Spatial variation of Daphnia parasite load within individual water bodies
Spatial variation of Daphnia parasite load within individual water bodies
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各个水体中水蚤寄生虫负荷的空间变化
DOI：
10.1093/plankt/fbr016
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发表时间：
2011
影响因子：
2.1
通讯作者：
A. Petrusek
中科院分区：
文献类型：
--
作者：
J. Wolinska;J. Seďa;Henrike Koerner;P. Šmilauer;A. Petrusek
寄生虫可以影响宿主种群动态和遗传结构，因此，研究寄生虫在宿主种群中的分布是至关重要的。研究了11个水库长刺水蚤复合种群的空间感染模式，其特征在于非生物和生物条件下的纵向梯度。我们假设，不同环境条件的网站应该有不同的感染模式。在2年的夏秋季节，我们在每个水库（上、中、下游）沿线沿着3个站位取样。分析了四组寄生虫的空间变异：原生动物Caullerya mesnili，酵母Metschnikowia sp.，微孢子虫和卵菌。微孢子虫在季节之间以及水库之间和水库内均匀分布。与之相反，C. mesnili和Metschnikowia sp.在秋季比夏季更流行，而卵菌在夏季的流行率更高。在库内尺度上，C. mesnili在水库的上游部分明显更普遍，而Metschnikowia sp.和卵菌在中部和下游地区更普遍。总之，某些水蚤寄生虫的水库内分布似乎受到环境梯度（最可能的食物丰富度和捕食压力）的影响。因此，环境异质性应考虑在未来的研究宿主-寄生虫的相互作用，即使在当地规模。
Parasites can influence host population dynamics and genetic structure; thus, it is crucial to study parasite distribution among and within host populations. We explored spatial infection patterns in Daphnia longispina complex populations from 11 reservoirs, habitats characterized by longitudinal gradients in abiotic and biotic conditions. We hypothesized that sites with different environmental conditions should have divergent infection patterns. We sampled three stations along each reservoir (upstream, middle and downstream) in the summer and autumn of 2 years. Four groups of parasites were analysed for their spatial variation: the protozoan Caullerya mesnili, the yeast Metschnikowia sp., microsporidia and oomycetes. The microsporidia were evenly distributed between seasons, as well as among- and within-reservoirs. In contrast, C. mesnili and Metschnikowia sp. were more prevalent in autumn than in summer, whereas the prevalence of oomycetes was higher in summer. On a within-reservoir scale, C. mesnili was significantly more prevalent in upstream parts of the reservoirs, whereas Metschnikowia sp. and oomycetes were more prevalent in the central and downstream areas. In summary, the within-reservoir distribution of certain Daphnia parasites seems to be affected by environmental gradients (most probably food abundance and predation pressure). Thus, environmental heterogeneity should be considered in future studies of host-parasite interactions, even on a local scale.