Evol Ecol Res 3: 829-844 (2001)     Full PDF if your library subscribes.

Resolution of evolutionary conflicts: costly behaviours enforce the evolution of cost-free competition

Roger Härdling,1* Henrik G. Smith,2 Veijo Jormalainen3 and Juha Tuomi4

1Division of Environmental and Evolutionary Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK, 2Department of Animal Ecology, Ecology Building, University of Lund, S-223 62 Lund, Sweden, 3Section of Ecology, Department of Biology, University of Turku, FIN-20014 Turku, Finland and 4Department of Biology, University of Oulu, Linnanmaa, FIN-90570 Oulu, Finland

Author to whom all correspondence should be addressed.
e-mail: rfh1n@udcf.gla.ac.uk


A resolution model for evolutionary conflicts of interest is proposed. We assume that two conflicting parties originally have different evolutionarily stable strategies (ESS) with respect to a continuous variable, but that only one value of the variable is simultaneously possible. Individuals from the two parties meet in antagonistic encounters. The side that invests more in the antagonistic behaviours mediating the conflict is able to adjust the variable in its preferred direction. It is shown that the extent of the conflict – that is, the difference between the ESS values of the parties – decreases with increases in investment to antagonistic behaviours. The precondition for this is that the total conflict cost increases with the intensity and frequency of the antagonistic encounters, and that these factors in turn are related to how much the variable is adjusted. The conflict costs then result in a change of ESS level that forces the stronger party to alter its preferred level of the conflict variable. Behaviours that give control in the conflict escalate in an ‘arms race’, which eventually leads to a compromise solution with one ESS shared by the parties and with a small or no realized cost of conflict behaviour. This result contrasts with the traditional view of evolutionary conflicts, that expressed costs of antagonistic behaviours are necessary for evolutionarily stable resolutions. The model is applied to sexual conflicts, where a stable resolution may result in which apparent conflict behaviours are suppressed, although both parties are ready to engage in costly conflicts. In an explicit model of the compromise resolution of a parent–offspring conflict over parental investment, we demonstrate that the conflict may be resolved so that offspring do not beg. At the solution, parents provide an amount of care intermediate between the original ESS level of the parents and offspring, and the new parental and offspring ESS levels are identical.

Keywords: conflict behaviour, evolutionary conflict, parent–offspring conflict, resolution compromise, sexual conflict.

IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.


        © 2001 Roger Härdling. 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.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.