Turbulent landscapes of pheromones during olfactory searches


May 3, 2016 - 12:00pm
Northwest 243
About the Speaker
Massimo Vergassola (UCSD)

The olfactory system of male moths is exquisitely sensitive to pheromones emitted by females and transported in the environment by atmospheric turbulence. Moths respond to minute amounts of pheromones and their behavior is sensitive to the fine-scale structure of turbulent plumes where pheromone concentration is detectible. The resulting signal of pheromone detections is qualitatively known to be intermittent and sporadic, yet quantitative characterization of its statistical properties is lacking. Such information would be particularly relevant for the design of olfactory stimulators, reproducing physiological signals in well-controlled laboratory conditions. I shall discuss a Lagrangian approach to the transport of pheromones by turbulent flows. Predictions for the statistics of odor detection during olfactory searches will be presented. The theory yields explicit probability distributions for the intensity and the duration of pheromone detections, as well as their spacing in time. Predictions are tested by using numerical simulations, laboratory experiments and field data for the atmospheric surface layer. Consequences for the dynamics of olfactory searches will follow.