Genetic structure of Triatoma sordida (Hemiptera: Reduviidae) domestic populations from Bolivia: application on control interventions

The genetic population of Triatoma sordida group 1, a secondary vector of Chagas disease in Bolivia, was studied by multi-locus enzyme electrophoresis. A total of 253 nymphal and adult specimens collected from seven neighbouring localities in the Velasco Province, Department of Santa Cruz, were processed. The relatively low genetic variability was confirmed for this species (rate of polymorphism: 0.20). The absence of genetic disequilibrium detected within the seven localities was demonstrated. A geographical structuration appears between localities with distances greater than 20 km apart. Although T. sordida presents a relatively reduced dispersive capacity, its panmictic unit is wider than compared with T. infestans. Genetic distances between T. sordida populations were correlated with geographic distance. Gene flow between geographic populations of T. sordida provides an efficient framework for effective vigilance and control protocols.

Cryptic speciation in Triatoma sordida (Hemiptera:Reduviidae) from the Bolivian Chaco

Eight natural Bolivian populations of two closely related species of Triatominae, Triatoma sordida and T. guasayana, were analysed by multilocus enzyme electrophoresis at 20 loci. Both species were readily separated and no natural hybrid was observed. Among the silvatic sample of T. sordida, strong departure from panmixia within and between loci was detected in two sites of the Chaco, suggesting two reproductively separate populations easily recognized at Idh2 and Mdh2 loci. Genetic distance between them was in agreement with the hypothesis of distinct species. However, the detection of 3% of putative hybrids suggested a recent evolutionary divergence.