Article: http://www.americanscientist.org/template/AssetDetail/assetid/15654/page/1

 Evolution is the governing force in nature driving change towards more suitable strategies by animals to their environments. Evolutionary game theory is extremely useful when analyzing the strategies utilized by animals in animal contests - whereby two animals in an encounter can choose different strategies based on their ecotype (habitat), information structure, and pattern of interaction (determination of reward based on player’s strategies). These stable strategies are those that will allow the animal to fare best in these contests and thus will be the strategy passed down onto their offspring.

Most animal contests are viewed under the general lens of the players (animals) assessing their own, as well as their opponent’s strengths and weaknesses based on some measure of physical prowess in addition to other factors such as whether a territory under dispute is owned or is being intruded by that player. However, many paradoxes arise under this broad view. How does one explain a threat by an animal if that threat increases the vulnerability of the signaler, why some animals will actually elect to leave a territory they own when faced with an intruder, or why in some cases fight time does not correlate negatively with the size difference between fighting animals? One can assume these are simply what they appear to be - paradoxes that don’t fit into the general game assigned to animal contests. However, more insightful is the approach that perhaps there are many different, coexisting games that provide a reward structure under which the actions witnessed are actually the most evolutionary stable strategies.

The paradoxes described above are explained in detail within the article. These specific examples were chosen because they represent evolutionary stable strategies in games different than those generally assumed to cover the whole of animal contests. Each of these games is, of course, subject to environmental conditions. For example, when damselflies engage each other, it is seen that the other damselfly’s size does not enter into the other player’s decision to engage in a contest. Rather, it seems to be that each fly assesses their own reserves, and then values winning as proportional to the potential remaining reserves. The environmental conditions in this case would involve a coefficient of variation, which defines the dispersion of energy reserves about their mean, and a cost/benefit ration, which compares “reproductive cost of a spent unit of fat reserves to the eventual winner’s reproductive benefit from a saved unit. Similar techniques for describing other “paradox” situations are applied in this manner within the article (some pretty explanatory graphs are even included).

In class we have discussed simple games, such as the prisoners’ dilemma and the penalty kicks in professional soccer. However, when analyzing games in the natural world, it is often that the governing dynamics are not as clear. It seems that though often one type of game may work in general, the exceptions to the game may actually be examples of entirely different games played under different parameters. Much time and effort must go into not only defining the payoffs from a game, but the actual conditions and parameters that define each game so that an observer can be sure they are analyzing a contest in the correct manner (though testing these predictions is extremely difficult).