Abstracts (first author)
Perceived predation risk accelerates aging in water fleas
Exposure to chemical cues of fish triggers adaptive response in water flea life history, leading to increased early reproduction. This has a cost, as lifespan in the environment free of such cues of predation is 20% longer. The aim of this study was to establish the biodemographic basis of phenotypic differences in water flea lifespan that are induced by the cues of fish predation, and to test for the change in the rate of aging, in particular. We examined mortality using large heterogeneous cohorts of two cladoceran species, Daphnia longispina and Diaphanosoma brachyurum, and found that the exposure to these chemical cues increase the Gompertzian rate of mortality acceleration. The phenotypic response is comparable to previously shown genetically based differences between Daphnia from habitats of different predation risk. The cue of extrinsic mortality risk from fish predation – a key factor shaping cladoceran life histories in the wild – is one of the few interventions shown so far to induce a plastic change in the rate of aging.