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Changes in water chemistry can disable plankton prey defenses.

ABSTRACT: 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.

SUBMITTER: Riessen HP

PROVIDER: S-EPMC3458369 | biostudies-literature | 2012 Sep

REPOSITORIES: biostudies-literature

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Changes in water chemistry can disable plankton prey defenses.

Riessen Howard P HP Linley Robert Dallas RD Altshuler Ianina I Rabus Max M Söllradl Thomas T Clausen-Schaumann Hauke H Laforsch Christian C Yan Norman D ND

Proceedings of the National Academy of Sciences of the United States of America 20120904 38

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 dis ...[more]

PMID: 22949653

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Changes in water chemistry can disable plankton prey defenses.

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Changes in water chemistry can disable plankton prey defenses.

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