Natural ecotopes of Triatoma infestans dark morph and other sylvatic triatomines in the Bolivian Chaco

A survey of natural ecotopes of Triatoma infestans dark morph and other tri atomine sylvatic species was performed in an uninhabited area of the Bolivi an Chaco. Among the 321 triatomines collected by light trapping, only 4 T. infestans dark morph specimens were identified. Predominant flying species were T. guasayana and T. sordida group 2 (51.7% and 37.1% of capture, respe ctively). The same species prevailed in terrestrial and epiphytic bromeliad s where scarce T. infestans dark morph nymphal instars were also detected. In parrot nests T. delpontei prevailed broadly over other species (90.2% of the capture) and only 4 T. infestans dark morph adults were collected. In contrast, T. infestans dark morph was the predominant species captured in h ollow trees (46.0% of the total collected). The abundance of immature forms (88.2% of the collection) shows that hollow trees constitute a favourable ecotope for this species. Of the 421 trees investigated, 33.7% were positiv e for triatomines. T. infestans dark morph, found inside 15.0% of them, als o had higher apparent density than other species (average number Of T. infe stans in positive trees, 2.0 +/- 1.6 vs 1.3 +/- 0.6 for other species). Lig ht trapping seems to be an efficient method to sample the T. sordida-T. gua sayana complex in that it shows a similar distribution to that observed in natural ecotopes; however, this method is ineffective for the assessment of the local abundance of T. infestans dark morph.