The characteristics of species in an evolutionary food web model.

We explore the consequences of modifying the way in which species are defined in an evolutionary food web model. In the original version of the model, the species were defined in terms of a fixed number of features, chosen from a large number of possibilities. These features represented phenotypic and behavioural characteristics of the species. Speciation consisted in occasionally replacing one of the features by another. Here we modify this scheme by firstly allowing for a richer structure and secondly by testing whether we are able to eliminate the need for an explicit choice of features altogether. In the first case we allow for changing the number of features which define a species, as well as their nature, and find that in the resulting webs the higher trophic levels typically contain species with the greatest number of features. In the second case, by a simplification of the mechanisms for inter and intra-species competition, we construct a model without any explicit features and find that we are still able to grow model food webs. We assess the quality of the food webs produced and discuss the consequences of our findings for the future modelling of food webs.

[1]  Alan J. McKane,et al.  The robustness of the Webworld model to changes in its structure , 2008 .

[2]  Barbara Drossel,et al.  The impact of nonlinear functional responses on the long-term evolution of food web structure. , 2004, Journal of theoretical biology.

[3]  W. Godwin.  Article in Press , 2000 .

[4]  R. Solé,et al.  Mean-field stochastic theory for species-rich assembled communities. , 2000, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[5]  B. Drossel,et al.  Modelling Food Webs , 2002, nlin/0202034.

[6]  Christopher Quince,et al.  Topological structure and interaction strengths in model food webs , 2004, q-bio/0402014.

[7]  Katsuhiko Yoshida.  Dynamics of evolutionary patterns of clades in a food web system model , 2003, Ecological Research.

[8]  B. Drossel,et al.  The influence of predator--prey population dynamics on the long-term evolution of food web structure. , 2000, Journal of theoretical biology.

[9]  Caldarelli,et al.  Modelling Coevolution in Multispecies Communities. , 1998, Journal of theoretical biology.

[10]  K. Tokita,et al.  Emergence of a complex and stable network in a model ecosystem with extinction and mutation. , 2002, Theoretical population biology.

[11]  Barbara Drossel,et al.  Models of Food-Web Evolution , 2006 .

[12]  Katsuhiko Yoshida,et al.  Evolutionary dynamics of species diversity in an interaction web system , 2003 .

[13]  Neo D. Martinez,et al.  Network structure and biodiversity loss in food webs: robustness increases with connectance , 2002, Ecology Letters.

[14]  Michio Kondoh,et al.  Foraging Adaptation and the Relationship Between Food-Web Complexity and Stability , 2003, Science.

[15]  M. Pascual,et al.  Ecological networks : Linking structure to dynamics in food webs , 2006 .

[16]  B. Drossel,et al.  Modelling evolving food webs , 2005 .

[17]  M. Maron,et al.  An Ecological Approach to the Evolution of Organism Complexity , 2004 .

[18]  Alan J. McKane,et al.  Evolving complex food webs , 2004 .

[19]  C. Titus Brown,et al.  Evolutionary Learning in the 2D Artificial Life System "Avida" , 1994, adap-org/9405003.

[20]  E. Hill.  Journal of Theoretical Biology , 1961, Nature.

[21]  A G Rossberg,et al.  Some properties of the speciation model for food-web structure-mechanisms for degree distributions and intervality. , 2005, Journal of theoretical biology.

[22]  James Rosindell,et al.  Unified neutral theory of biodiversity and biogeography , 2010, Scholarpedia.

[23]  M. Lässig,et al.  Shape of ecological networks. , 2001, Physical review letters.