Pough F H, Brower L P, Meck H R, Kessell S R
Cornell University, Ithaca, New York 14850.
Proc Natl Acad Sci U S A. 1973 Aug;70(8):2261-5. doi: 10.1073/pnas.70.8.2261.
We previously explored automimicry assuming that a species of prey was so unpalatable as to promote conditioned avoidance for a period of time after a predator encountered a single individual (Case 1). In this paper, we assume that the prey is less noxious and that two encounters are required. Case 2 allows the two encounters with unpalatables to be separated by any number of palatables, while in Case 3 the predator must encounter two unpalatables, consecutively.The general relationships in the three cases are similar, but the automimetic advantage is reduced moderately in Case 2 and greatly in Case 3. To attain the same automimetic advantage as in Case 1 requires an increase in the proportion of unpalatables, or in the induced rejection period, or both. Consequently, selection will tend to increase the unpalatability so that Cases 2 and 3 converge to Case 1.Species that are uniformly and highly unpalatable can afford to be more dispersed than automimetic species. Case-2 and -3 automimetic species will benefit greatly from gregariousness, while in Case-1 automimicry situations this is less important.
我们之前探讨了自拟态现象，假设某一猎物的味道非常难吃，以至于捕食者在遇到单个个体后的一段时间内会形成条件性回避（情况1）。在本文中，我们假设猎物的毒性较小，且需要两次接触。情况2允许与难吃的猎物的两次接触被任意数量的可口猎物隔开，而在情况3中，捕食者必须连续遇到两个难吃的猎物。三种情况下的一般关系相似，但自拟态优势在情况2中适度降低，在情况3中大幅降低。要获得与情况1相同的自拟态优势，需要增加难吃猎物的比例，或延长诱导性拒食期，或两者兼而有之。因此，自然选择将倾向于增加难吃程度，从而使情况2和情况3趋近于情况1。味道始终难吃且难吃程度高的物种比自拟态物种能够分布得更分散。情况2和情况3的自拟态物种将从群居习性中大大受益，而在情况1的自拟态情形中，群居习性的重要性较低。
