Meeting Abstract
24.4 Jan. 5 Three-Dimensional Concentration Measurements Around Actively Tracking Blue Crabs JACKSON, Jennifer L*; DICKMAN, Brian D; WEISSBURG, Marc J; WEBSTER, Donald R; Georgia Institute of Technology; Georgia Institute of Technology; Georgia Institute of Technology; Georgia Institute of Technology jennifer.jackson@gatech.edu
The fluctuating properties of odor signals in turbulent boundary layer flows are used by large marine invertebrate predators (e.g., blue crabs) to navigate towards, and locate, food and mates. A firm understanding of mechanisms underlying navigation in fluid borne plumes has been limited due to our inability to precisely define the relationship between stimulus patterns and behavioral output. To link these two phenomena, we have developed an integrated measurement system to simultaneously quantify the instantaneous odor concentration surrounding a freely tracking blue crab (Callinectes sapidus) using three-dimensional laser-induced fluorescence (3DLIF). C. sapidus receives chemical stimulus at several locations, including the antennules and the distal tips of the legs. Due to this spatial arrangement of chemosensors, 3D measurements of the concentration field are required to link behavior to plume structure. The concentration field is measured via 3DLIF by compiling horizontal laser scans separated by a small vertical distance and walking kinematics of tracking crabs were simultaneously recorded. During trials, crabs began their search 150 cm downstream of a source and were reversibly �blindfolded� to prevent aversive reactions to the intense laser light. The concentration field data around a tracking animal is used to determine how hypothesized navigational cues, such as concentration bursts at the antennules and spatial asymmetry in concentration at the distributed chemosensory organs on the legs, results in particular decisions during navigation. In addition, we can examine the roles of stimulation history and comparison between information across various vertical regions as navigational cues.
