Multi-Trophic Interactions

Photograph of a beetle on chicory flowerMulti-trophic Interactions is a new major research topic in Agroecology that combines existing lines of study at both SCRI and the University of Dundee. Trophic (or feeding) interactions drive the cycling of energy and nutrients in farmland. Insects and other invertebrates feed on plants and in turn are fed on by other insects, spiders, various symbionts, pathogens and vertebrates. A very small proportion of the total species in trophic interactions are pests of agriculture. Most mediate processes that are essential to the cropping cycle, such as the breakdown of dead organisms (crops, weeds, wood, animals), the regulation of pests and the pollination of flowers. These trophic interactions are exceedingly complex and are studied using advanced concepts and methods in organism biology, molecular biology and mathematical modelling.  Through gaining basic knowledge, the topic aims to provide a scientific basis for future management of invertebrate populations in farmland.

Research projects

In Multi-trophic Interactions, we examine the basic processes through which energy and matter are transferred among plants, invertebrates (mainly insects), symbionts and pathogens. Our research concentrates on the whole organism, ranging from genome to field, using expertise in plant and invertebrate population dynamics, plant nutrition and defence, mathematical modelling, taxonomy, microscopy and molecular biology. The topic has four current project areas:

  • above ground-below ground interactions
  • plant mechanisms in herbivory
  • insects, symbionts, disease
  • trophic modelling.

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Latest papers and reports 

Karley, A.J., Hawes, C., Iannetta, P.P.M., Squire, G.R. 2008. Intraspecific variation in Capsella bursa-pastoris in plant quality traits for insect herbivores. Weed Research 48, 147-156.

Hawes, C., Haughton, A.J., Bohan, D.A.,  Squire, G.R. 2008. Functional approaches for assessing plant and invertebrate abundance patterns in arable systems. Basic and Applied Ecology (doi:10.1016/j.baae.2007.11.007).

Johnson, S.N., Zhang, X., Crawford, J.W., Gregory, P.J., Young, I.M. 2007. Egg hatching and survival time of soil-dwelling insect larvae: a partial differential equation model and experimental validation. Ecological Modelling 202, 493-502.

Zhang, X., Johnson, S.N., Crawford, J.W., Gregory, P.J., Young, I.M. 2007. A general random walk model for the leptokurtic distribution of organism movement: theory and application. Ecological Modelling 200, 79-88

Johnson, S.N., Crawford, J.W., Gregory, P.J., Grinev, D.V., Mankin, R.W., Masters, G.J., Murray, P.J., Wall, D.H., Zhang, X. 2007. Non-invasive techniques for investigating and modeling root-feeding insects in managed and natural systems. Agricultural and Forest Entomology 9, 39-46.

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Applications and extension

Scientific papers and meetings The findings and recommendations of all our research in trophic interactions are published as scientific papers in international, peer-reviewed journals such as Basic and Applied Ecology, Bulletin of Entomological Research, Ecological Modelling, Philosophical Transactions of the Royal Society B. and Weed Research. Members of the group regularly give invited presentations on trophic interactions at international scientific meetings, including recently the International Congress of Entomology at Durban, South Africa. members of the group recently organised a special topic on 'Multi-trophic interactions from genome to field' at the meeting of the British Ecological Society in London, 3-5 September 2008. 

Research students Most of the doctoral students in the group are supervised by research staff in Multi-trophic Interactions. We have current PhD projects in trophic modelling, insect population dynamics, insects and their secondary symbionts and insects-disease relations.

Underpinning landscape-scale research The more fundamental studies in multi-trophic interactions provide a scientific basis for the Agroecology group's research at scales of the field and landscape where we develop models and decision aids to improve the ecological integrity and biodiversity of arable-grass production systems.  For example, the basic knowledge of plant-pest-predator interactions enabled us to construct and populate a tri-trophic model designed to assess the effects of insect-resistant crops on non-target organisms.

Advice to UK government departments and NGOs The findings in our research inform policy and practice on farmland biodiversity by Department of the Environment, Food and Rural Affairs (Defra) and the Scottish Government, and NGOs such as the Game and Wildlife Conservation Trust (GWCT) and Linking Environment and Farming (LEAF).

Teaching and training: the Living Field project The findings of our research in this topic contribute much of the source material for the Living Field, SCRI's education and outreach project aimed at schools and the public.  

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