Study of flight patterns of insects using odor navigation in windy environment

Several mechanisms control male moth’s navigation towards a female releasing sex pheromone. Optomotor anemotaxis is a visual mechanism for the moth flight direction relative to the ground, mechanoreceptors are used for calculating its speed relative to the air current and chemoreceptors on the antennae for sampling the pheromone concentration in the air. All together result in a zigzagging flight pattern of the male moth that depends on the characteristics of its encounters with the pheromone plume. We investigate how turbulence manifests the male flight behavior in respect to the streamwise current that carries the pheromone, emphasizing a relationship between the flight speed and the turbulent plume properties. The interaction between the moth flight and the flow field characteristics are examined in a wind tunnel where moth trajectory is recorded. Particle image velocimetry (PIV) and scalar imaging technique are utilized for measuring velocities and scalar concentration distribution in the tunnel. The role of turbulence in the moth navigation is evaluated by correlating the moth trajectory path with the flow properties. We have found that the moth’s upwind motion is related to the streamwise variations of the pheromone concentration while the zigzagging  motion is correlated with the cross-stream turbulent flow fluctuations.