Above-ground - below-ground trophic interactions

There is now emerging consensus that above-ground and below-ground compartments are intimately linked, with many examples of spatially separated organisms interacting to shape community dynamics via plant-mediated mechanisms. Research at SCRI aims to gain a mechanistic understanding of the genetic and chemical plant-mediated processes which underpin interactions between organisms that exploit different parts of the plant. By understanding these key processes, we aim to exploit natural resistance mechanisms to herbivore attack and manipulate trophic interactions to manage crop pests and maintain system stability.

We work on several systems including barley, raspberry and brassicas, focusing on how soil-dwelling herbivores (predominantly root-feeding insects) affect above-ground herbivores, their antagonists (for example, parasitoids) and plant pathogens. At present our experimental and modelling research is funded by the Scottish Government, the Natural Environmental Research Council and the Engineering and Physical Sciences Research Council. Examples of our current research include the following.Image of aphids

  • Barley: impacts of wireworms (Agriotes spp.) on bird-cherry aphid (Rhopalosiphum padi) populations via changes in plant nutritional quality.
  • Raspberry: how does root herbivory by vine weevils (Otiorhynchus sulcatus) compromise genetic resistance to the large raspberry aphid (Amphorophora idaei) above ground?
  • Brassicas: trophic cascades in a changing climate: the impact of elevated CO2 on above-below ground interactions.

For further information on this topic contact Scott Johnson.

Recent publications

Johnson, S.N., Staley, J.T., McLeod, F.A.L. and Hartley, S.E. 2010. Plant-mediated effects of soil invertebrates and summer drought on above-ground multi-trophic interactions. Journal of Ecology, (in press).

Johnson, S.N., Barton, A.T., Clark, K.E., Gregory, P.J., McMenemy, L.S. and Hancock, R.D. 2010. Elevated atmospheric CO2 impairs the performance of root-feeding vine weevils by modifying root growth and secondary metabolites. Global Change Biology (in press).

Clark, K.E., Hartley, S.E. & Johnson, S.N. 2010. Does mother know best? Parent-offspring conflict in aboveground-belowground herbivore lifecycles. Ecological Entomology, (in press).

Johnson, S.N. McNicol, J.W. 2010. Elevated CO2 and aboveground-belowground herbivory by the clover root weevil. Oecologia 162, 209-216.

Johnson, S.N., Hawes, C., Karley, A.J. 2009. Reappraising the role of plant nutrients as mediators of interactions between root- and foliar-feeding insects. Functional Ecology 23, 699-706.