ABSTRACT
Survival and molting incidence were studied after heat (40ºC) and cold (0ºC) shocks in specimens of Panstrongylus megistus with the aim of establishing its response to temperature stress under laboratory rearing conditions and to understand occasional changes in the biological characteristics of specimens captured in nature. The response to the thermal shocks was found to vary as a function of the temperature an duration of the shock, developmental phase and sex of the specimens, and in certain cases, the insect habit and nourishment conditions. P. megistus specimens were found to be less resistant to the heat shock assay than Triatoma infestans, another reduviid species. The short cold shock affected survival of P. megistus more than did the heat shock, survival of fully-nourished specimens being preferencial. The response of adults to the short cold shock was affected by sex, males being generally less resistant. The insect sylvatic habit was found to seldom affected the thermal shock response established for specimens with domestic habit. A decrease in molting frequency and sometimes a slowdown of the molting rate were found after the short heat and cold shocks, possibly promoted by changes in hormonal balance, and differing from patterns reported for T. infestans. The results indicate that no generalization should be made for different reduviid species in terms of the effects of temperature shocks.
Subject(s)
Animals , Panstrongylus/growth & development , Cold Temperature , Hot Temperature , Heat-Shock Response/physiology , SurvivorshipABSTRACT
A sobrevivência e a ocorrência de mudas em espécies de Triatoma infestans foram estudadas num período de 30 dias após choques de temperatura. Foi demonstrado que choques hipertérmico e hipotérmico interferem nesses processos, na dependência da temperatura do choque, tempo de sua duraçäo, fase de desenvolvimento e sexo dos espécimes. Dentre as situaçöes experimentais utilizadas, o choque a 0§C por 12 h pareceu produzir a açäo mais deletéria, porém choques a 40§C e 0§
Subject(s)
Animals , Male , Female , Temperature , Triatoma/growth & development , Larva/growth & developmentABSTRACT
Analisamos a fonte de alimentaçäo sangüínea de 94 triatomíneos (51 Triatoma brasiliensis, 42 T. pseudomaculata e um Rhodnius neglectus) da Fazenda Aroeira, no Município de Catolé di Rocha, no Estado da Paraíba, e de quatro localidades próximas. Observamos postividade para marsupial, homem e ave, respectivamente, de 39,7, 6,2 e 23,0 por cento. Três insetos da Fazenda Aroeira, positivos para Trypanosoma cruzi, foram positivos para marsupial, só um deles também para outro mamífero. Os marsupiais säo a mais importante fonte de T. cruzi para os insetos da área e estes têm pouco contato com o homem