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Species coexistence and pathogens with frequency-dependent transmission
Volker H W Rudolf1, Janis Antonovics
1Department of Biology, University of Virginia, Charlottesville, Virginia 22904-4327, USA. vrudolf@virginia.edu
The American Naturalist
|June 7, 2005
Summary
Sharing pathogens with other hosts can prevent extinction, challenging the idea that shared diseases always harm populations. This study reveals how shared pathogens can create apparent mutualism and impact host diversity.
Area of Science:
- Ecology
- Epidemiology
- Evolutionary Biology
Background:
- Pathogens infecting multiple hosts are often transmitted by vectors, with transmission rates influenced by host or vector infection proportions (frequency dependence).
- Shared pathogens are typically assumed to cause apparent competition, negatively impacting host populations.
Purpose of the Study:
- To investigate how sharing a pathogen with an alternative host influences pathogen-mediated extinction in a two-host system.
- To explore the concept of apparent mutualism mediated by shared pathogens.
Main Methods:
- Utilized a mathematical model of a two-host, one-pathogen system.
- Incorporated frequency-dependent transmission dynamics.
- Analyzed the influence of host sharing on pathogen-mediated extinction risk.
Main Results:
- Frequency-dependent transmission can lead to host rescue from pathogen-mediated extinction when a second host shares the pathogen.
- Demonstrated that shared pathogens can mediate apparent mutualism, contradicting the notion of universal apparent competition.
- Identified two distinct types of dilution effects based on transmission and host density.
Conclusions:
- Shared pathogens do not always lead to apparent competition; they can facilitate apparent mutualism.
- Host sharing and pathogen transmission dynamics significantly influence host population persistence and species interactions.
- Understanding these dynamics is crucial for comprehending the role of pathogens in maintaining host diversity.