Adaptive Control of Odor-Guided Locomotion: Behavioral Flexibility as an Antidote to Environmental Unpredictability1

Abstract

Many animals find distant unseen resources by guiding their locomotion through fluid media, using olfactory information acquired from plumes of odorant molecules issuing from the resource of interest. This behavior occurs in birds and fish, but much of our knowledge of it derives from flying insects, especially moths. It is a highly integrative behavior, requiring not only the integration of olfactory information with a behavioral strategy to maintain contact with the odor plume, but also an ability to detect the direction of fluid flow that is carrying the odor cue. The temporal-spatial structure of the odor plume is determined by the fluid dynamics of the environment, and it profoundly affects the behavior. Thus, the success of animals (or artificial agents) is determined by an interaction between sensory input and internally generated behaviors. We have implemented behavioral-level simulations of odor-modulated moth flight to understand how the properties of the odor stimulus and the behavioral system interact to result in successful source location. Even simple reflexive models can track predictable, laminar-flow plumes, but only models with internally generated behaviors can track unpredictable, turbulent plumes. The "best" behavioral strategy depends on both the structure of the odor stimulus and an agent's performance limits.