Poulin R
Department of Zoology, University of Otago, Dunedin, New Zealand.
Parasitology. 1994;109 Suppl:S109-18. doi: 10.1017/s0031182000085127.
Parasite-induced modifications of host behaviour are known from a wide range of host-parasite associations. In many cases, these behavioural changes are thought to be adaptive and benefit the parasite by increasing its probability of successful transmission. However, in many cases, energy spent on host manipulation will not be available for other functions, such as growth. These trade-offs suggest that in the absence of other constraints, natural selection will optimize, and not maximize, the influence of parasites on host behaviour. This argument is developed and expanded into theoretical considerations of the evolution of host behaviour manipulation by parasites. Among populations of the same parasite species or among closely-related species, the optimal investment into manipulation, or optimal manipulative effort (ME*), of individual parasites is predicted to increase as (1) typical infrapopulation size decreases, (2) prevalence increases, (3) the longevity of the infected host, or of the parasite in its host, decreases, (4) passive transmission rates decrease, and (5) parasite fecundity decreases. This evolutionary analysis indicates that ecological and life history variables may have played an important role in the evolution of manipulation of host behaviour by parasites.
寄生虫诱导宿主行为改变在广泛的宿主 - 寄生虫关联中都有发现。在许多情况下，这些行为变化被认为是适应性的，通过增加成功传播的概率使寄生虫受益。然而，在许多情况下，用于操控宿主的能量将无法用于其他功能，如生长。这些权衡表明，在没有其他限制的情况下，自然选择将优化而非最大化寄生虫对宿主行为的影响。这一观点被进一步阐述并扩展为关于寄生虫操控宿主行为进化的理论思考。在同一寄生虫物种的种群之间或密切相关的物种之间，预计单个寄生虫对操控的最优投入，即最优操控努力（ME*），会随着以下情况增加：（1）典型群体内个体数量减少；（2）流行率增加；（3）受感染宿主或寄生虫在宿主体内的寿命缩短；（4）被动传播率降低；（5）寄生虫繁殖力降低。这一进化分析表明，生态和生活史变量可能在寄生虫操控宿主行为的进化中发挥了重要作用。
