Resource dilution effects on specialist insect herbivores in a grassland biodiversity experiment
Article first published online: 19 JAN 2005
Journal of Animal Ecology
Volume 74, Issue 2, pages 234–240, March 2005
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
- Issue published online: 19 JAN 2005
- Article first published online: 19 JAN 2005
- Received 7 January 2004; accepted 5 July 2004
- BIODEPTH project;
- host-plant abundance;
- plant diversity;
- resource concentration;
- specialist insect herbivores
- 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.