Present address: Genetics, Ecology and Evolution Group, Institute of Integrative and Comparative Biology, University of Leeds, Leeds LS2 9JT, UK.
The reaction norm of size and age at maturity under multiple predator risk
Article first published online: 27 MAY 2010
© 2010 The Authors. Journal compilation © 2010 British Ecological Society
Journal of Animal Ecology
Volume 79, Issue 5, pages 1069–1076, September 2010
How to Cite
Beckerman, A. P., Rodgers, G. M. and Dennis, S. R. (2010), The reaction norm of size and age at maturity under multiple predator risk. Journal of Animal Ecology, 79: 1069–1076. doi: 10.1111/j.1365-2656.2010.01703.x
- Issue published online: 5 AUG 2010
- Article first published online: 27 MAY 2010
- Received 29 October 2009; accepted 2 April 2010 Handling Editor: John Fryxell
- age at maturity;
- Daphnia pulex;
- development rate;
- growth rate;
- predation risk;
- probabilistic reaction norm;
- size at maturity
1. Two major theories underpin our understanding of how predation risk shapes life history. The first is centred around predator induced changes in activity that subsequently reduce food intake and thus growth. The second is centred around size selective, predator induced changes in development.
2. Here, we challenge these theories using experiments and probabilistic models of maturation reaction norms to investigate predator induced life history in the water flea Daphnia pulex facing two different predators.
3. We combine this reaction norm investigation with an assessment of growth rate, development rate, moult number and moult duration to uncover the mechanisms controlling predator induced life history plasticity when D. pulex face either large or small size selective predators.
4. The probabilistic reaction norms reveal predator specific norms of reaction in size and age along a food gradient. Fish cues reduce age and size, with a bias in age, and do so by reducing moult number and duration. Midge cues increase age and size, with a bias in size, and do so by fine scale modulation of early growth rates.
5. These data contribute towards developing a unified view of how predation risk from multiple predators shapes life history evolution.