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Resource dilution effects on specialist insect herbivores in a grassland biodiversity experiment
Article first published online: 19 JAN 2005
DOI: 10.1111/j.1365-2656.2005.00913.x
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How to Cite
OTWAY, S. J., HECTOR, A. and LAWTON, J. H. (2005), Resource dilution effects on specialist insect herbivores in a grassland biodiversity experiment. Journal of Animal Ecology, 74: 234–240. doi: 10.1111/j.1365-2656.2005.00913.x
Publication History
- Issue published online: 19 JAN 2005
- Article first published online: 19 JAN 2005
- Received 7 January 2004; accepted 5 July 2004
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Keywords:
- BIODEPTH project;
- host-plant abundance;
- plant diversity;
- resource concentration;
- specialist insect herbivores
Summary
- 1The resource concentration hypothesis predicts that specialist insect herbivores attain higher loads (density per unit mass of the host-plant species) when their food plants grow in high-density patches in pure stands.
- 2We tested the resource concentration hypothesis for nine specialist insect herbivore species sampled from a field experiment where plant diversity had been manipulated experimentally, generating gradients of host-plant abundance.
- 3The specialist insects responded to varying host-plant abundance in two contrasting ways: as expected, specialist herbivore species were more likely to be present when their host-plant species were abundant; however, counter to predictions, in plots where specialists were present we found strong negative linear relationships between herbivore loads and host-plant abundances - a ‘resource dilution’ rather than concentration effect.
- 4Increased plant species-richness had an additional, but weak, negative influence on loads beyond that due to host-plant abundance.
- 5We discuss the implications of resource dilution effects for biodiversity manipulation experiments and for the study of plant–herbivore interactions more generally.