title: Experimental evidence for inherent Lévy search behaviour in foraging animals.
abstract: Recently, Lévy walks have been put forward as a new paradigm for animal search and many cases have been made for its presence in nature. However, it remains debated whether Lévy walks are an inherent behavioural strategy or emerge from the animal reacting to its habitat. Here, we demonstrate signatures of Lévy behaviour in the search movement of mud snails (Hydrobia ulvae) based on a novel, direct assessment of movement properties in an experimental set-up using different food distributions. Our experimental data uncovered clusters of small movement steps alternating with long moves independent of food encounter and landscape complexity. Moreover, size distributions of these clusters followed truncated power laws. These two findings are characteristic signatures of mechanisms underlying inherent Lévy-like movement. Thus, our study provides clear experimental evidence that such multi-scale movement is an inherent behaviour rather than resulting from the animal interacting with its environment.
authors.affiliation: Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands Project Group Movement Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany Department of Biology, University of Konstanz, Konstanz, Germany akoelzsch@orn.mpg.de.
authors.forename: Andrea
authors.initials: A
authors.lastname: Kölzsch
authors.affiliation: Department of Spatial Ecology, Royal Netherlands Institute for Sea Research (NIOZ), Yerseke, The Netherlands Community and Conservation Ecology, Centre for Ecological and Evolutionary Studies, University of Groningen, Groningen, The Netherlands Terrestrial Ecology Unit, Ghent University, Ghent, Belgium.
authors.forename: Adriana
authors.initials: A
authors.lastname: Alzate
authors.affiliation: ICREA-Movement Ecology Laboratory, Centre for Advanced Studies of Blanes (CEAB-CSIC), Blanes, Spain CREAF, Barcelona, Spain.
authors.forename: Frederic
authors.initials: F
authors.lastname: Bartumeus
authors.affiliation: Department of Spatial Ecology, Royal Netherlands Institute for Sea Research (NIOZ), Yerseke, The Netherlands Institute of Environmental Biology, Utrecht University, Utrecht, The Netherlands.
authors.forename: Monique
authors.initials: M
authors.lastname: de Jager
authors.affiliation: Department of Spatial Ecology, Royal Netherlands Institute for Sea Research (NIOZ), Yerseke, The Netherlands HAS Hogeschool, University of Applied Sciences, 's Hertogenbosch, The Netherlands.
authors.forename: Ellen J
authors.initials: EJ
authors.lastname: Weerman
authors.affiliation: Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands Project Group Movement Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands Alterra and Forest and Nature Conservation Policy Group, Wageningen University and Research Centre, Wageningen, The Netherlands.
authors.forename: Geerten M
authors.initials: GM
authors.lastname: Hengeveld
authors.affiliation: Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands Project Group Movement Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands Behavioural Ecology Group, Animal Sciences Department, Wageningen University, Wageningen, The Netherlands.
authors.forename: Marc
authors.initials: M
authors.lastname: Naguib
authors.affiliation: Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands Project Group Movement Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.
authors.forename: Bart A
authors.initials: BA
authors.lastname: Nolet
authors.affiliation: Project Group Movement Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands Department of Spatial Ecology, Royal Netherlands Institute for Sea Research (NIOZ), Yerseke, The Netherlands.
authors.forename: Johan
authors.initials: J
authors.lastname: van de Koppel
mesh_terms: D000818:Animals; D017753:Ecosystem; D005247:Feeding Behavior; D015233:Models, Statistical; D009068:Movement; D012908:Snails / Q000502:physiology*
keywords: Hydrobia ulvae; Lévy walk; area-restricted search cluster; composite Brownian motion; landscape heterogeneity; multi-scale search behaviour