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

The hyperactivity (an increase in locomotor activity) and repellency produc ed by eight pyrethroids, applied as films on filter paper, were evaluated o n fifth instar nymphs of Triatoma infestans (Hemiptera: Reduviidae) using a video tracking technique. All the pyrethroids studied produced hyperactivi ty. 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 repell ency. No repellency was also observed for the flowable formulation of delta methrin at the concentration recommended for T. infestans control. (C) 2001 Elsevier Science B.V. All rights reserved.