The objective of this study was to evaluate the feeding behavior of Triatoma vitticeps through the identification of its food sources and the characterization of the blood ingestion process. In addition, we aimed to verify if the saliva of this vector interferes with the perception of the host during the feedings by creating a nervous impulse. Here, we demonstrated that the T. vitticeps saliva reduces, gradually and irreversibly, the amplitude of the compound action potential of the nervous fibre, which helps decrease the perception of the insect by the host. The precipitin reaction demonstrated the feeding eclecticism of this vector, with the identification of eight food sources - most of them found simultaneously in the same insect. The analysis of the electrical signals produced by the cibarial pump during meals demonstrated that the best feeding performance of T. vitticeps nymphs that fed on pigeons is mainly due to the higher contraction frequency of the pump. The longer contact period with the host to obtain a complete meal compared with other triatominae species of the same instar could favor the occurrence of multiple blood sources in T. vitticeps under natural conditions, as it was evidenced by the precipitin test.

Our hypothesis is that the action of aggregating and disaggregating substances in the blood can be detected and quantified by the Microplate Reader. To ascertain the validity of this hypothesis, we selected two types of blood: one that naturally presents erythrocyte aggregation (pig blood) and the other that does not present aggregation (bovine blood). One important reason for the choice of pig blood is that its erythrocyte aggregation resembles that of human blood. T. infestans saliva was added to the pig blood as a disaggregating substance, while bovine fibrinogen was added to the bovine blood as a substance that promotes erythrocyte aggregation. We investigated the dynamic viscosity (h) of these mammals' blood, of T. infestans saliva and of the absorption (A) by Microplate Reader, carrying out UV-Vis spectrophotometric assays of pig plasma with different concentrations of triatominae saliva and of bovine blood with different concentrations of fibrinogen. Our findings indicate that spectroscopic techniques such as the Microplate Reader complement and expand the study of blood rheology, erythrocyte sedimentation and aggregation.

Foram estudados alguns parâmetros biológicos e fisiológicos do Triatoma brasiliensis em comparação com o Triatoma infestans e com o Triatoma pseudomaculata. O T. brasiliensis, alimentado em camundongos, apresentou um ciclo evolutivo de ninfa de primeiro estádio a adulto mais rápido e uma fecundidade maior quando comparado às demais espécies. O T. infestans apresentou a maior velocidade de ingestão sangüínea nos dois hospedeiros testados, seguido pelo T. brasiliensis e pelo T. pseudomaculata. Os testes de coagulação nos quais foram utilizados extratos de glândulas salivares de T. brasiliensis apresentaram valores de atividade anticoagulante intermediários entre os de T. infestans e os de T. pseudomaculata.

Biological and physiological parameters of Triatoma brasiliensis, Triatoma infestans, and Triatoma pseudomaculata were studied and compared. T. brasiliensis, reared on mice, showed a faster evolutionary cycle from first stage to adult and higher fecundity, when compared to the other species. T. infestans showed the fastest blood intake in both hosts tested, followed by T. brasiliensis and T. pseudomaculata. Clotting tests using salivary gland extracts of T. brasiliensis presented intermediary values of anti-clotting activity when compared to T. infestans and T. pseudomaculata.

Foram estudados alguns parâmetros biológicos e fisiológicos do Triatoma brasiliensis em comparação com o Triatoma infestans e com o Triatoma pseudomaculata. O T. brasiliensis, alimentado em camundongos, apresentou um ciclo evolutivo de ninfa de primeiro estádio a adulto mais rápido e uma fecundidade maior quando comparado às demais espécies. O T. infestans apresentou a maior velocidade de ingestão sangüínea nos dois hospedeiros testados, seguido pelo T. brasiliensis e pelo T. pseudomaculata. Os testes de coagulação nos quais foram utilizados extratos de glândulas salivares de T. brasiliensis apresentaram valores de atividade anticoagulante intermediários entre os de T. infestans e os de T. pseudomaculata.

Biological and physiological parameters of Triatoma brasiliensis, Triatoma infestans, and Triatoma pseudomaculata were studied and compared. T. brasiliensis, reared on mice, showed a faster evolutionary cycle from first stage to adult and higher fecundity, when compared to the other species. T. infestans showed the fastest blood intake in both hosts tested, followed by T. brasiliensis and T. pseudomaculata. Clotting tests using salivary gland extracts of T. brasiliensis presented intermediary values of anti-clotting activity when compared to T. infestans and T. pseudomaculata.