Policy and Complex Systems - Volume 2 Number 1 - Spring 2015
Predator – Prey Dynamics and the Red Queen Hypothesis : Putting Limits on the Evolutionary Arms Race
Ted Carmichael A , B & Mirsad Hadzikadic A
Computer simulations of complex food webs are an important tool for deepening our understanding of these systems . Yet most computer models assume , rather than generate , key system-level patterns , or use mathematical modeling approaches that make it difficult to account for non-linearities . In this article , we present a computer simulation model that addresses these concerns by using agent-based modeling techniques , so that system-level patterns emerge from the interactions of thousands of individual simulated agents . In previous work , this model replicated fundamental properties of an ecosystem . This work extends the model in the context of the Red Queen hypothesis . We find that improvements in the competitive landscape for a single predator agent do not generally confer a benefit on the species as a whole , and may even be detrimental . Additional experiments that explicitly account for energy requirements and allow individual evolution illustrate how natural means limit arms races . This model can serve as a platform for evaluating policy options for developing sustainable systems , both in terms of long-term and short-term desired outcomes .
Keywords : predator-prey , agent-based modeling , Red Queen hypothesis , evolutionary dynamics , population dynamics , complex adaptive systems .
I - Introduction
The literature on marine and
terrestrial ecosystems is extensive and diverse , encompassing both theoretical models and empirical surveys ( Christensen et al ., 2003 ; DeAngelis & Mooij , 2007 ; Frank , Petrie , Choi , & Leggett , 2003 ; Grimm , 1999 ). Some significant differences between model results and real-world surveys have persisted for years , and it has been difficult identifying fundamental principles relative to the many complicating factors within existent ecosystems . For example , in the early 1980s , Oksanen , Fretwell , Arruda , and Niemelä ( 1981 ) examined multiple trophic levels in a predator – prey system using mathematical models , in order to determine whether resources fundamentally control species population ( biomass )— as was the conventional wisdom at the time — or by predation .
More recently , researchers have begun to ask , not which process ( bottomup resources versus top-down predation ) controls population overall , but rather how these two forces interact under different spatial and temporal scenarios ( Reid , Battle , Batten , & Brander , 2000 ). Many scientists think that this new approach will help reveal how the combined effects of resourcemediated and predator-mediated forces influence the resilience of food webs ( Casini et al ., 2008 ). This suggestion leads naturally to the view that ecosystems can be productively
A
Department of Software and Information Systems , UNC Charlotte , Charlotte , NC 28223 , USA
B
TutorGen , Inc ., Fort Thomas , KY 41075 , USA 10.18278 / jpcs . 2.1.7
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