Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.
1 Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
2 Evolution and Behaviour Research Group, School of Biology and Psychology, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
3 Department of Biology and Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON K1N 6N5, Canada
Abstract
Why should a microbe manufacture extracellular enzymes if its competitors can free-ride on these enzymes? Similarly, why should an animal place seeds into storage when others can exploit this stored resource? A solution to this general class of problems becomes apparent if one assumes that investors directly benefit from a proportion of the investments they make. Thus, when individuals benefit from a proportion p of their investments, but share the rest with other individuals in the system, then an evolutionarily stable level of investment can evolve which is higher the higher the value of p. These evolutionarily stable investment points mark the junction at which several classical games meet, so that changes in investment can move interactions from one game type to another. Non-zero optimal levels of investment also arise under conditions when investments are only shared locally, and even when producers lose more product to competitors than they save for themselves. Overall, this "personal gain" approach offers a simple yet robust explanation for why individuals engage in activities which may concomitantly benefit others.