Apparency of pulsed and continuous pheromone to male gypsy moths.

Quiescent male gypsy moths (Lymantria dispar) exposed in a wind tunnel to either pulsed (0.5-, 2- or 5-sec on, followed by a two-fold time interval off) or continuous streams of synthetic pheromone responded similarly in the proportions and latencies of wing fanning. Similarly, upwind anemotactic flight tracks in pulsed (1-sec on and 1-sec off) and continuous plumes of pheromone were indistinguishable. These data suggest that in the gypsy moth (1) pulsed pheromone stimuli would not lower the threshold, despite the improvement in the signal-to-noise ratio; and (2) temporal modulation of the pheromone plume at 1-sec intervals does not alter the "preprogrammed" upwind flight pattern.