Adaptive Lévy Walks and Area-restricted Search in Human Foraging

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Hills, T. ; Kalff, C. ; Wiener, J.M. (2013)
  • Publisher: Public Library of Science
  • Journal: PLoS ONE (vol: 8)
  • Related identifiers: doi: 10.1371/journal.pone.0060488, doi: 10.1371/journal.pone.0060488, pmc: PMC3618454
  • Subject: Social and Behavioral Sciences | Probability Theory | Research Article | Biology | BF | Mathematics | Veterinary Science | Animal Behavior | Behavioral Ecology | Mental Health | Medicine | Statistical Distributions | Agriculture | QA | Ecology | Evolutionary Biology | Psychology | Physics | Animal Management | Behavior | Zoology

A considerable amount of research has claimed that animals’ foraging behaviors display movement lengths with power-law\ud distributed tails, characteristic of Le\ud ́\ud vy flights and Le\ud ́\ud vy walks. Though these claims have recently come into question, the\ud proposal that many animals forage using Le\ud ́\ud vy processes nonetheless remains. A Le\ud ́\ud vy process does not consider when or\ud where resources are encountered, and samples movement lengths independently of past experience. However, Le\ud ́\ud vy\ud processes too have come into question based on the observation that in patchy resource environments resource-sensitive\ud foraging strategies, like area-restricted search, perform better than Le\ud ́\ud vy flights yet can still generate heavy-tailed\ud distributions of movement lengths. To investigate these questions further, we tracked humans as they searched for hidden\ud resources in an open-field virtual environment, with either patchy or dispersed resource distributions. Supporting previous\ud research, for both conditions logarithmic binning methods were consistent with Le\ud ́\ud vy flights and rank-frequency methods–\ud comparing alternative distributions using maximum likelihood methods–showed the strongest support for bounded\ud power-law distributions (truncated Le\ud ́\ud vy flights). However, goodness-of-fit tests found that even bounded power-law\ud distributions only accurately characterized movement behavior for 4 (out of 32) participants. Moreover, paths in the patchy\ud environment (but not the dispersed environment) showed a transition to intensive search following resource encounters,\ud characteristic of area-restricted search. Transferring paths between environments revealed that paths generated in the\ud patchy environment were adapted to that environment. Our results suggest that though power-law distributions do not\ud accurately reflect human search, Le\ud ́\ud vy processes may still describe movement in dispersed environments, but not in patchy\ud environments–where search was area-restricted. Furthermore, our results indicate that search strategies cannot be inferred\ud without knowing how organisms respond to resources–as both patched and dispersed conditions led to similar Le\ud ́\ud vy-like\ud movement distributions
  • References (37)
    37 references, page 1 of 4

    1. Ayala-Orozco BR, Cocho G, Larralde HN, Ramos-Ferna´ndez G, Mateos JL, et al. (2004) Le´vy walk patterns in the foraging movements of spider monkeys (Ateles geoffroyi). Behavioral Ecology and Sociobiology 55: 223-230.

    2. Brown C, Liebovitch L, Glendon R (2007) Le´vy flights in Dobe Ju/'hoansi foraging patterns. Human Ecology 35: 129-138.

    3. Reynolds A, Smith A, Reynolds D, Carreck NL, Osborn JL (2007) Honeybees perform optimal scale-free searching flights when attempting to locate a food source. Journal of Experimental Biology 210: 3763-3770.

    4. Reynolds A, Rhodes CJ (2009) The Le´vy flight paradigm: random search patterns and mechanisms. Ecology 90: 877-887.

    5. Viswanathan G, Afanasyev V, Buldyrev S, Murphy EJ, Prince PA, et al. (1996) Le´vy flight search patterns of wandering albatrosses. Nature 381: 413-415.

    6. Humphries NE, Queiroz N, Dyer JRM, Pade NG, Musyl MK, et al. (2010) Environmental context explains Le´vy and Brownian movement patterns of marine predators. Nature 465: 1066-1069.

    7. Edwards AM (2011) Overturning conclusions of Le´vy flight movement patterns by fishing boats and foraging animals. Ecology 92: 1247-1257.

    8. Applebaum D. (2004). Le´vy Processes and Stochastic Calculus. Cambridge: Cambridge University Press.

    9. Bell W (1990) Searching behavior patterns in insects. Annual Review of Entomology 35: 447-467.

    10. Hills T, Brockie PJ, Maricq AV (2004) Dopamine and glutamate control arearestricted search behavior in Caenorhabditis elegans. Journal of Neuroscience 24: 1217-1225.

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