• Pheromone;
  • plume;
  • puff trajectory;
  • pheromone dispersion;
  • anemotaxis;
  • threshold;
  • Lymantria dispar;
  • gypsy moth

ABSTRACT. Pheromone released from a point source beneath a forest canopy usually follows a non-linear trajectory as demonstrated by the paths of small, neutrally-buoyant, helium-filled balloons or puffs of smoke. Mark-recapture experiments show that few male gypsy moths (Lymantria dispar L.) follow a pheromone plume over distances greater than 80 m even though they can easily detect pheromone at that distance as indicated by wingfanning assay. The directional consistency of successive puffs of pheromone appears more important than the linearity of their trajectories in enabling males to locate a pheromone source.