Young Hillary S, Dirzo Rodolfo, McCauley Douglas J, Agwanda Bernard, Cattaneo Lia, Dittmar Katharina, Eckerlin Ralph P, Fleischer Robert C, Helgen Lauren E, Hintz Ashley, Montinieri John, Zhao Serena, Helgen Kristofer M
Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, California 93106.
J Parasitol. 2015 Jun;101(3):327-35. doi: 10.1645/14-684.1. Epub 2015 Jan 29.
The relative importance of environmental factors and host factors in explaining variation in prevalence and intensity of flea parasitism in small mammal communities is poorly established. We examined these relationships in an East African savanna landscape, considering multiple host levels: across individuals within a local population, across populations within species, and across species within a landscape. We sampled fleas from 2,672 small mammals of 27 species. This included a total of 8,283 fleas, with 5 genera and 12 species identified. Across individual hosts within a site, both rodent body mass and season affected total intensity of flea infestation, although the explanatory power of these factors was generally modest (<10%). Across host populations in the landscape, we found consistently positive effects of host density and negative effects of vegetation cover on the intensity of flea infestation. Other factors explored (host diversity, annual rainfall, anthropogenic disturbance, and soil properties) tended to have lower and less consistent explanatory power. Across host species in the landscape, we found that host body mass was strongly positively correlated with both prevalence and intensity of flea parasitism, while average robustness of a host species to disturbance was not correlated with flea parasitism. Cumulatively, these results provide insight into the intricate roles of both host and environmental factors in explaining complex patterns of flea parasitism across landscape mosaics.
在解释小型哺乳动物群落中跳蚤寄生率和寄生强度的变化时，环境因素和宿主因素的相对重要性尚未明确确立。我们在东非热带稀树草原景观中研究了这些关系，考虑了多个宿主层面：当地种群内的个体间、物种内的种群间以及景观内的物种间。我们从27个物种的2672只小型哺乳动物身上采集了跳蚤。共采集到8283只跳蚤，鉴定出5个属和12个物种。在一个地点的个体宿主中，啮齿动物体重和季节都影响跳蚤感染的总强度，尽管这些因素的解释力通常较弱（<10%）。在景观中的宿主种群间，我们发现宿主密度对跳蚤感染强度有持续的正向影响，而植被覆盖有负向影响。所探究的其他因素（宿主多样性、年降雨量、人为干扰和土壤性质）的解释力往往较低且不太一致。在景观中的宿主物种间，我们发现宿主体重与跳蚤寄生的患病率和强度都呈强正相关，而宿主物种对干扰的平均抵抗力与跳蚤寄生无关。总体而言，这些结果为宿主和环境因素在解释景观镶嵌体中跳蚤寄生的复杂模式时所起的复杂作用提供了见解。
