Odor plume tracking behavior of walking and flying insects

Many animals locate food, mates, and territories by following plumes of attractive odors. There are clear differences in the structure of this plume tracking behavior depending on whether an animal is flying, swimming, walking, or crawling. These differences could arise from different control rules used by the central nervous system during these different modes of locomotion or one set of rules interacting with the different environments encountered by animals suspended in flow or moving across the ground. Flow speeds and turbulence that characterize the environments where walking and flying insects track plumes may alter the structure of odor plumes in an environment-specific way that results in the same control rules generating behaviors that appear quite different. We tested these ideas by challenging walking male cockroaches, Periplaneta americana, and flying male moths, Manduca sexta, to track plumes of their species’ sex-pheromones in low wind speeds characteristic of cockroach experimental environments, higher wind speeds characteristic of moth experimental environments, and conditions ranging from low to high turbulence. Introducing a turbulence-generating structure into the flow significantly improved the flying plume tracker’s ability to locate the odor source, and changed the structure of the behavior of both flying and walking plume trackers. Specifically, the walking and flying plume trackers located the odor source more often in experimental conditions characteristic of environments in which they live suggesting differing reliance on spatial and temporal measurements of the odor plume.

Methods
See the associated publication.