Spread of parasites in metapopulations: an experimental study of the effects of host migration rate and local host population size
Spread of parasites in metapopulations: an experimental study of the effects of host migration rate and local host population size
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DOI：
10.1017/s0031182004006602
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发表时间：
2005-03-01
期刊：
影响因子：
2.4
通讯作者：
Wade, MJ
中科院分区：
文献类型：
--
作者：
Lopez, JE;Gallinot, LP;Wade, MJ
我们建立了实验集合种群的面粉甲虫，赤拟谷盗，其体外寄生螨，Acarophenax tribolii，探讨主机迁移率和当地的主机人口规模上的螨感染的传播的影响。在我们的集合种群的全球患病率不到一半，观察到的斑块内患病率，使空间结构本身提供了很大的保护主机免受寄生虫感染。我们的研究结果进一步表明，迁移发挥了决定性的作用，在一个集合种群内感染的补丁的数量，而主机的人口规模发挥了决定性的作用，在当地的患病率，感染的主机在当地补丁的分数。地方和全球流行率似乎在两个不同的时间尺度上达到平衡水平。当地宿主流行率在接受受感染的宿主移民后30天内达到平衡值。全球流行率增长缓慢，明显依赖于占用率，即至少有1个受感染主机的主机补丁数量，而这又取决于主机补丁之间的主机迁移水平。人口规模的影响并不限于当地的患病率在没有空间结构的补丁，但扩展到集的补丁在集合种群。劳埃德的斑块指数显着不同的集合种群与大量的主机。虽然寄生虫聚集在主机上的本地补丁大小，他们往往聚集到一个更大的程度上在较小的主机补丁大小。我们讨论我们的实证研究结果，根据目前的流行病学理论。
We established experimental metapopulations of the flour beetle, Tribolium castaneum, and its ectoparasitic mite, Acarophenax tribolii, to investigate the effects of host migration rate and local host population size on the spread of mite infections. Global prevalence across our metapopulations was less than half the observed within-patch prevalence, so that spatial structure alone afforded a great deal of protection to hosts against parasite infection. Our results showed further that migration played a determining role in occupancy, the number of patches infected within a metapopulation, while host population size played a determining role in local prevalence, the fraction of hosts infected within local patches. Local and global prevalence appeared to reach equilibrium levels on 2 different time-scales. Local host prevalence reached equilibrium values within 30 days of receiving an infected host migrant. Global prevalence increased more slowly and was clearly dependent upon occupancy, the number of host patches with at least 1 infected host, which in turn depended on the level of host migration among host patches. The effect of population size was not limited to local prevalence in patches without spatial structure but extended to sets of patches across the metapopulation. Lloyd's index of patchiness differed significantly between metapopulations with small versus large numbers of hosts. Although parasites were aggregated on hosts for both local patch sizes, they tended to aggregate to a much greater degree at the smaller host patch size. We discuss our empirical findings in light of current epidemiological theory.