On The Adaptive Use Of Information In Habitat Selection
Theodore Galanthay
Applied Mathematics, University of Colorado Boulder
Date and time:
Tuesday, June 18, 2013 - 3:00pm
Abstract:
Integrating evolution and ecology into mathematical models allows one to study the role of natural selection in ecological interactions. The dynamics of this process can be complicated since, at suitable spatial scales, landscapes are not homogeneous, and species interact across spatially variable environments. Thus, as a preliminary step to understanding how evolution shapes species-species interactions across space, we need to know what cues organisms actually use to guide movement.
We begin our inquiry by introducing a general model of single-species habitat selection that includes two sources of information, information on fitness and information on resources. In searching for evolutionarily stable strategies of information use, we discover that organisms constrained by perceptual limits may use an arbitrary combination of these two sources of information, but when realistic evolutionary costs are added, the strategy that maximizes fitness is the one that completely ignores information on fitness.
We analyze the model, which is an extension of previous two-patch models with population dynamics, and give sufficient conditions for the existence of an asymptotically stable equilibrium. We prove the global evolutionary stability and convergence stability of several of the information-use strategies, and we show that the addition of costs causes the equilibrium distribution to deviate from an ideal free (or, “equal fitness across patches”) distribution.
Finally, we explore how the evolution of random dispersal of prey, when population dynamics without movement are chaotic, changes with the introduction of a predator. We find that the predator can promote or prevent coexistence of two prey types with different dispersal rates. The outcome depends on the predator mortality rate which has a strong effect on the overall population dynamics of the system.