Département des sciences biologiques, Université de Montréal, Montréal, Canada.
Proc Biol Sci. 2019 Aug 14;286(1908):20191323. doi: 10.1098/rspb.2019.1323. Epub 2019 Aug 7.
Individuals from the same population typically show consistent differences in behavioural traits that are frequently associated with differences in contextual plasticity. Yet such a correlation might arise either because some individuals are better able than others to detect environmental changes or because the benefits of being plastic are condition-dependent. To discriminate between these two competing hypotheses, I developed an individual-based model that simulates a population in which individuals of varying fighting ability compete by pairwise interactions using either the fixed hawk (aggressive) or dove (peaceful) strategies or a conditional assessment strategy. As anticipated, the model predicts that only individuals with low (and/or intermediate) fighting ability should use the assessment strategy, giving rise to a negative (or dome-shaped) relationship between aggressiveness and plasticity. The proportion of plastic individuals, however, should be affected not only by the environmental conditions in which individuals live but also by the mechanism that would maintain variation in the traits that determine the benefits of plasticity. In particular, if individual differences in fighting ability may be eroded by natural selection, it predicts that ecological conditions that cause assortative interactions (e.g. high predation risks) would contribute in maintaining variation among individuals in their fighting ability, thereby favouring greater plasticity.
来自同一群体的个体通常表现出行为特征的一致差异，这些差异通常与环境可塑性的差异有关。然而，这种相关性可能是因为一些个体比其他个体更能察觉环境变化，也可能是因为具有可塑性的好处是条件依赖性的。为了在这两种相互竞争的假设之间做出区分，我开发了一个基于个体的模型，该模型模拟了一个群体，其中具有不同战斗能力的个体通过两两相互作用使用固定的鹰（攻击性）或鸽（和平性）策略或条件评估策略进行竞争。正如预期的那样，该模型预测只有低（和/或中等）战斗能力的个体才应该使用评估策略，从而导致攻击性和可塑性之间呈负（或圆顶形）关系。然而，具有可塑性的个体的比例不仅受到个体所处的环境条件的影响，还受到决定可塑性好处的特征的差异的维持机制的影响。特别是，如果战斗能力的个体差异可能受到自然选择的侵蚀，那么它预测会导致个体之间发生趋同相互作用（例如高捕食风险）的生态条件将有助于维持其战斗能力的个体之间的变异，从而有利于更大的可塑性。
