The impact of natural and anthropogenic conditions on physiology and stoichiometry in damselflies

There is increasing awareness that predators not only affect prey through direct consumption, but also without consuming them through 'fear' effects. These fear effects, which may even be stronger than direct consumption, operate through physiological stress in the prey. While the general stress response is well-documented in vertebrates, the underlying mechanisms and consequences remain poorly known in invertebrates. By using the damselfly Enallagma cyathigerum as a model system, I will first study the different components (physiological/biochemical) of the predator-induced stress response during shortterm and long-term predation risk. This way I can generate for the first time a unique integrated picture within a single species. Moreover, I will link the stress response to typical antipredator behaviours. Secondly, based on recent evidence in a terrestrial ecosystem, I will investigate the effects of fear on the elemental composition of the prey and how this translates into changes in a key ecosystem function, detritus composition rate. Thirdly, I will test for general patterns in the differences in the stress response among individuals and species. At the individual level, I will study if the predator-induced stress response predictably differs between bold and shy individuals. At the species level, I will test for covariation in the predator-induced stress response between damselflies species with a different behavioural and life-history response to predation risk.status: publishe