Abstract
This study analyzed the body and the operculum of eggs of Triatoma rubrovaria, T. carcavalloi and T. circummaculata, considered sylvatic species that live in sympatry.Triatoma rubrovaria is currently considered the most important vector of Trypanosoma cruzi in the rural areas of the state of Rio Grande do Sul, followed by T.circummaculata. Significant differences other than morphometry have been observed in the egg structures of the three species using traditional microscopy and scanning electron microscopy. Triatoma circummaculata eggs are smaller than those of T.rubrovaria and T. carcavalloi. The average number of perforations in corionic cells in the egg body is higher for the T. rubrovaria. The average number of perforations in the operculum cell is higher in T. circummaculata. This is the first morpho-structural description of T. carcavalloi eggs. These results widen the concept of these three species and create new subsidies for the entomological monitoring in areas in which these vectors may infest human living quarters.