Poulin R
Department of Zoology, University of Otago, Dunedin, New Zealand. robert
Int J Parasitol. 1995 Dec;25(12):1371-83. doi: 10.1016/0020-7519(95)00100-x.
Changes in host behaviour following infection with parasites are frequently reported in the literature, and are often hypothesized to be adaptive for either host or parasite. However, investigators of such phenomena often use the "adaptation" label for host behavioural changes based on their intuition and not on rigorous criteria. Alterations in host behaviour following infection can only be considered adaptive if they satisfy certain conditions: (1) they must be complex; (2) they must show signs of a purposive design; (3) they are more likely to be adaptations if they have arisen independently in several lineages of hosts or parasites; and (4) they must be shown to increase the fitness of either the host or the parasite. A survey of published examples of host behavioural changes indicates that while some are spectacularly complex and are extremely well-fitted to their presumed function, most are simple increases or decreases in an activity performed prior to infection. There are some suggestions of convergent evolution in behavioural change in distantly related host or parasite groups but more evidence is needed. Finally, most known behavioural changes have not been demonstrated to lead to fitness gains in either hosts or parasites. Few known examples satisfy more than two of the above criteria, and, in general, the adaptive function of changes in host behaviour following infection is in need of more solid proof.
文献中经常报道寄生虫感染后宿主行为的变化，并且通常假设这些变化对宿主或寄生虫具有适应性。然而，此类现象的研究者常常基于直觉而非严格标准，就将宿主行为变化贴上“适应性”标签。只有在满足某些条件时，感染后宿主行为的改变才能被视为适应性变化：（1）它们必须是复杂的；（2）它们必须表现出有目的设计的迹象；（3）如果它们在宿主或寄生虫的几个谱系中独立出现，那么它们更有可能是适应性变化；（4）必须证明它们能提高宿主或寄生虫的适应性。对已发表的宿主行为变化实例的调查表明，虽然有些变化极其复杂且与它们假定的功能高度契合，但大多数只是感染前进行的某种活动的简单增加或减少。在远缘相关的宿主或寄生虫群体的行为变化中，有一些趋同进化的迹象，但还需要更多证据。最后，大多数已知的行为变化尚未被证明能使宿主或寄生虫的适应性增加。很少有已知实例能满足上述标准中的两条以上，总体而言，感染后宿主行为变化的适应性功能需要更确凿的证据。
