Inter-specific and developmental differences on the array of antennal chemoreceptors in four species of Triatominae (Hemiptera : Reduviidae)

The aim of the work was to investigate the pattern of chemoreceptor sensill a in adults and fifth stage nymphs of Rhodnius prolixus, R. neglectus, Tria toma infestans and T. sordida in order to study, differences and similariti es between genera and species. Three types of sensilla were analyzed by lig ht microscopy: thin-walled a trichoidea, chick-walled trichoidea and busico nica. The number of sensilla of each three types were counted. The length o f the antennal segments were also used as a variable for the analysis. The statistical analysis showed that the number of these antennal chemoreceptor s had significant differences between species and between adults and nymphs of each species. Discriminant analysis separates incompletely the fifth st age nymphs of the four species and showed similarity between them. Discrimi nant analysis performed with 12 variables of the antennae, allowed a comple te separation of the adults of the four species.