Centre for Behavioural Biology, School of Veterinary Science, University of Bristol, Bristol, United Kingdom.
PLoS Comput Biol. 2011 Oct;7(10):e1002252. doi: 10.1371/journal.pcbi.1002252. Epub 2011 Oct 20.
Although social behaviour can bring many benefits to an individual, there are also costs that may be incurred whenever the members of a social group interact. The formation of dominance hierarchies could offer a means of reducing some of the costs of social interaction, but individuals within the hierarchy may end up paying differing costs dependent upon their position within the hierarchy. These differing interaction costs may therefore influence the behaviour of the group, as subordinate individuals may experience very different benefits and costs to dominants when the group is conducting a given behaviour. Here, a state-dependent dynamic game is described which considers a pair of social foragers where there is a set dominance relationship within the pair. The model considers the case where the subordinate member of the pair pays an interference cost when it and the dominant individual conduct specific pairs of behaviours together. The model demonstrates that if the subordinate individual pays these energetic costs when it interacts with the dominant individual, this has effects upon the behaviour of both subordinate and the dominant individuals. Including interaction costs increases the amount of foraging behaviour both individuals conduct, with the behaviour of the pair being driven by the subordinate individual. The subordinate will tend to be the lighter individual for longer periods of time when interaction costs are imposed. This supports earlier suggestions that lighter individuals should act as the decision-maker within the pair, giving leadership-like behaviours that are based upon energetic state. Pre-existing properties of individuals such as their dominance will be less important for determining which individual makes the decisions for the pair. This suggests that, even with strict behavioural hierarchies, identifying which individual is the dominant one is not sufficient for identifying which one is the leader.
虽然社交行为可以给个体带来许多好处，但每当社交群体成员相互作用时，也会产生一些成本。支配等级的形成可能提供了一种减少社交互动成本的方法，但等级内的个体最终可能会因他们在等级中的位置而付出不同的代价。这些不同的互动成本可能会影响群体的行为，因为当群体进行特定行为时，从属个体可能会经历与支配个体非常不同的收益和成本。在这里，描述了一个状态依赖的动态博弈，该博弈考虑了一对社会觅食者，其中在这对动物中存在着一套支配关系。该模型考虑了这样一种情况，即当从属个体与支配个体一起进行特定的行为对时，它会付出干扰成本。该模型表明，如果从属个体在与支配个体相互作用时付出这些能量成本，这会对从属个体和支配个体的行为产生影响。包括互动成本会增加个体进行的觅食行为的数量，并且行为的驱动力是从属个体。当施加互动成本时，从属个体在较长时间内会倾向于保持较轻的体重。这支持了先前的观点，即较轻的个体应该在对中充当决策者，表现出基于能量状态的领导行为。个体的预先存在的特性，如其支配地位，对于确定哪个个体为对做出决策将不那么重要。这表明，即使存在严格的行为等级，确定哪个个体是支配者也不足以确定哪个个体是领导者。
