Fig. 3. Orientation of the walking track as P. americana males left the release point to track a pheromone plume in zero wind after being pre-exposed to (A) wind + pheromone, (B) no wind + no pheromone, (C) wind only and (D) continuous wind and pheromone from the Series 2 experiments. Controls tracked plumes while being exposed to wind and pheromone continuously (D). On these circular plots due upwind=0° and downwind=180°. , angle of mean leaving direction; r, length of mean vector. r is distributed between 0 and 1, with 0 indicating no movement in the mean direction, and 1 indicating all movements were in the mean direction.