TY - JOUR A1 - Riessen, Howard P. A1 - Linley, Robert Dallas A1 - Altshuler, Ianina A1 - Rabus, Max A1 - Söllradl, Thomas A1 - Clausen-Schaumann, Hauke A1 - Laforsch, Christian A1 - Yan, Norman D. T1 - Changes in water chemistry can disable plankton prey defenses T2 - PNAS N2 - The effectiveness of antipredator defenses is greatly influenced by the environment in which an organism lives. In aquatic ecosystems, the chemical composition of the water itself may play an important role in the outcome of predator–prey interactions by altering the ability of prey to detect predators or to implement defensive responses once the predator’s presence is perceived. Here, we demonstrate that low calcium concentrations (<1.5 mg/L) that are found in many softwater lakes and ponds disable the ability of the water flea, Daphnia pulex to respond effectively to its predator, larvae of the phantom midge, Chaoborus americanus. This low-calcium environment prevents development of the prey’s normal array of induced defenses, which include an increase in body size, formation of neck spines, and strengthening of the carapace. We estimate that this inability to access these otherwise effective defenses results in a 50–186% increase in the vulnerability of the smaller juvenile instars of Daphnia, the stages most susceptible to Chaoborus predation. Such a change likely contributes to the observed lack of success of daphniids in most low-calcium freshwater environments, and will speed the loss of these important zooplankton in lakes where calcium levels are in decline. KW - Plankton KW - Hydrochemie Y1 - 2022 UR - https://opus4.kobv.de/opus4-hm/frontdoor/index/index/docId/275 UR - https://nbn-resolving.org/urn:nbn:de:bvb:m347-opus-2757 N1 - Sonderdruck aus: PNAS vol. 109, no. 38, 15377–15382 https://doi.org/10.1073/pnas.1209938109 VL - 109 IS - 38 SP - 15377 EP - 15382 ER -