Isoenzymes detect variation in population of Triatoma brasiliensis (Hemiptera: Reduviidae: Triatominae)

RESUMO

Triatoma brasiliens is one of the most important vectors of Chagas diseases in the semiarid zone of the northeast of Brazil. Intraspecific morphological and behavioural variation has been reported for different populations. Results for four distinct populations using eight isoenzymes are reported here. The literature descibes three subspecies T. brasiliensis Neiva, 1991; T. brasiliensis melanica Neiva & Lent, 1941 and T. brasiliensis macromelasoma Galvao, 1956. These subspecies differ mainly in their cuticle colour pattern and were regarded as synonyms by Lent and Wygodzinsky (1979). In order to evaluate whether the chromatic pattern is a morphological variation of different melanic forms within T. brasiliensis or due to interspecific variation, field collections were performed in localities where these three subspecies have been described Caico (Rio Grande do Norte), the type-locality for T. b. brasileiensis; Petrolina (Pernambuco) for T. B. macromelasoma and Espinosa (Minas Gerais) for T. b. melanica. A fourth distinct chromatic pattern was found in Juazeiro (Bahia). A total of nine loci were studied. Values of Nei's genetic distance (D) were calculated. T. b. brasiliensis and T. b. macromelasoma are the closest populations with a D=0.295. T. b. melanica had a Dò0.537 when compared to the others, a distance in ther range of interspecific variation for other triatomine species.