Behavioral response of fifth instar nymphs of Triatoma infestans (Hemiptera: Reduviidae) to pyrethroids

The hyperactivity (an increase in locomotor activity) and repellency produced by eight pyrethroids, applied as films on filter paper, were evaluated on fifth instar nymphs of Triatoma infestans (Hemiptera: Reduviidae) using a video tracking technique. All the pyrethroids studied produced hyperactivity. As a trend, hyperactivity produced by cyanopyrethroids was higher than that produced by non-cyanopyrethroids. Hyperactivity was not observed when nymphs were pretreated with the sulphydryl reagent N-ethylmaleimide before exposure to the pyrethroids. The eight pyrethroids failed to produce repellency. No repellency was also observed for the flowable formulation of deltamethrin at the concentration recommended for T. infestans control.