Phenotypic variability associated to genomic changes in the main vector of Chagas disease in the southern cone of South America.

This study shows for the first time, the relationship between chromosomic and meristic quantitative characters of Triatoma infestans, the main vector of Chagas disease in the southern cone of South America. The antennal phenotype of 225 adults from five countries and three cytotypes, were analyzed using univariate and multivariate techniques. The study found a clear association between cytotypes and antennal phenotypes. The complexity of the antennal sensilla pattern was higher in the non-Andean cytotype, showing more chemoreceptors usually linked to sexual behaviour, host finding and flight. The phenetic differences were more notorious on females than on males. Changes in the sexual dimorphism were detected, being the differences most notorious in the non-Andean cytotype. Similitude of the geographic populations using the antennal phenotype coincides with environmental gradient of the area, showing a close association between the physical features of the living zones and quantitative traits of the vectors. The epidemiological implications of the phenetic differences observed in the study are discussed.