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Parasites alter community structure.
Chelsea L Wood1, James E Byers, Kathryn L Cottingham
1Department of Biological Sciences, Dartmouth College, 103 Gilman Hall, Hanover, NH 03755, USA.
Summary
Parasites like Cryptocotyle lingua reduce the grazing by snails Littorina littorea, altering macroalgal communities. This parasite-induced snail behavior impacts intertidal ecosystems and their food webs.
Area of Science:
- Marine ecology
- Parasitology
- Community ecology
Background:
- Parasites can alter host behavior and physiology, influencing ecological interactions.
- The snail Littorina littorea is a dominant herbivore in North Atlantic rocky intertidal zones.
- Littorina littorea is frequently infected by the digenean trematode parasite Cryptocotyle lingua.
Purpose of the Study:
- To investigate how Cryptocotyle lingua infection affects Littorina littorea grazing behavior.
- To determine if altered snail grazing impacts macroalgal community composition.
- To understand the indirect effects of parasites on intertidal community structure.
Main Methods:
- Laboratory experiments measuring macroalgal consumption by infected and uninfected snails.
- Field observations assessing macroalgal cover in areas with differing snail grazing pressure.
- Analysis of trait-mediated indirect effects of parasitism on host behavior.
Main Results:
- Uninfected snails consumed 40% more macroalgal biomass than infected snails in laboratory settings.
- Infected snails exhibited reduced grazing rates, leading to increased macroalgal cover in field experiments.
- Parasitism significantly altered the grazing behavior of the dominant herbivore, Littorina littorea.
Conclusions:
- Cryptocotyle lingua infection reduces Littorina littorea grazing, indirectly promoting macroalgal growth.
- Parasites can be significant drivers of ecological community structure through trait-mediated indirect effects.
- Understanding host-parasite interactions is crucial for predicting changes in marine ecosystems.
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