Odor tracking in marine organisms: the role of temporal and spatial intermittency of the odor signal
Odor tracking in marine organisms: the role of temporal and spatial intermittency of the odor signal
Abstract:
Animals use chemical cues to find food, mates, and avoid predators. In both terrestrial and aquatic environments, the instantaneous temporal and spatial distribution of odors is complex and plumes are often composed of intermittent filaments of chemicals at high concentrations that are adjacent to fluid with little or no odor. Navigation in chemical plumes has typically been considered as a spatial information problem where individuals track towards higher concentration. However, within turbulent plumes, concentration information alone is too variable to explain the search speed and accuracy of many animals. Sensory signals, including chemosensory signals, are generally assumed to be encoded by canonical, tonically active receptor neurons that respond to odor concentration. Recently, studies have demonstrated that a significant portion of primary olfactory receptor neurons (ORNs) in some animals are intrinsically rhythmically active or ‘bursting’. Laboratory and computational models show that these bursting olfactory receptor neurons (bORNS) can provide a mechanism for animals to sample and interpret the intermittency (i.e., on/off signal) of an odor environment. To test how organisms can utilize intermittency in search, we developed a computational fluid dynamics simulation of a turbulent odor plume as well as a plume within a large-scale laboratory water flume. We utilized the spiny lobster, Panulirus argus, as our model species. Our results show that utilizing the intermittency in the odor signal, in combination with concentration, greatly increases the efficiency of search and success in finding the source.