A model of coalition formation in animals
A model of coalition formation in animals
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DOI：
10.1098/rspb.1998.0548
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发表时间：
1998-11-07
影响因子：
4.7
通讯作者：
Dugatkin, LA
中科院分区：
文献类型：
--
作者：
Dugatkin, LA
提出了一个简单的三方联盟演化模型。该模型表明，在一定条件下，“赢家”和“输家”效应都有利于联盟的形成。赢家效应被定义为在时间T+1获胜的概率增加，而输家效应导致在时间T失败的情况下在时间T+1失败的概率增加。增加输家效应或赢家效应的强度或个人在等级中的地位的强度通常使联盟形成的可能性更大，而提供援助的成本增加则相反。该模型不假设任何形式的互惠，而是检查模型本身是否出现某种形式的互惠或伪互惠。当存在赢家或输家效应时，贝塔(排名第二的个体)和阿尔法(排名最高的个体)或阿尔法和伽马(排名最低的个体)之间的互惠联盟形成(例如，i帮助j对抗k，j帮助i对抗k)是可能的，但伽马和贝塔之间的互惠援助从来都不受欢迎。因此，我们得到了一个违反直觉的结果，即尽管一个等级制度中最低的两个成员之间可能会出现对抗占主导地位的个体的联盟(因为选择可能倾向于伽马辅助贝塔而不是阿尔法)，但这样的联盟并不被预测为同类互惠。考察赢家-输家效应和联盟形成的种群间比较将允许对该模型的许多最基本的预测进行测试。不幸的是，大多数关于联盟的工作都是在灵长类动物身上进行的，而关于赢家和输家效应的研究主要集中在啮齿动物上，最近在鱼类和鸟类上也是如此。希望这里提出的模型将促进未来的工作，在许多分类群中同时研究所有这些因素。
A simple three-player model is presented for the evolution of coalitions. The model demonstrates that, under certain conditions,'winner' and 'loser' effects both favour coalition formation. Winner effects are defined as an increased probability of winning at time T+1, given a victory at time T, whereas loser effects entail an increased probability of losing at time T+1, given a loss at time T. Increasing the strength of loser effects or winner effects, or the strength of an individual's position in the hierarchy, makes coalition formation in general more likely, whereas increasing the costs of giving aid does the opposite.The model does not assume any form of reciprocity but rather examines whether some form of reciprocity or pseudoreciprocity emerges from the model itself. When either winner or loser effects exist, reciprocal coalition formation (e.g. i helps j against k, and j helps i against k) between beta (second-ranked individual) and alpha (highest-ranked individual) or between alpha and gamma (lowest-ranked individual) was possible, but reciprocal aid-giving between gamma and beta was never favoured. Thus, we have the counterintuitive result that although a coalition between the two lowest members of a hierarchy against the dominant individual is possible (as selection may favour gamma aiding beta against alpha), such a coalition is not predicted to be reciprocal in kind.Interpopulational comparisons examining winner-loser effects and coalition formation would allow for a test of many of the model's most basic predictions. Unfortunately, most work on coalitions has been undertaken in primates, whereas work on winner and loser effects has focused on rodents, and more recently, in fish and birds. Hopefully, the model presented here will spur future work that will look at all of these factors simultaneously in many taxa.