FIGURE 1. Boxplot of time (h) of exposure of Bt and non-Bt cotton plants to different densities of A. gossypii emitting potentials of variation (VPs) (mV). Bt and non-Bt cotton plants were infested at densities of 30 and 60 aphids/plant (Bt.30, Bt.60, NBt.30 and NBt.60) and in the absence of aphids (Bt. Control and NBt. Control).