July 15, 2015

Will anyone bid more?

Johannes Reiter adds new model to evolutionary game theory • Shortage of resources contributes to speciation

Johannes Reiter and Krishnendu Chatterjee photo by Reiner Riedler © IST Austria
Johannes Reiter and Krishnendu Chatterjee. Reiner Riedler / IST Austria

The competition for resources among cells, individuals or species is a fundamental characteristic of evolution. In a paper appearing in the Proceedings of the Royal Society B on July 15, 2015, Johannes Reiter and co-authors from the Institute of Science and Technology (IST Austria) and Martin A. Nowak from Harvard University add a new model to the framework of evolutionary game theory.

So-called biological all-pay auctions have previously been used to model situations where multiple individuals compete for a single resource. In this kind of auction the cost of the individual corresponds to their bid irrespective of who wins the reward (for example the spent energy and the risk of injury in a fight for a territory). However, in many situations multiple resources with various values exist and single reward auctions are not applicable.

In their paper, Johannes Reiter and his colleagues generalize the existing model to include a competition for multiple rewards and study the evolution of strategies in this new model. The decreasingly ordered rewards are distributed according to the decreasingly ordered bids (strategies) of the participating individuals. The inferred evolutionary stable strategies for the multiple reward case are qualitatively very different from the single reward case. In a situation where only few individuals compete for few resources high bids are observed (due to the high probability to win a reward). However, the competition among many individuals for few resources leads to a form of specialization where only a small part of the population competes for the rewards. The majority prefers either bidding low or not at all and avoids costly competitions.

Johannes Reiter adds “In our new model we show that a shortage of resources can lead to a separation into subpopulations of competitive and unambitious individuals, and can thus contribute to speciation.” Johannes Reiter graduated in March 2015 at IST Austria with his thesis on “The Subclonal Evolution of Cancer”, and is now working as a postdoc at the Dana-Farber Cancer Institute and at Harvard University in Boston.



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