The Influence of PredatorPrey Population Dynamics on the Longterm Evolution of Food Web S.pdfVIP

The Influence of Predator-Prey Population Dynamics on the Long-term Evolution of Food Web Structure Barbara Drossel1,3, Paul G. Higgs2 and Alan J. McKane1 0 0 1Department of Theoretical Physics and the 2School of Biological Sciences, 0 2 University of Manchester, Manchester M13 9PL, UK b e 3School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, F 0 Tel Aviv University, Tel Aviv 69978, Israel 2 ] O A. Abstract n i l n [ We develop a set of equations to describe the population dynamics of many interacting species 1 in food webs. Predator-prey interactions are non-linear, and are based on ratio-dependent v 2 3 functional responses. The equations account for competition for resources between members 0 2 of the same species, and between members of different species. Predators divide their to- 0 0 0 tal hunting/foraging effort between the available prey species according to an evolutionarily / n i stable strategy (ESS). The ESS foraging behaviour does not correspond to the predictions l n : of optimal foraging theory. We use the population dynamics equations in simulations of the v i X Webworld model of evolving ecosystems. New species are added to an existing food web r a due to speciation events, whilst species become extinct due to coevolution and competition. We study the dynamics of species-diversity in Webworld on a macro-evolutionary timescale. Coevolutionary interactions are strong enough to cause continuous overturn of species, in contrast to our previous Webworld simulations with simpler population dynamics. Although there are significant fluctuations in species diversity because