LABORATORY COMPARISON OF FEEDING SUCCESS AMONG TRIATOMA-INFESTANS, T-GUASAYANA, AND T-SORDIDA (HEMIPTERA, REDUVIIDAE)

Success in obtaining a blood meal and rapid access to hiding places af ter feeding are the principal requirements triatomines have as they co lonize artificial ecotopes. Feeding success and postfeeding location o f 3rd and 5th instars of Triatoma sordida (Stal), of T. guasayana Wygo dzinsky & Abalos, and T. infestans (Klug) were studied in an experimen tal box in which triatomines and a chicken were left to interact overn ight. The bird was enclosed in a glass cube, slightly raised to allow triatomines to get in and out, turning the space outside into an exten sive refuge area. Four bunches of dry corn husks and a wooden panel we re also offered as shelters. Tile number of live and dead insects and their locations at the end of the experiment were recorded. Predation- as the percentage of missing insects-and success-as the percentage of insects alive and fed-were calculated. Interactions with the host were different among species and sometimes also between individuals of dif ferent life stages of the same species. Predation was always >20%. T. sordida was the best exploiter of the blood source, because 3rd instar s were more successful and 5th instars were as successful as the corre sponding T. infestans stages. Performance of T. guasayana was equivoca l because survival and feeding success were different for both instars . T. infestans showed a pronounced tendency to climb, and 3rd instars of T. guasayana were equally distributed in the upper half of the box and in tile corn husks, whereas the majority of T. sordida and 5th ins tars of T. guasayana sheltered in the husks.