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Mutualism Among Free-living Species

  1. WS Armbruster1,
  2. G Rosenqvist2

Published Online: 15 DEC 2011

DOI: 10.1002/9780470015902.a0003287.pub2



How to Cite

Armbruster, W. and Rosenqvist, G. 2011. Mutualism Among Free-living Species. eLS. .

Author Information

  1. 1

    University of Portsmouth, Portsmouth, UK

  2. 2

    Norwegian University of Science and Technology, Trondheim, Norway

Publication History

  1. Published Online: 15 DEC 2011


Mutualisms are interspecific interactions resulting in benefits to both participants. In symbiotic mutualisms, the species live together for most of their lives. In nonsymbiotic mutualisms, members of the interacting species live apart most of the time and interact intermittently. Common mutualisms among free-living species include various plant–animal mutualisms, such as pollination and seed dispersal, and a number of animal–animal mutualisms such as cleaning and parasite-removal services (e.g. oxpeckers and cleaning wrasses). The evolutionary stability of these mutualisms is a topic of current research interest, in which mutualism may easily slip into unbalanced relationships wherein one partner exploits the other.

Key Concepts:

  • Mutualisms among free-living species are ecologically important, providing critical services for the maintenance of populations and functioning of ecosystems.

  • Mutualisms among free-living species may be evolutionarily more labile than symbiotic mutualisms, in which the former may more commonly ‘degenerate’ into exploitative relationships.

  • A key factor in the ecology and evolution of mutualisms among free-living species is signalling between spatially distant organisms, usually with behaviour, volatile chemicals and/or colour. The degree of honesty (or dishonesty) of such signalling is another topic of current research interest.


  • ecology;
  • evolution;
  • mutualism