title: Stochastic optimal foraging: tuning intensive and extensive dynamics in random searches.
abstract: Recent theoretical developments had laid down the proper mathematical means to understand how the structural complexity of search patterns may improve foraging efficiency. Under information-deprived scenarios and specific landscape configurations, Lévy walks and flights are known to lead to high search efficiencies. Based on a one-dimensional comparative analysis we show a mechanism by which, at random, a searcher can optimize the encounter with close and distant targets. The mechanism consists of combining an optimal diffusivity (optimally enhanced diffusion) with a minimal diffusion constant. In such a way the search dynamics adequately balances the tension between finding close and distant targets, while, at the same time, shifts the optimal balance towards relatively larger close-to-distant target encounter ratios. We find that introducing a multiscale set of reorientations ensures both a thorough local space exploration without oversampling and a fast spreading dynamics at the large scale. Lévy reorientation patterns account for these properties but other reorientation strategies providing similar statistical signatures can mimic or achieve comparable efficiencies. Hence, the present work unveils general mechanisms underlying efficient random search, beyond the Lévy model. Our results suggest that animals could tune key statistical movement properties (e.g. enhanced diffusivity, minimal diffusion constant) to cope with the very general problem of balancing out intensive and extensive random searching. We believe that theoretical developments to mechanistically understand stochastic search strategies, such as the one here proposed, are crucial to develop an empirically verifiable and comprehensive animal foraging theory.
authors.affiliation: ICREA Movement Ecology Laboratory, CEAB-CSIC, Blanes, Spain; CREAF, Cerdanyola del Vallès, Barcelona, Spain.
authors.forename: Frederic
authors.initials: F
authors.lastname: Bartumeus
authors.affiliation: Laboratório de Física Teórica e Computacional, Departamento de Física, Universidade Federal de Pernambuco, Recife-PE, Brazil.
authors.forename: Ernesto P
authors.initials: EP
authors.lastname: Raposo
authors.affiliation: Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, Natal-RN, Brazil.
authors.forename: Gandhimohan M
authors.initials: GM
authors.lastname: Viswanathan
authors.affiliation: Departamento de Física, Universidade Federal do Paraná, Curitiba-PR, Brazil.
authors.forename: Marcos G E
authors.initials: MG
authors.lastname: da Luz
mesh_terms: D000818:Animals; D004058:Diffusion; D017753:Ecosystem; D005247:Feeding Behavior / Q000502:physiology*; D008954:Models, Biological; D011336:Probability; D013269:Stochastic Processes