Document Detail


Prey density, value, and spatial distribution affect the efficiency of area-concentrated search.
MedLine Citation:
PMID:  22995820     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Searching individuals need to take decisions on where and how long to search. When food is spatially aggregated, detection of a food item signals an probability for the presence of further prey items in its surrounding. Organisms can thus intensify search effort upon detecting a prey item, but after unsuccessfully searching for a while, return to the previous, extensive search, this strategy is known as 'area-concentrated-search' (ACS). Here we present results of simulations where individuals perform ACS employing a correlated random walk with variable directional persistence. Switching between intensive and extensive search (with respectively low and high directional persistence) is a function of searcher's internal state represented as 'satiety' level depending on preceding consumption of prey items. We explore the effect of this function's control parameters ('switching level' i.e. the satiety at which the switching occurs, and the switchover shape parameter) on searching efficiency in dependence of (1) prey items' spatial distribution ranging from randomly uniform to highly contagious, (2) the overall prey density, and (3) prey 'caloric' value. Our main conclusions: (1) the form of the adopted switchover exerts an effect on searching efficiency, and this effect is most pronounced in landscapes with highly aggregated resources. Except for the most homogeneous prey distributions, there was a clear optimum area within the movement parameter space, yielding highest efficiency. (2) The optimal switching level is larger in heterogeneous landscapes, but optimum switchover shape is little affected by any of the landscape attributes. In most landscapes, it is most profitable to switch gradually rather than abruptly. (3) The success and optimal switching level depend not only on the prey's spatial distribution but also on average prey density while the value of prey items has little effect on the optimal movement parameters.
Authors:
Kamil A Bartoń; Thomas Hovestadt
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-9-17
Journal Detail:
Title:  Journal of theoretical biology     Volume:  -     ISSN:  1095-8541     ISO Abbreviation:  J. Theor. Biol.     Publication Date:  2012 Sep 
Date Detail:
Created Date:  2012-9-21     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0376342     Medline TA:  J Theor Biol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2012 Elsevier Ltd. All rights reserved.
Affiliation:
Field Station, University of Würzburg, Glashüttenstrasse 5, Fabrikschleichach, D-96181 Rauhenebrach, Germany. Electronic address: kamil.barton@uni-wuerzburg.de.
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