The effect of multiple host species on a keystone parasitic plant and its aphid herbivores

Jennifer K. Rowntree, David Fisher Barham, Alan J A Stewart, Sue E. Hartley*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Summary: The exploitation of shared resources by diverse organisms underpins the structure of ecological communities. Hemiparasitic plants and the insect herbivores feeding on them both rely, directly and indirectly, on the resources supplied by the parasite's host plant. Therefore, the identity and number of host plant species providing these resources is likely to be critical for parasite and herbivore performance. We tested the effect of single and multiple host species on the biomass of the generalist parasitic plant Rhinanthus minor and the abundance of its aphid (Aphis gossypii) herbivores. Parasite biomass was proportional to the number of haustorial connections to host roots and was determined by host species identity rather than host functional group. Host species identity was also an important influence on aphid population size, and parasites attached to Lotus corniculatus experienced a considerable reduction in aphid herbivory. The effects on the parasite attaching to multiple hosts depended on the combination of species present. However, host mixtures generally benefitted aphids by diluting the negative effects of particular host species. Our findings suggest that the specificity of host attachment alters the impact of this keystone parasitic plant on its own herbivores and, potentially, on the wider plant and herbivore community.

Original languageEnglish
Pages (from-to)829-836
Number of pages8
JournalFunctional Ecology
Issue number4
Early online date12 Jul 2014
Publication statusPublished - Aug 2014


  • Aphis gossypii
  • Direct and indirect effects
  • Herbivory
  • Lotus corniculatus
  • Mixed hosts
  • Rhinanthus minor

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