Resumen

BAR, María Esther. Population structure of Triatoma sordida Stål 1859 collected in a community of Butia yatay in Argentina. Bol Mal Salud Amb [online]. 2006, vol.46, n.1, pp.21-29. ISSN 1690-4648.

The population structure of Triatoma sordida in the palm Butia yatay, and its relative abundance during 1 year was studied in Colonia Laurel, Departamento San Roque, Corrientes, Argentina (28° 28’ S; 58° 26’ W). Samples were collected in the spring of 1998 and the summer, autumn and winter of 1999. Fifty-five palms were examined, and the predominance of T. sordida (N = 423) was confirmed in relation to the reduced number of T. platensis and Psamolestes coreodes captured. It is the first citation in Argentina of the presence of T. sordida in this species of palm. The relative abundance of T. sordida shows a marked seasonality. In spring, the total of individuals collected tripled those found in the remaining seasons, and the relative abundance oscillated between 57 and 88 individuals per month, coinciding with the reproductive period of the species. All the nymphal stages were present, with a predominance of NIII, NIV and NV. Of the total population collected, nymphs represented 91.7%, eggs 4.3%, and adults 4.0%. The lowest abundance was reported in January and could be interpreted as an inhibition of development caused by elevated temperatures. Something similar occurred in June (winter), when the lowest environmental temperatures were recorded, producing the greatest mortality of small nymphs, resulting in the presence of few or no specimens. The fluctuations in the density of this species can be attributed to bioclimatic factors and the availability of blood meals sources.

Palabras clave : Triatoma sordida; Butia yatay; population studies; seasonality; Corrientes; Argentina.