ISOENZYMES DETECT VARIATION IN POPULATIONS OF TRIATOMA-BRASILIENSIS (HEMIPTERA, REDUVIIDAE, TRIATOMINAE)

Triatoma brasiliensis is one of the most important vectors of Chagas d isease in the semiarid zone Of the northeast of Brazil. Intraspecific morphological and behavioural variation has been reported for differen t populations. Results for four distinct populations using eight isoen zymes are reported here. The literature describes three subspecies. T. brasiliensis brasiliensis Neiva, 1911; T. brasiliensis melanica Neiva & Lent, 1941 and T. brasiliensis macromelasoma Galvao, 1956. These su bspecies differ mainly in their cuticle colour pattern and were regard ed as synonyms by Lent and Wygodzinsky (1979). In order to evaluate wh ether the chromatic pattern is a morphological variation of different melanic forms within T. brasiliensis oi doe to interspecific variation , field collections were performed in localities where these thr-ee su bspecies hate been described: Caico (Rio Grande do Norte), the type-lo cality for T. b. brasiliensis; Petrolina (Pernambuco) for T. b. macrom elasoma and Espinosa (Minas Gerais) for T. b. melanica. A fourth disti nct chromatic pattern was found in Juazeiro (Bahia). A total of nine l oci were studied. Values of Nei's genetic distance (D) were calculated . T. b. brasiliensis and T. b. macromelasoma are the closest populatio ns with a D=0.295. T.b. melanica had a D greater than or equal to 0.53 7 when compared to the others, a distance in the range of interspecifi c variation for other triatomine species.