Halliday Fletcher W, Umbanhowar James, Mitchell Charles E
Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA.
Curriculum for the Environment and Ecology, University of North Carolina, Chapel Hill, NC, 27599, USA.
Ecol Lett. 2017 Oct;20(10):1285-1294. doi: 10.1111/ele.12825. Epub 2017 Sep 3.
Parasite epidemics may be influenced by interactions among symbionts, which can depend on past events at multiple spatial scales. Within host individuals, interactions can depend on the sequence in which symbionts infect a host, generating priority effects. Across host individuals, interactions can depend on parasite phenology. To test the roles of parasite interactions and phenology in epidemics, we embedded multiple cohorts of sentinel plants, grown from seeds with and without a vertically transmitted symbiont, into a wild host population, and tracked foliar infections caused by three common fungal parasites. Within hosts, parasite growth was influenced by coinfections, but coinfections were often prevented by priority effects among symbionts. Across hosts, parasite phenology altered host susceptibility to secondary infections, symbiont interactions and ultimately the magnitude of parasite epidemics. Together, these results indicate that parasite phenology can influence parasite epidemics by altering the sequence of infection and interactions among symbionts within host individuals.
寄生虫流行病可能受到共生体之间相互作用的影响，而这种相互作用可能取决于多个空间尺度上的过去事件。在宿主个体内部，相互作用可能取决于共生体感染宿主的顺序，从而产生优先效应。在宿主个体之间，相互作用可能取决于寄生虫物候。为了测试寄生虫相互作用和物候在流行病中的作用，我们将多组从带有和不带有垂直传播共生体的种子培育出的哨兵植物嵌入野生宿主种群中，并追踪了由三种常见真菌寄生虫引起的叶片感染情况。在宿主内部，寄生虫生长受到共感染的影响，但共感染常常因共生体之间的优先效应而被阻止。在宿主之间，寄生虫物候改变了宿主对二次感染的易感性、共生体相互作用，并最终影响了寄生虫流行病的规模。这些结果共同表明，寄生虫物候可以通过改变宿主个体内感染顺序和共生体之间的相互作用来影响寄生虫流行病。
