Abstract
Persistence is a central issue in population ecology with important implications for population management. Most theoretical studies have focused on continually interacting populations, even though many systems are subject to ecological disturbances which confound analysis of persistence. In this paper, we use a combination of a simple parasite–hyperparasite model with disturbances and field data to investigate the factors contributing to the observed persistence of the parasite population. The field data are taken from a two-year experiment (including five growing seasons) investigating the use of the mycoparasite Sporidesmium sclerotivorum as a persistent biological control agent of Sclerotinia minor, an economically important fungal parasite of lettuce. We show that the standard assumption of homogeneous mixing fails to predict the observed persistence of the parasite population. We demonstrate that allowing for heterogeneous mixing prevents the fade-out predicted in the homogeneous mixing case. The implications of the results for broad classes of host–parasite systems are discussed.
Keywords: Epidemiology Models Biological Control Parameter Estimation Sclerotina Minor Sporidesmium Sclerotivum
Full Text
The Full Text of this article is available as a PDF (314.8 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Allen J. C., Schaffer W. M., Rosko D. Chaos reduces species extinction by amplifying local population noise. Nature. 1993 Jul 15;364(6434):229–232. doi: 10.1038/364229a0. [DOI] [PubMed] [Google Scholar]
- Anderson R. M., May R. M. The invasion, persistence and spread of infectious diseases within animal and plant communities. Philos Trans R Soc Lond B Biol Sci. 1986 Dec 15;314(1167):533–570. doi: 10.1098/rstb.1986.0072. [DOI] [PubMed] [Google Scholar]
- Bolker B. M., Grenfell B. T. Chaos and biological complexity in measles dynamics. Proc Biol Sci. 1993 Jan 22;251(1330):75–81. doi: 10.1098/rspb.1993.0011. [DOI] [PubMed] [Google Scholar]
- Bolker B., Grenfell B. Space, persistence and dynamics of measles epidemics. Philos Trans R Soc Lond B Biol Sci. 1995 May 30;348(1325):309–320. doi: 10.1098/rstb.1995.0070. [DOI] [PubMed] [Google Scholar]
- Carroll J. E., Lamberson R. H., Roe S. Sinks, sources, and spotted owls: a territorial population model with continuous mortality and discrete birth. Math Biosci. 1995 Oct;129(2):169–188. doi: 10.1016/0025-5564(94)00059-9. [DOI] [PubMed] [Google Scholar]
- Hanski I., Turchin P., Korpimäki E., Henttonen H. Population oscillations of boreal rodents: regulation by mustelid predators leads to chaos. Nature. 1993 Jul 15;364(6434):232–235. doi: 10.1038/364232a0. [DOI] [PubMed] [Google Scholar]
- Knell R. J., Begon M., Thompson D. J. Transmission dynamics of Bacillus thuringiensis infecting Plodia interpunctella: a test of the mass action assumption with an insect pathogen. Proc Biol Sci. 1996 Jan 22;263(1366):75–81. doi: 10.1098/rspb.1996.0013. [DOI] [PubMed] [Google Scholar]
- Liu W. M., Hethcote H. W., Levin S. A. Dynamical behavior of epidemiological models with nonlinear incidence rates. J Math Biol. 1987;25(4):359–380. doi: 10.1007/BF00277162. [DOI] [PubMed] [Google Scholar]
- London W. P., Yorke J. A. Recurrent outbreaks of measles, chickenpox and mumps. I. Seasonal variation in contact rates. Am J Epidemiol. 1973 Dec;98(6):453–468. doi: 10.1093/oxfordjournals.aje.a121575. [DOI] [PubMed] [Google Scholar]
- Pacala S. W., Hassell M. P., May R. M. Host-parasitoid associations in patchy environments. Nature. 1990 Mar 8;344(6262):150–153. doi: 10.1038/344150a0. [DOI] [PubMed] [Google Scholar]