Evol Ecol Res 6: 125-145 (2004)     Full PDF if your library subscribes.

Implications of habitat choice for protected polymorphisms

Virginie Ravigné,1* Isabelle Olivieri1 and Ulf Dieckmann2

1Laboratoire Génétique et Environnement, Institut des Sciences de l’Évolution de Montpellier, cc065, Université Montpellier 2, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France and  2Adaptive Dynamics Network, International Institute for Applied Systems Analysis, Schlossplatz 1, A-2361 Laxenburg, Austria

Author to whom all correspondence should be addressed.
e-mail: ravigne@isem.univ-montp2.fr

ABSTRACT

In this paper, we re-examine how heterogeneous environments can enable protected polymorphisms. Building on the classical models by Levene and Dempster of dispersal and selection in two habitats, we systematically investigate how the maintenance of polymorphisms is affected by (1) local versus global density regulation and (2) constant versus variable output from habitats to the next generation. We show that, for populations capable of habitat choice, a third independent and fundamental class of models needs to be considered. It is characterized by local density regulation (like Levene’s model) and variable habitat output (like Dempster’s model). Our results indicate that the conditions determining whether a system allows for protected polymorphisms differ qualitatively in the presence and absence of matching habitat choice (which occurs when individuals prefer the habitat to which they are best adapted). Without such habitat choice, the salient distinction is not between local and global density regulation, but between constant and variable habitat output. With matching habitat choice this situation is reversed. Analysis of the third class of models introduced here suggests that the joint evolution of matching habitat choice and local-adaptation polymorphism is easier than was previously thought.

Keywords: Dempster, density regulation, hard selection, heterogeneous environments, Levene, local adaptation, soft selection, specialization, subdivided populations.

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        © 2004 Virginie Ravigné. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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