The evolution of food-web diversity based on body size and niche traits
Brännström et al. have developed an evolutionary food web model based on body size of individual species as the evolving trait. However, although this model is capable of producing food webs with three to four trophic levels, there is a certain regularity in the resulting food webs with, typically, equal spacing in body size on a logarithmic scale. During the summer program we would concentrate on extending this evolutionary food web model so that two ecologically different species with approximately the same body size can coexist. The approach would be to add an abstract “niche trait” representing the ecological niche that a species occupies. The ability of a predator to forage on a prey would then be determined by both relative difference in body size and the distance between the individuals in niche space. The evolutionary process will be analyzed following the small mutational steps and using a second degree approximation of the fitness landscape around the resident trait value. To track the evolution of the traits, we would adopt the canonical equation of adaptive dynamics. Along with the analytical techniques, we would employ suitable numerical simulations using software such as MATLAB.