Depth selection and life history strategies as mutually exclusive responses to risk of fish predation in Daphnia
- 171 Downloads
We tested if pelagic crustaceans of the genus Daphnia use different anti-predator defences in environmental conditions that do or do not offer deep refuge from planktivorous fish. We kept Daphnia catawba in two series of 9-m deep enclosures with and without caged cyprinid fish Phoxinus eos. In one series of enclosures, Daphnia could select its depth of residence and hide in deep dark water layers to avoid anticipated fish predation, while in another series of enclosures, a plankton net barrier fixed at 2-m depth forced them to stay in subsurface zone exposed to fish kairomones. We compared depth residence and migratory behaviour strategies with life history strategies (body size and size at first reproduction, diapause induction) in Daphnia exposed or not to fish kairomones with or without deep refuge. In deep enclosures with fish, Daphnia spent daytime hours in deep dark layers while at night, they resided closer to the water surface. Yet, no change in life history parameters of migrating individuals was observed compared to the fish-free conditions. In enclosures with fish, where the net barrier forced Daphnia to reside in subsurface zone, they produced smaller offspring, matured at smaller size and achieved lower maximum body length compared to the fish-free conditions. However, they did not produce diapausing eggs. Our experimental study supports the hypothesis that diel vertical migration behaviour with daytime residence in deep, dark water are the preferred antipredator strategy chosen by Daphnia facing anticipated fish predation over life history changes such as reduced size and low growth rate which are used when dark deep refuge is not present or accessible.
KeywordsDaphnia Alternative antipredator strategies Depth selection Life history
This study was financed through grants from the Natural Sciences and Engineering Research Council of Canada (Discovery Grant) and from the Québec Ministry of Education (FQRNT: Team Grant) to B.P.A. and by a post-doctoral fellowship to M.S. and a scholarship grant to M.G. from the GRIL (Groupe de Recherche Interuniversitaire en Limnologie et en Environnement Aquatique, Université de Montréal). We thank Nicholas Tzouannis, Alexandra Rutherford, Malorie Gélinas and G. Méthot for field assistance. We thank Anas Ghadouani for valuable comments and English tuning on the manuscript. The study was presented as a poster at the VIIIth international symposium on Cladocera, 21–25 October 2008, Aguascalientes, Mexico.
- Dawidowicz, P. & C. J. Loose, 1992. Metabolic costs during predator-induced diel vertical migration in Daphnia. Limnology and Oceanography 37: 665–669.Google Scholar
- De Meester, L., 1994. Life histories and habitat selection in Daphnia: divergent life histories of D. magna clones differing in phototactic behaviour. Oecologia 97: 333–341.Google Scholar
- De Meester, L., & J. Pijanowska, 1996. On the trait-specificity of the response of Daphnia genotypes to the chemical presence of a predator. In Lenz, P. H., D. K. Hartline, J. E. Purcell, & D. L. Macmillan (eds), Zooplankton: Sensory Ecology and Physiology. Gordon and Breach, Amsterdam: 407–417.Google Scholar
- De Meester, L., P. Dawidowicz, E. van Gool & C. J. Loose, 1999. Ecology and evolution of predator-induced behaviour of zooplankton: depth selection behaviour and diel vertical migration. In Tollrian, R. & D. Harvell (eds), Ecology and Evolution of Inducible Defenses. Princeton University Press, Princeton, NJ: 160–176.Google Scholar
- Fiksen, Ø., 1997. Allocation patterns and diel vertical migration: modelling the optimal Daphnia. Ecology 78: 1446–1456.Google Scholar
- Lampert, W., 1993. Ultimate causes of diel vertical migration of zooplankton: new evidence for the predator avoidance hypothesis. Archiv für Hydrobiologie Beihefte Ergebnisse der Limnologie 39: 79–88.Google Scholar
- Ślusarczyk, M., 2004. Environmental plasticity of fish avoidance diapause response in Daphnia magna. Journal of Limnology 63(Suppl 1): 70–74.Google Scholar
- Ślusarczyk, M., B. Pinel-Alloul & M. Gélinas, 2006. On ultimate reasons for summer diapause of Daphnia in a permanent lake. Verhandlungen Internationale Vereinigung für Limnologie 29: 1440–1442.Google Scholar
- Sommer, U., Z. M. Gliwicz, W. Lampert & A. Duncan, 1986. The PEG-model of seasonal succession of planktonic events in fresh waters. Archiv für Hydrobiologie 106: 433–471.Google Scholar
- Tollrian, R. & S. I. Dodson, 1999. Inducible defences in Cladocera: constraints, costs and multipredator environments. In Tollrian, R. & C. D. Harvell (eds), The Ecology and Evolution of Inducible Defenses. Princeton University Press, New Jersey: 177–202.Google Scholar
- Tollrian, R. & C. D. Harvell, 1999. Ecology and evolution of inducible defenses. Princeton University Press, Princeton, NJ.Google Scholar