[Antennal phenotype variation in sylvatic, peridomestic and domestic populations of Triatoma dimidiata (Hemiptera: Reduviidae) from Santander, Colombia]

Abstract

Introduction: Triatoma dimidiata is one of the widely distributed triatomines in Colombia. The phenotype of the antenna is a characteristic of populations that can differ among habitats and can give information concerning its biology and behavior. This information in turn can be used in the development of new methodological proposals for its control.

Objective: The behavior of populations of Triatoma dimidiate was studied in several different habitats, using the antennal phenotype.

Materials and methods: A mechanoreceptor and three chemoreceptors were compared in the antennae of 60 Triatoma dimidiata adults from several defined habitats in Santander, using unvariate and multivariate analyses.

Results: The multivariate analysis differentiated the female populations significantly. These differences were associated with variations in the number of thick-walled trichoids and with the numerical increase of the thin walled trichoids in habitats close to human housing. The males, with a larger number of sensilla and thin walled trichoids, were not differentiated significantly, although, similar tendencies were observed. Sexual dimorphism was clear in these characters in the total population, but less pronounced in the domestic populations.

Conclusions: The antennal sensilla patterns were useful in the intraspecific differentiation of Triatoma dimidiata in different habitats. The differences in the female population shed light on new sensorial arrangements for the exploration of the habitat, in contrast with the male populations that, because of their great capacity for dispersion, were not differentiated in the distinct habitats. The differences in sensilla patterns between females from urban areas and those from rural surroundings may be a simple and efficient marker of the origin of individual Triatominae attempting to colonize new habitats.