Department of Ecology, Evolution, and Behavior, University of Minnesota, , St. Paul, MN 55108, USA.
J R Soc Interface. 2013 Dec 18;11(92):20130947. doi: 10.1098/rsif.2013.0947. Print 2014 Mar 6.
Disease dilution (reduced disease prevalence with increasing biodiversity) has been described for many different pathogens. Although the mechanisms causing this phenomenon remain unclear, the disassembly of communities to predictable subsets of species, which can be caused by changing climate, land use or invasive species, underlies one important hypothesis. In this case, infection prevalence could reflect the competence of the remaining hosts. To test this hypothesis, we measured local host species abundance and prevalence of four generalist aphid-vectored pathogens (barley and cereal yellow dwarf viruses) in a ubiquitous annual grass host at 10 sites spanning 2000 km along the North American West Coast. In laboratory and field trials, we measured viral infection as well as aphid fecundity and feeding preference on several host species. Virus prevalence increased as local host richness declined. Community disassembly was non-random: ubiquitous hosts dominating species-poor assemblages were among the most competent for vector production and virus transmission. This suggests that non-random biodiversity loss led to increased virus prevalence. Because diversity loss is occurring globally in response to anthropogenic changes, such work can inform medical, agricultural and veterinary disease research by providing insights into the dynamics of pathogens nested within a complex web of environmental forces.
疾病稀释（随着生物多样性的增加，疾病的流行率降低）已在许多不同的病原体中得到描述。尽管导致这种现象的机制尚不清楚，但由于气候变化、土地利用或入侵物种等因素导致群落分解为可预测的物种亚群，这是一个重要的假设。在这种情况下，感染的流行率可能反映了剩余宿主的适应能力。为了验证这一假设，我们在北美西海岸 2000 公里范围内的 10 个地点，对一种普遍存在的一年生草本宿主进行了局部宿主物种丰度和四种广食性蚜虫传播病原体（大麦和谷类黄矮病毒）的流行率的测量。在实验室和野外试验中，我们测量了几种宿主物种上病毒感染、蚜虫繁殖力和取食偏好。随着当地宿主丰富度的下降，病毒流行率增加。群落解体是非随机的：在物种贫乏的组合中占主导地位的普遍存在的宿主，在产生蚜虫和传播病毒方面最具能力。这表明非随机的生物多样性丧失导致了病毒流行率的增加。由于人为变化导致全球范围内的多样性丧失，此类工作可以通过深入了解嵌套在复杂环境力量网络中的病原体的动态，为医学、农业和兽医疾病研究提供信息。
