Covering Ground: Movement Patterns and Random Walk Behavior in Aquilonastra anomala Sea Stars.

Journal Article (Journal Article)

The paths animals take while moving through their environments affect their likelihood of encountering food and other resources; thus, models of foraging behavior abound. To collect movement data appropriate for comparison with these models, we used time-lapse photography to track movements of a small, hardy, and easy-to-obtain organism, Aquilonastra anomala sea stars. We recorded the sea stars in a tank over many hours, with and without a food cue. With food present, they covered less distance, as predicted by theory; this strategy would allow them to remain near food. We then compared the paths of the sea stars to three common models of animal movement: Brownian motion, Lévy walks, and correlated random walks; we found that the sea stars' movements most closely resembled a correlated random walk. Additionally, we compared the search performance of models of Brownian motion, a Lévy walk, and a correlated random walk to that of a model based on the sea stars' movements. We found that the behavior of the modeled sea star walk was similar to that of the modeled correlated random walk and the Brownian motion model, but that the sea star walk was slightly more likely than the other walks to find targets at intermediate distances. While organisms are unlikely to follow an idealized random walk in all details, our data suggest that comparing the effectiveness of an organism's paths to those from theory can give insight into the organism's actual movement strategy. Finally, automated optical tracking of invertebrates proved feasible, and A. anomala was revealed to be a tractable, 2D-movement study system.

Full Text

Duke Authors

Cited Authors

  • Lohmann, AC; Evangelista, D; Waldrop, LD; Mah, CL; Hedrick, TL

Published Date

  • October 2016

Published In

Volume / Issue

  • 231 / 2

Start / End Page

  • 130 - 141

PubMed ID

  • 27820905

Electronic International Standard Serial Number (EISSN)

  • 1939-8697

International Standard Serial Number (ISSN)

  • 0006-3185

Digital Object Identifier (DOI)

  • 10.1086/690093

Language

  • eng