Spatial distribution of Triatominae populations (Hemiptera: Reduviidae) in Mauritia flexuosa palm trees in Federal District of Brazil

摘要

To determine and analyze the distribution of Triatominae sylvatic populations in the Federal District of Brazil, 150 Mauritia flexuosa palm trees were sampled in six veredas of different landscapes (sylvatic, rural and peri-urban) in the rainy season. Triatomines were morphologically identified and grouped by sex and nymphal stage and were examined to verify infection by Trypanosoma cruzi and Trypanosoma rangeli. Twenty eight (18.6%) palm trees were infested by Rhodnius neglectus and fourteen (9.5%) by Psammolestes tertius. The frequency of Triatominae in palm trees with and without nests was significantly different being higher in palm trees with bird and mammal nests in the crown. The higher average number of insects/palm tree was observed in rural areas with estimates of up to 838 insects/hectare. The species age makeup presented a different pattern, with nymphs predominant for Rhodnius neglectus and adults predominant for Psammolestes tertius. Also, many Rhodnius neglectus eggs were collected, which indicates a reproductive event in February 2003. Among the nests found in palm trees, that of the Phacellodomus ruber (Furnariidae) bird had the greatest abundance of Triatominae, occurring on 42% of palm trees. The relative abundance of Rhodnius neglectus and Psammolestes tertius was greater in rural areas which contained higher number of nests in palm trees and lesser density of palms per hectare. None of the 96 triatomines examined were infected by Trypanosoma cruzi or Trypanosoma rangeli, despite our finding of Rhodnius neglectus infection by those parasites in former studies.