An association is established between the Brazilian geographical pattern of the domiciliarity of the triatominae bugs and open lands characterized by natural savanna vegetation or artificial, man-made landscapes. The Brazilian open lands involved are the "caatingas'' and "cerrados", both wholly included in Brazilian territory, while the mixed Southern subtropical prairies belong to systems extending bevond national boundary lines. The other open lands are anthropic-lands opened mainly by the destruction of primitive forests of the tropical Atlantic system. Attempts were made to subject the four synanthropic species of epidemiological importance to model paleoecologic refuges and endemic centers. Triatoma sordida, Triatoma brasiliensis, and Triatoma pseudomaculata seem to have their endemic centers in the "cerrados" and "caatinga", while the Panstrongylus megistus may have originated in the tropical Atlantic forest system. The Triatoma infestans, however, seem to have originated in Bolivia, then were spread to large dispersal regions by man. Thus it can be assumed that domiciliarity is arrived at through an opportunistic mechanism stimulated by shelter and food availability factors. Once established, domiciliarity favors the species survival and dispersal, and this is of particular interest to control and surveillance programs because it increases the probability of the triatominae's success in synanthropic specialization. The present intense anthropic activities in the Amazonian system will lead to even greater expansion into the open lands; consequently, a triatominae domiciliarity spread can be expected, due to either autochthonous or man-introduced populations. A public health problem will then arise in a region where it has, heretofore, been unknown.
Trypanosomiasis; Triatominae domiciliation; Triatoma infestans; Triatoma sordida; Triatoma brasiliensis; Triatoma pseudomaculata; Panstrongylus megistus; Triatominae; Triatominae