Laboratório de Parasitologia, Departamento de Ciências Biológicas, Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista "Júlio de Mesquita Filho", FCFAR/UNESP, Rodovia Araraquara-Jaú km 1, 14801-902 Araraquara, SP, Brazil; Instituto de Biociências, Universidade Estadual Paulista "Júlio de Mesquita Filho", IBB/UNESP, Rua Dr. Antônio Celso Wagner Zanin, 250, Distrito de Rubião Júnior, 18618-689 Botucatu, SP, Brazil. Electronic address: [Email]
Chagas disease is caused by the Trypanosoma cruzi and transmitted mainly by triatomines. Triatoma is a paraphyletic group and the species of this genus are grouped into complexes and subcomplexes. Morphological data and geographical distribution grouped initially T. melanocephala, T. vitticeps and T. tibiamaculata in the T. brasiliensis subcomplex. However, karyotypic and phylogenetic analysis suggested the exclusion of T. melanocephala, T. vitticeps and T. tibiamaculata from this subcomplex. Considering that studies of experimental crosses can help to understand the systematics of species, we performed experimental crosses between T. melanocephala, T. vitticeps and T. tibiamaculata with T. b. brasiliensis. No crosses resulted in hybrids. Taking into account that the species of the T. brasiliensis subcomplex do not present interspecific prezygotic barriers, the characterization of reproductive barriers shows that T. melanocephala, T. vitticeps and T. tibiamaculata do not present an evolutionary proximity relationship with the species of this subcomplex. Thus, we confirmed the exclusion of these species from the T. brasiliensis subcomplex and we emphasize the importance of experimental crosses for evolutionary studies.