Evolutionary Ecology

, Volume 7, Issue 2, pp 175–198

Polymorphism in heterogeneous environments, evolution of habitat selection and sympatric speciation: Soft and hard selection models

  • T. de Meeûs
  • Y. Michalakis
  • F. Renaud
  • I. Olivieri
Article

DOI: 10.1007/BF01239387

Cite this article as:
de Meeûs, T., Michalakis, Y., Renaud, F. et al. Evol Ecol (1993) 7: 175. doi:10.1007/BF01239387

Summary

The adaptation to a variable environment has been studied within soft and hard selection frameworks. It is shown that an epistatically determined habitat preference, following a Markovian process, always leads to the maintenance of an adaptive polymorphism, in a soft selection context. Although local mating does not alter the conditions for polymorphism maintenance, it is shown that, in that case, habitat selection also leads to the evolution of isolated reproductive units within each available habitat. Habitat selection, however, cannot evolve in the total absence of adaptive polymorphism. This represents a theoretical problem for all models assuming habitat selection to be an initially fixed trait, and means that within a soft selection framework, all the available habitats will be exploited, even the less favourable ones.

On the other hand, polymorphism cannot be maintained when selection is hard, even when all individuals select their habitat. Here, the evolution of habitat selection does not need any prerequisite polymorphism, and always leads to the exploitation of only one habitat by the most specialized genotype. It appears then that hard selection can account for the existence of empty habitat and for an easier evolution of habitat specialization.

Keywords

polymorphism variable environments habitat selection speciation soft selection hard selection 

Copyright information

© Chapman & Hall 1993

Authors and Affiliations

  • T. de Meeûs
    • 1
  • Y. Michalakis
    • 1
  • F. Renaud
    • 1
  • I. Olivieri
    • 1
  1. 1.Laboratoire de Parasitologie Comparée, URA 698 CNRSUniversité Montpellier II (USTL)Montpellier Cedex 05France
  2. 2.Domaine de MelgueilStation INRA d'Amélioration des Plantes de MontpellierMauguioFrance