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Parasitism effects on coexistence and stability within simple trophic modules
Loïc Prosnier1, Vincent Médoc1, Nicolas Loeuille1
1Sorbonne Université, Université Paris Diderot, Université Paris-Est Créteil, CNRS, INRA, IRD, Institute of Ecology and Environmental Science - Paris (iEES-Paris), Campus Pierre et Marie Curie, 4 place Jussieu, Paris 75005, France.
Journal of Theoretical Biology
|September 10, 2018
Summary
Parasites can surprisingly increase species coexistence in food webs by altering competition dynamics. Their impact on ecosystem stability depends on whether the parasite infects prey or predators.
Area of Science:
- Ecology
- Parasitology
- Theoretical Ecology
Background:
- Parasites are key food web components, but their indirect effects on non-host species are poorly understood.
- Investigating indirect ecological impacts of parasites is crucial for understanding food web dynamics.
Purpose of the Study:
- To investigate how parasitism affects species coexistence and food web stability.
- To analyze the consequences of parasite infection in prey versus predator species.
Main Methods:
- A simple trophic module model (one predator, two competing prey) was used.
- Two parasite effects were modeled: virulence (reduced host growth) and interaction (altered host behavior/consumption).
- Mathematical modeling explored population dynamics under different infection scenarios.
Main Results:
- Parasitism favors prey coexistence when parasite effects are of intermediate intensity, by modifying direct and apparent competition.
- Prey infection can reduce coexistence due to predator-parasite competition.
- Predator infection stabilizes the food web by increasing energy transfer and/or predator mortality.
Conclusions:
- Parasites can potentially enhance species coexistence and alter food web stability.
- The specific effects of parasites (virulence, interaction) and the infected species determine the overall ecological outcome.
- Further research is needed to precisely predict parasite impacts on trophic networks.
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