title: Environmental fluctuations restrict eco-evolutionary dynamics in predator-prey system.
abstract: Environmental fluctuations, species interactions and rapid evolution are all predicted to affect community structure and their temporal dynamics. Although the effects of the abiotic environment and prey evolution on ecological community dynamics have been studied separately, these factors can also have interactive effects. Here we used bacteria-ciliate microcosm experiments to test for eco-evolutionary dynamics in fluctuating environments. Specifically, we followed population dynamics and a prey defence trait over time when populations were exposed to regular changes of bottom-up or top-down stressors, or combinations of these. We found that the rate of evolution of a defence trait was significantly lower in fluctuating compared with stable environments, and that the defence trait evolved to lower levels when two environmental stressors changed recurrently. The latter suggests that top-down and bottom-up changes can have additive effects constraining evolutionary response within populations. The differences in evolutionary trajectories are explained by fluctuations in population sizes of the prey and the predator, which continuously alter the supply of mutations in the prey and strength of selection through predation. Thus, it may be necessary to adopt an eco-evolutionary perspective on studies concerning the evolution of traits mediating species interactions.
authors.affiliation: Division of Microbiology and Biotechnology, Department of Food and Environmental Sciences, University of Helsinki, PO Box 65, Helsinki 00014, Finland teppo.hiltunen@helsinki.fi.
authors.forename: Teppo
authors.initials: T
authors.lastname: Hiltunen
authors.affiliation: Department of Evolutionary Ecology, Community Dynamics Group, Max Planck Institute for Evolutionary Biology, August Thienemann Street 2, Plön 24306, Germany.
authors.forename: Gökçe B
authors.initials: GB
authors.lastname: Ayan
authors.affiliation: Department of Evolutionary Ecology, Community Dynamics Group, Max Planck Institute for Evolutionary Biology, August Thienemann Street 2, Plön 24306, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Becks
mesh_terms: D005075:Biological Evolution; D004777:Environment; D020387:Food Chain; D011157:Population Dynamics; D011551:Pseudomonas fluorescens / Q000502:physiology*; D012641:Selection, Genetic; D016808:Tetrahymena thermophila / Q000502:physiology*
keywords: Pseudomonas fluorescens SBW25; Tetrahymena thermophila; coevolution; community dynamics; eco-evolutionary dynamics; temporal fluctuations