PARENT SESSION
Contributed Oral Session 161: Predator - Prey Ecology: Aquatic Habitat and Food Webs
Friday, August 12, 8:00 AM - 11:30 AM, Meeting Room 519 B, Level 5, Palais des congrès de Montréal
The mechanics of risk: the relevance of pysiology and feeding to life histories under predation risk.
Beckerman, Andrew*,1, Wieski, Kazimierz2, Baird, Donald3, 1 Department of Animal and Plant Sciences, Sheffield, UK2 Department of Fish Biology, Szczecin, Poland3 NWRI/Environment Canada - Canadian Rivers Institute, Fredcricton, New Brunswick, Canada
ABSTRACT- Predation is one the most evocative of interactions among species and is important to our understanding of the function of natural and anthropogenically modified systems. Recent research on a wide variety of taxa has shown that predators not only consume their prey, but as a consequence, also frighten them, causing changes in morphology, behaviour and life history that have survival benefits, but also costs. While there are many examples of feeding rate change and habitat shifts among prey organisms, few studies have explored how organisms balance energy supply and demand in the face of predation risk, thus shaping life-history patterns. To this end, we examined Daphnia magna energy expenditure (respiration) and energy intake (feeding), over the duration of their life cycle, in the face of predation risk from sticklebacks (Gasterosteus aculeatus). Combined with parallel investigation of the life history under predation risk, our data show that chemical cues from fish increase energy expenditure and reduce food intake leading to reduced net energy intake. This consequence of physiological and behavioural changes in D. magna are accompanied by established patterns of reduced size and age at maturity in the face of vertebrate predation. This suggests that the energy budget plays an integrating role in how life histories reflect levels of predation risk.
Key words: Daphnia magna, predation risk, respiration, foraging