Print PageMost consumers, except extreme specialists, rely on several resources that may have different mobilities. Predators have preys whose dispersal abilities differ, plants rely on different nutrient whose diffusion rates may also differ. These dispersal differences have profound effects on the availability and reliability of resources, thereby affecting the long term probability of survival of the consumer.
Here, I consider an evolutionary model studying how specialization of a consumer on subsets of resources depends on the differences of mobility. The goal is to understand under what conditions these differences in mobility create disruptive selection, therefore the possibility of emergent diversity at the consumer level.
The issue is studied using a simple local model, in which differences of mobility affect the input/output balance of the resources sustaining the consumer species. Different scenarios are considered depending on the identity of the consumer (predator, plant), and of the resources (prey species, nutrient types, nutrient forms). The model is then put on a grid to study how such asymmetries create spatial heterogeneity in the resources distribution and the effects of such heterogeneity on the emergence of consumer diversity.
Results/Conclusions
Results of the local model suggest that disruptive selection is usually strong, except when mobilities of the resources are very contrasted. This qualitative result does not depend on the type of consumer and resources considered. This suggests that large asymmetries in resource dispersal may constrain the emergence and maintenance of diversity. Results of the spatial model are however more complex, as the spatial heterogeneity created in resource distribution depends on the type of ressource considered (nutrient vs prey), and components of its dynamics (recycling processes in the case of nutrient).
