Department of Zoology, Stockholm University, 10691 Stockholm, SwedenE-mail:
Evolution. 2012 Mar;66(3):807-817. doi: 10.1111/j.1558-5646.2011.01482.x. Epub 2011 Dec 5.
In Batesian mimicry, a harmless prey species imitates the warning coloration of an unpalatable model species. A traditional suggestion is that mimicry evolves in a two-step process, in which a large mutation first achieves approximate similarity to the model, after which smaller changes improve the likeness. However, it is not known which aspects of predator psychology cause the initial mutant to be perceived by predators as being similar to the model, leaving open the question of how the crucial first step of mimicry evolution occurs. Using theoretical evolutionary simulations and reconstruction of examples of mimicry evolution, we show that the evolution of Batesian mimicry can be initiated by a mutation that causes prey to acquire a trait that is used by predators as a feature to categorize potential prey as unsuitable. The theory that species gain entry to mimicry through feature saltation allows us to formulate scenarios of the sequence of events during mimicry evolution and to reconstruct an initial mimetic appearance for important examples of Batesian mimicry. Because feature-based categorization by predators entails a qualitative distinction between nonmimics and passable mimics, the theory can explain the occurrence of imperfect mimicry.
贝氏拟态中，一种无毒性的猎物物种模仿难吃的模型物种的警示色。一个传统的建议是，拟态通过两步进化过程发生，其中一个大的突变首先实现与模型的近似相似，然后较小的变化提高相似性。然而，尚不清楚是什么方面的捕食者心理导致最初的突变体被捕食者视为与模型相似，从而留下了拟态进化的关键第一步是如何发生的问题。通过理论进化模拟和对拟态进化实例的重建，我们表明，贝氏拟态的进化可以由一个突变引发，该突变导致猎物获得一种被捕食者用作特征的特性，将潜在的猎物归类为不合适的猎物。物种通过特征突跃获得进入拟态的理论允许我们制定拟态进化过程中的事件序列的场景，并为重要的贝氏拟态实例重建初始拟态外观。因为捕食者基于特征的分类在非拟态和可通过的拟态之间产生了定性的区别，所以该理论可以解释不完全拟态的发生。
