Department of Wildlife, Fish and Conservation Biology, University of California, Davis, Davis, CA, USA,
Oecologia. 2013 Nov;173(3):1009-22. doi: 10.1007/s00442-013-2664-1. Epub 2013 May 1.
The distribution of parasites among individual hosts is characterised by high variability that is believed to be a result of variations in host traits. To find general patterns of host traits affecting parasite abundance, we studied flea infestation of nine rodent species from three different biomes (temperate zone of central Europe, desert of Middle East and tropics of East Africa). We tested for independent and interactive effects of host sex and body mass on the number of fleas harboured by an individual host while accounting for spatial clustering of host and parasite sampling and temporal variation. We found no consistent patterns of the effect of host sex and body mass on flea abundance either among species within a biome or among biomes. We found evidence for sex-biased flea infestation in just five host species (Apodemus agrarius, Myodes glareolus, Microtus arvalis, Gerbillus andersoni, Mastomys natalensis). In six rodent species, we found an effect of body mass on flea abundance (all species mentioned above and Meriones crassus). This effect was positive in five species and negative in one species (Microtus arvalis). In M. glareolus, G. andersoni, M. natalensis, and M. arvalis, the relationship between body mass and flea abundance was mediated by host sex. This was manifested in steeper change in flea abundance with increasing body mass in male than female individuals (M. glareolus, G. andersoni, M. natalensis), whereas the opposite pattern was found in M. arvalis. Our findings suggest that sex and body mass are common determinants of parasite infestation in mammalian hosts, but neither of them follows universal rules. This implies that the effect of host individual characteristics on mechanisms responsible for flea acquisition may be manifested differently in different host species.
寄生虫在个体宿主中的分布具有高度的可变性，这种可变性被认为是宿主特征变化的结果。为了找到影响寄生虫丰度的宿主特征的一般模式，我们研究了来自三个不同生物群落（中欧温带、中东沙漠和东非热带）的九种啮齿动物物种的跳蚤感染情况。我们测试了宿主性别和体重对个体宿主携带的跳蚤数量的独立和交互影响，同时考虑了宿主和寄生虫采样的空间聚类和时间变化。我们没有发现宿主性别和体重对生物群落内或生物群落间的跳蚤丰度有一致的影响模式。我们仅在五个宿主物种（A. agrarius、M. glareolus、M. arvalis、G. andersoni 和 M. natalensis）中发现了跳蚤感染存在性别偏向的证据。在六种啮齿动物物种中，我们发现了体重对跳蚤丰度的影响（上述所有物种和 M. crassus）。这种影响在五种物种中为正，在一种物种（M. arvalis）中为负。在 M. glareolus、G. andersoni、M. natalensis 和 M. arvalis 中，体重和跳蚤丰度之间的关系受宿主性别调节。这表现在雄性个体的跳蚤丰度随体重增加而变化更为陡峭（M. glareolus、G. andersoni、M. natalensis），而在 M. arvalis 中则相反。我们的研究结果表明，性别和体重是哺乳动物宿主寄生虫感染的常见决定因素，但它们都没有遵循普遍的规律。这意味着宿主个体特征对获得跳蚤机制的影响可能在不同的宿主物种中表现不同。
