Department of Biology, University of Nevada, 1664 N Virginia street, Reno, Nevada, 89557, USA.
Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada.
Ecology. 2017 Mar;98(3):875-881. doi: 10.1002/ecy.1708.
Many host-plants exhibit genetic variation in resistance to pathogens; however, little is known about the extent to which genetic variation in pathogen resistance influences other members of the host-plant community, especially arthropods at higher trophic levels. We addressed this knowledge gap by using a common garden experiment to examine whether genotypes of Populus trichocarpa varied in resistance to a leaf-blistering pathogen, Taphrina sp., and in the density of web-building spiders, the dominant group of predatory arthropods. In addition, we examined whether variation in spider density was explained by variation in the density and size of leaf blisters caused by Taphrina. We found that P. trichocarpa genotypes exhibited strong differences in their resistance to Taphrina and that P. trichocarpa genotypes that were more susceptible to Taphrina supported more web-building spiders, the dominant group of predatory arthropods. We suspect that this result is caused by blisters increasing the availability of suitable habitat for predators, and not due to variation in herbivores because including herbivore density as a covariate did not affect our models. Our study highlights a novel pathway by which genetic variation in pathogen resistance may affect higher trophic levels in arthropod communities.
许多宿主植物在对病原体的抗性上表现出遗传变异；然而，对于病原体抗性的遗传变异在多大程度上影响宿主植物群落的其他成员，特别是更高营养级的节肢动物，人们知之甚少。我们通过使用一个共同的花园实验来解决这个知识空白，该实验旨在研究美洲黑杨（Populus trichocarpa）的基因型是否在对一种引起叶片疱状突起的病原体 Taphrina 的抗性以及在结网蜘蛛（占优势的捕食性节肢动物）的密度方面存在差异。此外，我们还研究了蜘蛛密度的变化是否可以用 Taphrina 引起的叶片疱状突起的密度和大小的变化来解释。我们发现，美洲黑杨基因型在对 Taphrina 的抗性上表现出很强的差异，而且对 Taphrina 更敏感的美洲黑杨基因型支持更多的结网蜘蛛，即占优势的捕食性节肢动物。我们怀疑这一结果是由疱状突起增加了适合捕食者的栖息地的可用性引起的，而不是由于食草动物的变化引起的，因为将食草动物密度作为协变量不会影响我们的模型。我们的研究强调了病原体抗性的遗传变异可能通过一种新的途径影响节肢动物群落中的更高营养级。
