Current address: Department of Biology, Texas A&M University, 3258 TAMU, College Station, TX 7743, U.S.A.
Effects of size structure and habitat complexity on predator–prey interactions
Article first published online: 18 NOV 2011
© 2011 The Authors. Ecological Entomology © 2011 The Royal Entomological Society
Volume 36, Issue 6, pages 744–750, December 2011
How to Cite
DELCLOS, P. and RUDOLF, V. H. W. (2011), Effects of size structure and habitat complexity on predator–prey interactions. Ecological Entomology, 36: 744–750. doi: 10.1111/j.1365-2311.2011.01324.x
- Issue published online: 18 NOV 2011
- Article first published online: 18 NOV 2011
- Accepted 13 September 2011
- Behavioural interference;
- habitat complexity;
- prey suppression;
- size structure
1. A predator's ability to suppress its prey depends on the level of interference among predators. While interference typically decreases with increasing habitat complexity, it often increases with increasing size differences among individuals. However, little is known about how variation in intrinsic factors such as population size structure alters predator–prey interactions and how this intrinsic variation interacts with extrinsic variation.
2. By experimentally varying the level of vegetation cover and the size structure of the predatory damselfly Ischnura posita Hagen, we examined the individual and interactive effects of variation in habitat complexity and predator size structure on prey mortality.
3. Copepod prey survival linearly increased as the I. posita size ratio decreased and differed by up to 31% among different predator size structures. Size classes had an additive effect on prey survival, most likely because intraspecific aggression appeared size-independent and size classes differed in microhabitat preference: large I. posita spent 14% more time foraging on the floor than small larvae and spent more time in the vegetation with increasing habitat complexity. Despite this difference in microhabitat use among size classes, habitat structure did not influence predation rates or interference among size classes.
4. In general, results suggest that seasonal and spatial variation in the size structure of populations could drive some of the discrepancies in predator-mediated prey suppression observed in nature, and this variation could exceed the effects of variation in habitat structure.