Aubier Thomas G, Joron Mathieu, Sherratt Thomas N
Am Nat. 2017 Mar;189(3):267-282. doi: 10.1086/690121. Epub 2017 Jan 18.
Understanding the conditions under which moderately defended prey evolve to resemble better-defended prey and whether this mimicry is parasitic (quasi-Batesian) or mutualistic (Müllerian) is central to our understanding of warning signals. Models of predator learning generally predict quasi-Batesian relationships. However, predators' attack decisions are based not only on learning alone but also on the potential future rewards. We identify the optimal sampling strategy of predators capable of classifying prey into different profitability categories and contrast the implications of these rules for mimicry evolution with a classical Pavlovian model based on conditioning. In both cases, the presence of moderately unprofitable mimics causes an increase in overall consumption. However, in the case of the optimal sampling strategy, this increase in consumption is typically outweighed by the increase in overall density of prey sharing the model appearance (a dilution effect), causing a decrease in mortality. It suggests that if predators forage efficiently to maximize their long-term payoff, genuine quasi-Batesian mimicry should be rare, which may explain the scarcity of evidence for it in nature. Nevertheless, we show that when moderately defended mimics are profitable to attack by hungry predators, then they can be parasitic on their models, just as classical Batesian mimics are.
理解中等防御性猎物演化为类似更好防御性猎物的条件，以及这种拟态是寄生性的（类贝氏拟态）还是互利性的（缪勒拟态），对于我们理解警示信号至关重要。捕食者学习模型通常预测类贝氏拟态关系。然而，捕食者的攻击决策不仅基于单纯的学习，还基于潜在的未来回报。我们确定了能够将猎物分类为不同收益类别的捕食者的最优采样策略，并将这些规则对拟态进化的影响与基于条件作用的经典巴甫洛夫模型进行对比。在这两种情况下，中等无利可图的拟态者的存在都会导致总体消耗量增加。然而，在最优采样策略的情况下，这种消耗量的增加通常会被具有模型外观的猎物总体密度的增加（稀释效应）所抵消，从而导致死亡率降低。这表明，如果捕食者有效地觅食以最大化其长期收益，真正的类贝氏拟态应该很少见，这可能解释了自然界中相关证据的稀缺性。尽管如此，我们表明，当中等防御性的拟态者对饥饿的捕食者来说是有利可图的攻击对象时，那么它们就可以像经典的贝氏拟态者一样寄生在其模型上。
