En el marco del Programa Nacional de Chagas y con los objetivos de comparar poblaciones de Triatoma infestans de origen geográfico diferente y determinar variaciones morfométricas de machos y hembras, se estudiaron poblaciones de vectores de 4 departamentos endémicos para la enfermedad de Chagas. Se midieron caracteres morfométricos, 7 de la cabeza y 4 de cada ala, de 150 ejemplares. El análisis uni y multivariado se utilizó para evaluar las variables de tamaño y conformación, quedando confirmado en este trabajo el dimorfismo sexual de los triatominos. En el análisis univariado no paramétrico, se observaron diferencias significativas en el tamaño y conformación de los ojos (P<0,05) así como en el largo total de la cabeza (P<0,01). En el análisis de componentes principales no se observaron diferencias importantes. Sin embargo, en el análisis discriminante las poblaciones de la Región Occidental (Boquerón y Pte Hayes) mostraron una tendencia conformar un solo grupo mientras que las de la Región Oriental (Paraguarí y Cordillera) tendían a ser diferentes de aquellas y entre sí (P<0,0001). Estos resultados apoyan la hipótesis de que las diferencias entre las poblaciones se pueden atribuir a factores ambientales. La evaluación de la forma o la persistencia de estas diferencias en generaciones sucesivas mantenidas en laboratorio,
podrá corroborar la existencia o no de variaciones genéticas entre las poblaciones.
In order to compare Triatoma infestans populations from different geographical origin and to study morphometric variations of male and female triatomines, populations from 4 departments endemic for Chagas disease were studies within the National Program of Chagas Control. Morphometric characters, 7 in the head and 4 in each wing, of 150 specimens were measured. T test was used to measure the differences bettween means and the uni and multi-variate analysis were used to evaluate size and conformations variables. The sexual dimorphism in size, with females being significantly bigger than males, is a general rule for triatomines which was confirmed by this study. Metric differences were also found, when comparing male (P<0.01) and female (P<0.05) insects from Easterm and Western regions, being smaller those from the former region. In the uni-variate non-parametric analysis, significant differences were observed in eye conformation and size (P<0.05) as well as in total length and head conformation(P<0.01). In specimens from the Departament of Paraguari, both variables were smaller. In the analysis of the main components, no significant differences were observed. However, in the discriminating analysis the populations of the Western region (Boqueron and Presidente Hayes) showed a trend of conforming only one group while the
populations of the Eastern region (Paraguari and Cordillera) tended to be different from the former and between them (P<0.0001). These results support the hypothesis stating that differences between populations could be attributed to environmental factors. The evaluation of the shape or the persistence of these differences in successive generations maintained in laboratory could corroborate the existence of genetic variations between
populations.
