Genetic structure of four species of Triatoma (Hemiptera: Reduviidae) from Argentina.

The genetic structure of Triatoma guasayana Wygodzinsky & Abalos, T. sordida (Stål), T. platensis Neiva, and T. infestans (Klug) was compared by starch gel electrophoresis. In total, 17 enzyme loci were analyzed in T. infestans and 14 loci in the other three species. Zymograms were useful in species identification. Icdh-2 and Hk-1 are diagnostic loci, and Icdh-1, Hk-2, Es-1, and Es-2 are helpful in distinguishing these species. The proportion of polymorphic loci for the four species (range, 52.9 to 58.3%) was somewhat higher than that expected from reports for other insects. Mean heterozygosity per locus (range, 0.062 to 0.156) was within the range reported for insects in the literature. The level of heterozygosity was highest for T. guasayana and lowest for T. sordida. Values of genetic distance (Nei's D), identity (Nei's I), and similarity (Rogers's S) indices indicate that the four species are well-defined taxa. T. infestans and T. platensis are the closest (D = 0.45, S = 0.62). T. guasayana and T. sordida (D = 0.77, S = 0.46) form another pair of related species.