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Population dynamics under parasitic sex ratio distortion
M J Hatcher1, D E Taneyhill, A M Dunn
1School of Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom.
Theoretical Population Biology
|August 10, 1999
Summary
Feminizing parasites can drive host populations toward extinction by severely distorting the sex ratio. However, parasite elimination in small populations may allow host recovery, making infections transient.
Area of Science:
- Population dynamics
- Parasitology
- Evolutionary biology
Background:
- Vertically transmitted parasites can distort host sex ratios.
- Feminizing parasites pose a significant threat to host population stability.
Purpose of the Study:
- To analyze the population dynamic effects of sex ratio distortion caused by feminizing parasites.
- To investigate the conditions under which these parasites lead to host extinction or population regulation.
Main Methods:
- Mathematical modeling of host-parasite population dynamics.
- Analysis of Allee effects and density dependence.
- Consideration of stochastic parasite elimination in finite populations.
Main Results:
- Sex ratio distortion by feminizing parasites can lead to host population extinction due to a lack of males for reproduction.
- Feminizers can exacerbate Allee effects, increasing extinction risk for small populations.
- Parasite prevalence and host equilibrium density are influenced by mating constraints and density dependence.
- Stochastic parasite elimination can enable host population recovery even under deterministic extinction conditions.
Conclusions:
- Infection by parasitic sex ratio distorters can be transient in finite host populations.
- Understanding these dynamics is crucial for parasite prevalence, host population regulation, and sex ratio evolution.