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Professor William O.C. Symondson

Professor William O.C. Symondson


School of Biosciences

+44 (0)29 2087 5151
+44 (0)29 2087 4116
Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX


Research overview

My main interest and expertise is in the trophic interactions between predators and prey, herbivores and plants, and the effects of these interactions on communities. The context may be answering questions with applied outcomes (crop ecology) or conservation (saving rare species) from extinction. Applied contexts include control by natural enemies of major pests such as aphids and slugs in cereal crops (biocontrol). We can now go beyond that to analyse how nutrient-specific foraging by the predators allow us to model the interactions and predict whether they are likely to lead to pest suppression. We look at how birds, such as thrushes, respond to landscape complexity and exploit patchy landscapes. We develop have developed models that allow us to measure overall prey choice.   

In the conservation field we are looking, for example, at how an alien analogue species (giant Aldabran tortoises) can help to restore ecosystem function on a Mauritian island where native tortoises have become extinct. To do this we had to barcode all the plant species on the island. Having done that we can now quickly analyse herbivory (of both native and alien plants) by other herbivores as well (lizards, invasive ants). 

In Europe we are interested in how global climate change may affect competition within a community. Using latitude as an analogue for climate change we analysed diet and competition between reed bed warblers on a transect from northen England to Spain. We examined the diet of Turtle Doves, one our fastest declining species, both in Northern Europe and on their wintering grounds in Senegal. Previous work had shown that diet compostion affected the fitness of chicks and adults. Here we looked at how different dietary elements correlated with different pathogenic and non--pathogenic strains of the parasite Trichomonas gallinae.

In a range of studies we have used molecular diagnostics to analyse trophic metrics, ranging from microarthropods feeding on slug parasitic nematodes to giant tortoises acting as keystone species modifying plant communities.














Professor of Molecular Ecology, Cardiff University.

Reader in Molecular Ecology, Cardiff University.

Senior Lecturer in Molecular Ecology, Cardiff University.

Lecturer in Molecular Ecology (full tenure) Cardiff University.

Head of Invertebrate Molecular Ecology Facility (antibodies) and Lecturer, Cardiff Univ.

Lecturer and Research Associate, Cardiff University.

Postdoc Research Associate, Cardiff University.

Ph.D. in Invertebrate Ecology, School of Pure & Applied Biology, Cardiff.

Research Assistant at Cleppa Park Field Station, Cardiff University

Assistant Curator of Entomology at the NationalMuseum of WalesCardiff

Diploma in Environmental Management

Self-employed farmer.
























From October 2020 I semi-retired and am no longer involved with teaching.

My interest is in the dynamics of predator-prey interactions involving generalist predators and  herbivores. The choices made by such predators are complex and the result of interactions between a range of spatial and temporal biotic and abiotic factors. Given the limitations of laboratory-based prey choice experiments we concentrate instead on developing techniques for measuring the strengths of trophic interactions directly in the field. We were amongst the first to realise the potential of PCR to amplify prey DNA from field-caught predators and are at the forefront of developments in this field.  Initially we developed multiplex systems to analyse each predator for multiple prey targets in a single PCR step. We were amongst the first to use High Throughput Sequencing to look at complete diets of vertebrates and invertebrates in the field. 

Current and recent projects and areas of continued interest

  • A phylogenetic analysis of common earthworm species revealing extraordinary levels of cryptic diversity, plus development of molecular markers for different lineages/species of earthworm to track predation on them by invertebrate and vertebrate predators.
  • Analysis of interception by predators of vibrational sexual communication signals between planthoppers and confirmation of predation in the field using molecular diagnostics (with the National Institute of Biology, Ljubljana).
  • Analysis of prey choice and intraguild predation in arable crops, involving particularly carabid beetles and spiders.
  • Development and application of novel software, EcoNullNetR, to analyse prey choice.
  • Competition between the alien Asian Musk Shrew and the rare Telfair's Skink on a Mauritian island.
  • Analysis of herbivory by giant tortoises introduced as an analogue species to restore ecosystem function on a Mauritian island. All plant species barcoded.
  • Analysis of the diets of birds (seabirds and rare terrestrial species).
  • Analysis of the diets of bats in temperate and tropical habitats.
  • Analysis of food webs in farmland: a) in rivers running through intensive vs. extensive farming systems; b) exploitation of patchy landscapes by farmland birds (with BTO).
  • Analysis of the diets of British reptiles.
  • The introgression of alien species into terrestrial foodwebs.
  • Interactions between disease and diet.

Most of the project areas above involve the use of High Throughput Sequening or other molecular diagnostics.

I also have a particular interest in slugs and their natural enemies.

Advice on slug control in the garden

Current staff

PhD students (current and recent)

  • Mr Maximillian Tercel (analysis of the effects of invasive ants on native invertebrate communities on Round Island, Mauritius)
  • Mr Ewan Stenhouse (relationship between diet and the distribution of Hawfinches across the UK and Europe)
  • Ms Rebecca Young (diet of the Turtle Dove and interactions with Trichomonas iinfection)
  • Ms Sarah Davies (predicting the effects of global climate change on dietary competition between reed bed warblers across Europe)
  • Dr Lorna Drake (analysis of the diets of otters across England and Wales)
  • Dr Jordan Cuff (analysis of nutrient-specific foraging by spiders in the field)
  • Dr Jennifer Stockdale (Using environmental genomics to track habitat use by birds exploiting heterogeneous landscapes)

Grant awarding bodies

Current funding

  • Natural Environment Research Council
  • Malaysian Government
  • Biotechnology and Biological Sciences Research Council
  • Royal Society for the Protection of Birds
  • Durrell Wildlife Conservation Trust
  • KESS - Knowledge Economy Skills Studentships Welsh Government)

Current and recent collaborations

  • Durrell Wildlife Conservation Trust
  • Mauritian Wildlife Foundation
  • National Institute of Biology, Ljubljana, Slovenia
  • University of Barcelona, Spain
  • National Museum of Wales, Cardiff
  • University of Bristol
  • University of Sussex
  • University of Nottingham
  • Institute of Arable Crops Research, Rothamsted
  • Masaryk University, Brno, Czech Republic
  • Queen Mary, University of London
  • University of Cork
  • Ohio State University