lack of Segregation between Two Species of Chagas Disease Vectors

“…A drastic decrease in T. infestans detection inside households led to a concomitant increase in the number of P. megistus captured at these ecotopes. 5 These epidemiologic data indicate that P. megistus competed at a disadvantage with T. infestans and suggest that T. infestans was better adapted to domiciliary ecotopes than P. megistus.…”

“…[2][3][4] Triatoma infestans was apparently introduced in Brazil by human migration and it only occupies peridomiciliary and intradomiciliary ecotopes in this country. 5 Because of high densities of domiciliary infestation and prevalence of Chagas disease associated with this species, T. infestans was considered the most important triatomine vector in Brazil, although it is not autochthonous. With the expansion of the Vectorial Control Program implemented by the Supervision of Health Campaigns, Ministry of Health, Brasilia, Brazil, in the early 1980s, this species was then eliminated from vast areas of the country.…”

“…27 Dias 18 reported that during 1943-1953, 877 domiciles with mixed infestations of P. megistus and T. infestans were identified in Brazil. Thus, the spatial isolation observed for these species 5,7,[20][21][22][23]49 is probably caused by competition processes. 5,24,26,50 Differences in dispersal rates may represent an additional dimension that could interfere in the house infestation capacity of these species.…”

“…Thus, the spatial isolation observed for these species 5,7,[20][21][22][23]49 is probably caused by competition processes. 5,24,26,50 Differences in dispersal rates may represent an additional dimension that could interfere in the house infestation capacity of these species. Although T. infestans and P. megistus are known to promptly initiate flight, 51,52 further studies would be necessary to analyze whether differences in flight capacity between them could be related to distinct dispersal rates and spatial distribution.…”

Changes in nuclear phenotype frequencies following sequential cold shocks in Triatoma infestans (Hemiptera, Reduviidae)

“…Indeed, in terms of insect survival, T. infestans is tolerant to single or sequential shocks at 0ºC, regardless of the nutritional state of the specimens, whereas in terms of molting rate, fasting elicits a protective action, in addition to that induced by cold shocks (Campos et al 2002). Since the specimens of T. infestans analyzed here originated from insects collected in the State of São Paulo and south of the Minas Gerais, their source is concerned with the hypothesis of the species coming from Argentina (Aragão 1971, Silva 1986, Monteiro et al 1999. According to Noireau and his co-workers (2000), domestic populations of T. infestans from Brazil and Argentina differ from the sylvatic populations of this species occurring in the Andean valleys of Bolivia.…”