Abstract. Here we apply inter-simple sequence repeat (ISSR) markers to explore the fine-scale genetic structure and dispersal in populations of Triatoma infestans. Five selected primers from 30 primers were used to amplify ISSRs by polymerase chain reaction. A total of 90 polymorphic bands were detected across 134 individuals captured from 11 peridomestic sites from the locality of San Martín (Capayán Department, Catamarca Province, Argentina). Significant levels of genetic differentiation suggest limited gene flow among sampling sites. Spatial autocorrelation analysis confirms that dispersal occurs on the scale of ∼469 m, suggesting that insecticide spraying should be extended at least within a radius of ∼500 m around the infested area. Moreover, Bayesian clustering algorithms indicated genetic exchange among different sites analyzed, supporting the hypothesis of an important role of peridomestic structures in the process of reinfestation.

Triatoma infestans (Hemiptera, Reduvidae) is the main vector of Chagas disease in South America between the latitudes 10° and 46° S. The analysis of the spatial genetic structure of populations at fine scale can provide insight into the dynamic population and evolutionary process of T. infestans and a complementary approach to help improve vector control strategies. Spatio‐temporal analysis of the genetic structure of T. infestans populations was performed using inter‐simple sequence repeats markers. A total of 242 polymorphic bands were detected from 234 individuals captured in different houses from the locality of San Martín and in one surrounding area (Capayan department, Catamarca province, Argentina) in October 2007 and May 2010. Significant levels of genetic differentiation were detected among the collection sites in both temporal samples, including the different sampled sites within the same house. These results confirm a high degree of subdivision in T. infestans populations. Comparative analysis between the first and the second sample indicated that they form two different groups. The genetic differentiation level was higher among samples from the second capture compared to the first. It is probable that in subdivided populations, when restricted gene flow is sustained over time, the genetic drift leads to accentuate the differentiation among subpopulations. The spatial autocorrelation analysis indicated that the dispersion range could occur around 500–550 m. Therefore, the probability of reinfestation by active dispersal of the insect could be reduced by implementing control and surveillance within an approximate radius of 500–550 m around the infested area.