AMMONIA AND COLORS AS ATTRACTANTS TO Rhodnius prolixus (HEMIPTERA: REDUVIIDAE, TRIATOMINAE).

Triatomines (Hemiptera, Triatominae) are the vector insects of the protozoan parasite Trypanosoma cruzi, the etiological agent of Chagas disease. In this study, we evaluate these insects' preferences for a number of colored light emitting diodes (LEDs) under laboratory conditions. Then, we combine some of these colored lights with ammonia in order to evaluate the effect that such bimodal stimulation could have on Rhodnius prolixus, historically recognized as the main vector of T. cruzi in Venezuela. A Y-tube dual choice photo-olfactometer was used to carry out behavioral experiments on fifth-instar triatomine nymphs. At the ends of the Y-tube bifurcation monochromatic lights, produced by LEDs, and ammonia were offered. Our results show that blue light attracted R. prolixus (P < 0.01) and that other colors (ultraviolet, green, yellow, red and white) did not lead to positive phototaxis. Ammonia combined with white or blue light, attracted these triatomine insects (P < 0.05). In fact, stimulation with ammonia plus white light resulted in higher attraction than the smell by itself, giving evidence of additive or synergistic effect. In light of our findings, future challenges include understanding, on an ecological level, of the 'adaptive' (sensu lato) values of this behavior. Our results confirm the potential of ammonia and blue LEDs used in insecttraps. [ABSTRACT FROM AUTHOR]