Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest, H-1022, Hungary.
Department of Systematic Zoology and Ecology, Faculty of Science, Institute of Biology, Eötvös Loránd University, 1/C Pázmány Péter Sétány, Budapest, H-1117, Hungary.
Sci Rep. 2018 Jun 7;8(1):8705. doi: 10.1038/s41598-018-27103-y.
Predators influence the behaviour of prey and by doing so they potentially reduce pathogen transmission by a vector. Arthropod predators have been shown to reduce the consumption of plant biomass by pest herbivores, but their cascading non-consumptive effect on vector insects' feeding behaviour and subsequent pathogen transmission has not been investigated experimentally before. Here we experimentally examined predator-mediated pathogen transmission mechanisms using the plant pathogen Wheat Dwarf Virus that is transmitted by the leafhopper, Psammotettix alienus. We applied in situ hybridization to localize which leaf tissues were infected with transmitted virus DNA in barley host plants, proving that virus occurrence is restricted to phloem tissues. In the presence of the spider predator, Tibellus oblongus, we recorded the within leaf feeding behaviour of the herbivore using electrical penetration graph. The leafhopper altered its feeding behaviour in response to predation risk. Phloem ingestion, the feeding phase when virus acquisition occurs, was delayed and was less frequent. The phase when pathogen inoculation takes place, via the secretion of virus infected vector saliva, was shorter when predator was present. Our study thus provides experimental evidence that predators can potentially limit the spread of plant pathogens solely through influencing the feeding behaviour of vector organisms.
捕食者会影响猎物的行为，从而有可能通过媒介减少病原体的传播。已经证明节肢动物捕食者会减少害虫草食动物对植物生物量的消耗，但它们对媒介昆虫取食行为的级联非消耗性影响以及随后的病原体传播尚未在实验中进行过研究。在这里，我们使用由叶蝉 Psammotettix alienus 传播的植物病原体小麦矮化病毒，通过实验来检验捕食者介导的病原体传播机制。我们应用原位杂交技术来定位在大麦宿主植物中哪些叶片组织感染了传播的病毒 DNA，证明病毒的发生仅限于韧皮部组织。在蜘蛛捕食者 Tibellus oblongus 的存在下，我们使用电穿透图记录了食草动物在叶片内的取食行为。叶蝉改变了其取食行为以应对捕食风险。取食期（病毒获取发生的阶段）被延迟且发生频率降低。当捕食者存在时，通过受感染的媒介昆虫唾液分泌进行病原体接种的阶段更短。因此，我们的研究提供了实验证据，表明捕食者仅通过影响媒介生物的取食行为就有可能限制植物病原体的传播。
