Abstract
Crustaceans such as crabs, lobsters and crayfish use dispersing odorant molecules to determine the location of predators, prey, potential mates and habitat. Odorant molecules diffuse in turbulent flows and are sensed by the olfactory organs of these animals, often using a flicking motion of their antennules. These antennules contain both chemosensory and mechanosensory sensilla, which enable them to detect both flow and odorants during a flick. To determine how simultaneous flow and odorant sampling can aid in search behavior, a 3-dimensional numerical model for the near-bed flow environment was created. A stream of odorant concentration was released into the flow creating a turbulent plume, and both temporally and spatially fluctuating velocity and odorant concentration were quantified. The plume characteristics show close resemblance to experimental measurements within a large laboratory flume. Results show that mean odorant concentration and it's intermittency, computed as dc/dt, increase towards the plume source, but the temporal and spatial rate of this increase is slow and suggests that long measurement times would be necessary to be useful for chemosensory guidance. Odorant fluxes measured transverse to the mean flow direction, quantified as the product of the instantaneous fluctuation in concentration and velocity, v′c′, do show statistically distinct magnitude and directional information on either side of a plume centerline over integration times of <0.5 s. Aquatic animals typically have neural responses to odorant and velocity fields at rates between 50 and 500 ms, suggesting this simultaneous sampling of both flow and concentration in a turbulent plume can aid in source tracking on timescales relevant to aquatic animals.
Highlights
For the crayfish Orconectes virilis changes in the temporal pattern of odorant stimulation was found to drive changes in the temporal patterns of behavior while undergoing search [37]. It has been shown in blue crabs Callinectes sapidus that both rheotaxis and chemotaxis is necessary for successful orientation while tracking food odors [38]. These findings suggest that these organisms utilize both hydrodynamic and chemical stimuli to aid in search behavior, but what chemical and flow information these organisms use, and how it is integrated at the level of the antennule or brain remains poorly understood
Velocity vectors, computed from Particle Image Velocimetry (PIV) analysis, were superimposed over the planar laser-induced fluorescence system (PLIF) image to quantify simultaneous water velocities and odorant concentrations 1 m downstream from the source, along the plume centerline (Figure 4C)
This study shows that simultaneous sampling of both flow and odorant concentration can provide valuable cues for tracking of odorant plumes compared to sampling of odorants alone
Summary
Crustaceans such as crabs, lobsters and crayfish use chemo- and mechano-reception to track sources of odorant plumes to locate mates, food, and living habitat [1,2,3,4,5,6]. Odorants in the benthic flow are carried to the olfactory organs of the animal through turbulent water currents and diffuse toward the surface of the organs where chemoreceptors are located. These olfactory organs contain mechano-receptors that provide information about the turbulent flow, and together with odorant concentration help the animal locate the source of the chemical plume [7]. To understand the mechanism of chemical plume tracking in aquatic animals, we must understand the small scale diffusive flow of odorants near the olfactory organs of the animals, and the large scale turbulent nature of the chemical plume
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
