Population and community dynamics

Aphids typically share their host plant with no or only a few other species of aphids and hence the scope for direct or exploitation competition within the aphid community is limited. However, they do share natural enemies and hence may interact through apparent competition mediated by the higher rather than the lower trophic level. At Imperial College we studied for ten years* an aphid community building quantitative food webs to assess the potential for indirect effects, and then carried out experiments in the field and laboratory to test whether they were present. We continue to be interested in both trophic-mediated and trait-mediated indirect effects, and in using the experience we have built up with pea aphids, its natural enemies and their alternate hosts, to design experiments to explore their importance in structuring insect communities.

*The food web project was masterminded for the first five years by Christine Müller who very sadly died in March 2008, and in the second five years by Frank van Veen who is now at the University of Exeter.

Selected publications

  • Jones, T.S., Godfray, H.C.J. & van Veen, F.F.J. 2009 Resource competition and shared natural enemies in experimental insect communities. Oecologia 159, 627- 625.
  • van Veen, F.F.J., Brandon, C.B. & Godfray, H.C.J. 2009 A positive trait-mediated indirect effect involving the natural enemies of competing herbivoresOecologia 160, 195-205.
  • van Veen, F.J.F., Müller, C.B., Cooke, R., Pell, J. & Godfray, H.C.J. 2008 Food web structure of three guilds of natural enemies: predators, parasitoids and pathogens of aphids.  Journal of Animal Ecology 77, 191-200.
  • Ives, A.R. & Godfray, H.C.J. 2006 Phylogenetic analysis of trophic associations. American Naturalist 168, E1-E14 (0003-0147/2006/16801-41209).
  • van Veen, F.J., Morris, R.J. & Godfray, H.C.J. 2006 Apparent competition, quantitative food webs and the structure of phytophagous insect communitiesAnnual Review of Ecology & Systematics 51, 187-208.
  • van Veen, F.J., van Holland, P.D. & Godfray, H.C.J. 2005. Stable coexistence in experimental insect communities due to an interaction of density-mediated and trait-mediated indirect effects. Ecology 86, 3182-3189.
  • Cohen, J.E., Jonsson, T., Müller, C.B., Godfray, H.C.J. & Savage, V.M. 2005 Body sizes of hosts and parasitoids in individual feeding relationships. Proceedings of the National Academy of Science 102, 684-689.
  • van Veen, F.J.F., Müller, C.B., Adriaanse, I.C.T. & Godfray H.C.J. 2002 Spatial heterogeneity in risk of secondary parasitism in a natural population of an aphid parasitoid. Journal of Animal Ecology 71, 463-469.
  • Pope, T., Croxson, E., Pell, J.K., Godfray H.C.J. & Müller, C.B. 2002 Apparent competition between two species of aphid via the fungal pathogen Erynia neoaphidis and its interaction with the aphid parasitoid Aphidius ervi. Ecological Entomology 27, 196-203.
  • van Veen, F.J.F., Rajkumar, A., Müller, C.B. & Godfray, H.C.J. 2001 Increased reproduction by pea aphids in the presence of secondary parasitoids. Ecological Entomology 26, 425-429.
  • Morris, R.J., Müller, C.B. & Godfray, H.C.J. 2001 Field experiments testing for apparent competition between primary parasitoids mediated by secondary parasitoids. Journal of Animal Ecology 70, 301-309.
  • Müller, C.B., Adriaanse, I.C.T., Belshaw, R. & Godfray, H.C.J. 1999 The structure of an aphid-parasitoid community. Journal of Animal Ecology 68, 346-370.