Spatial structuring of Triatoma infestans (Hemiptera, Reduviidae) populations from northwestern Argentina using wing geometric morphometry.

Wing geometric morphometry was used to study the spatial structuring of populations of Triatoma infestans from different villages, ecotopes, and sites within a village in northwestern Argentina. A total of 308 male and 197 female wings of T. infestans collected from peridomestic and domestic ecotopes in March 2000 was analyzed. On average, female bugs had a significantly larger wing size than males. Triatomines collected from domiciles or structures associated with chickens had larger wings than bugs collected from goat or pig corrals. The wing size of bugs did not differ significantly between villages. Discriminant analyses of wing shape showed significant divergence between villages, ecotopes, and individual collection sites. The study of metric variation of males between sites belonging to the same ecotope also revealed significant heterogeneity. Indeed, within the same section of the village the difference between two goat corrals was sometimes greater than that between neighboring goat and pig corrals. Thus, morphometric heterogeneity within villages may be the result not only of ecotope and host associations, but also of physical isolation between subunits. The strong structuring of T. infestans populations in the study area indicates that recolonization could be traced back to a small geographic source.