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Why ignoring your Darwinian fitness may be adaptive: Evolutionary dynamics of movement strategies in the presence of realistic constraints

Theodore Galanthay

Applied Mathematics,Ìý

Date and time:Ìý

Thursday, March 3, 2011 - 4:30pm

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In most theoretical habitat selection models, modelers assume that organisms tend to move to maximize their fitness.Ìý However, it remains unclear, especially in the presence of realistic constraints such as costs of movement and errors in habitat assessment, which general movement mechanisms might actually result in higher fitness and thus be termed adaptive.Ìý We study a single-species two-patch habitat selection model (of two coupled ordinary differential equations) and compute, analytically, optimal movement strategies that use both fitness-based and habitat-based information. We apply the tools of adaptive dynamics to show numerically that these strategies are evolutionarily and convergence stable.Ìý Strategies that incorporate information on fitness and habitat differences can be adaptive, whereas strategies based solely on information about fitness cannot.Ìý We show further that in the presence of realistic constraints, natural selection is predicted to favor those movement strategies that ignore information about fitness and use only habitat-based information.ÌýÌý In sum, to maximize its fitness, an organism should, in some cases, ignore information about fitness in favor of acting upon more proximate habitat cues.