Ciclo biológico em laboratório de Rhodnius brethesi Matta, 1919 (Hemiptera, Reduviidae, Triatominae), potencial vetor silvestre da doença de Chagas na Amazônia

Abstract

R. brethesi is a sylvatic species from the Amazon region; it has been incriminated as responsible for the transmission of Chagas disease in collectors of piacaba in this region. The aim of present study was to investigate the efficiency of these insects as potential vectors of Trypanosoma cruzi. Aspects related with feeding and defecation patterns, life time, and mortality had been observed in each instar of R. brethesi. We use 5th instar nymphs to get adults virgins, after the moulting 3 groups with 6 females and 2 males each were created to obtain eggs. After hatching, 1st instar nymphs had been weighed and kept in bottles until the next moult. Insects were fed once a week in mice. Results showed that the average period of incubation was 17 days, the number of blood meal was increasing from the 1st to the 5th instar nymph with 7 (average) to become adult, a significative numbers of the defecations occurring immediately after the bloodmeals. The total percentual of mortality was 16%. This results suggests that this species presents a good exploitation of blood meals and a brief nymphal development in laboratory conditions reflecting its behavior in sylvatic environments.

Biologia comparativa e comportamento alimentar de Rhodnius neglectus e Rhodnius robustus (Triatominae) sob condições de laboratório

“…Além da suscetibilidade aos parasitos, outras características dos triatomíneos como o comportamento alimentar (detecção da fonte alimentar, número de picadas, tempo de repasto, quantidade de sangue ingerido), e a frequência de dejeções também podem determinar a eficiência na transmissão do T. cruzi [15][16][17][18][19][20][21][22][23][24][25][26][27][28] …”

Avaliação em laboratório da atividade de voo de Rhodnius brethesi Matta, 1919, potencial vetor silvestre do Trypanosoma cruzi na Amazônia Brasileira. (Hemiptera:Reduviidae:Triatominae)

“…The small supply of hosts in its natural ecotope may have caused adaptations to the feeding behavior of R. brethesi, which has previously been observed feeding on 19 piassaba collectors during the day. Rocha et al studied the life cycle of the species in the laboratory and found that the insects were extremely efficient in using blood meals, with only one meal needed for ecdysis to the fifth nymph stage.…”

“…19 Rocha et al observed an average of seven blood meals during the adult stage of R. brethesi, which corresponds to approximately 50% of all flight attempts in the species. Weight loss measurements indicated that no individual initiated flight before losing at least 11.5% body weight.…”

Feeding and Defecation Patterns of Rhodnius nasutus (Hemiptera; Reduviidae), A Triatomine Native to an Area Endemic for Chagas Disease in the State of Ceará, Brazil

“…This data also indicates the capacity of the genus Rhodnius to be a vector for T. cruzi transmission, as has also been observed by other investigators. 23,[30][31][32] It was observed that of six triatomines species studied, 33 50% of R. prolixus specimens defecated during or soon after repast. The authors argued that on the basis of defecation behav-T able 2 Rates of defecation during and after feeding, and engorgement in different instars of Rhodnius nasutus , Ceará, Brazil* * CI = confidence interval.…”