The Tobacco Hornworm Moth, Manduca sexta

We study how the male tobacco hornworm moth Manduca sexta tracks female pheromone to its source by flying upwind in our laboratory wind tunnel. The interaction of the patchy odor distribution with moths' sensors and their movements results in them generating a side-to-side zigzagging pattern as they fly upwind. We have manipulated the size and shape of the source to study how the moths alter their behavior when the source width increases vertically or horizontally. We found that the moths' tracks get wider in wider plumes, but not taller in taller plumes.

We have also altered their visual horizon to study how this affects their tracking behavior. Surprisingly, we found that altering their visual pattern height does not significantly affect the structure of their tracking behavior in a pheromone plume.

Since a moth's antennae are multifunctional sensors, detecting both the odor and the wind speed during flight, we have begun to look at their antennal behavior as well. This work was done in collaboration with Drs. Sanjay Sane and Tom Daniel at the University of Washington.

We have recently begun to examine how the moth controls its flight by using high speed video to slow down the flight behavior for a finer scale analysis. We have also looked at Cercropia, a larger species of moth for comparison.