Abstract
The existence of adaptive host manipulation by parasites has received increasing empirical support in recent years. Here I develop an optimality model of the extent of host manipulation, incorporating within-host group size, relatedness and a range of realistic cost–benefit functions. The model highlights the cooperative nature of host manipulation, and the potential for cheating this entails. When relatedness in parasite groups is minimal, manipulation is suppressed, but not eradicated, reflecting the importance of interhost selection. A distinctive threshold phenomenon is predicted for a wide range of parameter values. Below the group size threshold, manipulation is zero. Above the threshold, the predicted behaviour depends critically on the biological details of the individual–group interaction. The host-manipulation model is discussed in the light of two potential applications. If parasite group size is assumed to be a static characteristic of a parasite species or strain, the model generates a set of comparative predictions best suited to macroparasite systems. Additionally, the model can be used to predict density-dependent behavioural changes in expanding groups of parasites, as seen in quorum-sensing bacteria.
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- Bainton N. J., Stead P., Chhabra S. R., Bycroft B. W., Salmond G. P., Stewart G. S., Williams P. N-(3-oxohexanoyl)-L-homoserine lactone regulates carbapenem antibiotic production in Erwinia carotovora. Biochem J. 1992 Dec 15;288(Pt 3):997–1004. doi: 10.1042/bj2880997. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Frank S. A. Models of parasite virulence. Q Rev Biol. 1996 Mar;71(1):37–78. doi: 10.1086/419267. [DOI] [PubMed] [Google Scholar]
- Fuqua C., Winans S. C., Greenberg E. P. Census and consensus in bacterial ecosystems: the LuxR-LuxI family of quorum-sensing transcriptional regulators. Annu Rev Microbiol. 1996;50:727–751. doi: 10.1146/annurev.micro.50.1.727. [DOI] [PubMed] [Google Scholar]
- Grenfell B. T., Wilson K., Isham V. S., Boyd H. E., Dietz K. Modelling patterns of parasite aggregation in natural populations: trichostrongylid nematode-ruminant interactions as a case study. Parasitology. 1995;111 (Suppl):S135–S151. doi: 10.1017/s0031182000075867. [DOI] [PubMed] [Google Scholar]
- Jones S., Yu B., Bainton N. J., Birdsall M., Bycroft B. W., Chhabra S. R., Cox A. J., Golby P., Reeves P. J., Stephens S. The lux autoinducer regulates the production of exoenzyme virulence determinants in Erwinia carotovora and Pseudomonas aeruginosa. EMBO J. 1993 Jun;12(6):2477–2482. doi: 10.1002/j.1460-2075.1993.tb05902.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Poulin R. The evolution of parasite manipulation of host behaviour: a theoretical analysis. Parasitology. 1994;109 (Suppl):S109–S118. doi: 10.1017/s0031182000085127. [DOI] [PubMed] [Google Scholar]
- Poulin R., Thomas F. Phenotypic variability induced by parasites:. Parasitol Today. 1999 Jan;15(1):28–32. doi: 10.1016/s0169-4758(98)01357-x. [DOI] [PubMed] [Google Scholar]
- Robson N. D., Cox A. R., McGowan S. J., Bycroft B. W., Salmond G. P. Bacterial N-acyl-homoserine-lactone-dependent signalling and its potential biotechnological applications. Trends Biotechnol. 1997 Nov;15(11):458–464. doi: 10.1016/S0167-7799(97)01102-5. [DOI] [PubMed] [Google Scholar]
- Smithers S. R., Terry R. J. Immunity in schistosomiasis. Ann N Y Acad Sci. 1969 Oct 6;160(2):826–840. doi: 10.1111/j.1749-6632.1969.tb15904.x. [DOI] [PubMed] [Google Scholar]
- Smithers S. R., Terry R. J. Resistance to experimental infection with Schistosoma mansoni in rhesus monkeys induced by the transfer of adult worms. Trans R Soc Trop Med Hyg. 1967;61(4):517–533. doi: 10.1016/0035-9203(67)90102-2. [DOI] [PubMed] [Google Scholar]
- Taylor P. D., Frank S. A. How to make a kin selection model. J Theor Biol. 1996 May 7;180(1):27–37. doi: 10.1006/jtbi.1996.0075. [DOI] [PubMed] [Google Scholar]
- Thomas F, Renaud F, Poulin R. Exploitation of manipulators: 'hitch-hiking' as a parasite transmission strategy. Anim Behav. 1998 Jul;56(1):199–206. doi: 10.1006/anbe.1998.0758. [DOI] [PubMed] [Google Scholar]