We use a combination of mathematical analysis and computer simulation to examine the evolution and co-evolution of hosts and parasites. Themes include:
The evolution of host defence: resistance and tolerance
A large body of theoretical work (link) has been developed to look at how ecological feedbacks affect the evolution of defence to parasites. The approach is modern evolutionary game theory that allows the ecological dynamics of the interaction to be taken into account in the evolutionary process. This is of crucial importance in the evolution of defence, since the host strategy will affect the parasite prevalence. For example resistance as it spreads from rare will tend to reduce prevalence and be less advantageous. Other defence mechanisms such as mortality tolerance will have different effects on prevalence.
An early paper is:
Boots, M. & Y. Haraguchi (1999). The evolution of costly resistance in host-parasite systems. The American Naturalist, 153, 359-370.
A key more recent paper is:
Best, A., A. White & M. Boots (2008). The maintenance of host variation in tolerance to pathogens and parasites. Proceedings of the National Academy of Sciences, 105, 20786-20791.
Spatial structure and the evolution of hosts and parasites
There is always some form of spatial or social structure within populations: individuals interact with some individuals more often than others. We use a combination of computer simulation and pair approximation to examine the implication of local interactions to the evolution of parasites. The key to this work is that we examine mixing patterns between the completely local and the completely mixed.
The first paper on this is:
Boots, M. & A. Sasaki (1999). “Small Worlds” and the evolution of virulence: infection occurs locally and at a distance. Proceedings of the Royal Society, Series B, 266,1933-1938,
This has been followed up with a series of theoretical models (link) and now an empirical test of the theory:
Boots, M. and M. Mealor (2007). Local interactions select for lower infectivity. Science, 315, 1184-1186.
The generation of diversity in hosts and parasites
Understanding the drivers of host and parasite diversity is a key challenge in the lab.
Boots M, A.White, A. Best & R. Bowers (2014). How specificity and epidemiology drive the coevolution of static trait diversity in hosts and parasites. Evolution, 68, 1594-1606.
Boots M, A. White, A. Best & R. Bowers (2012). Diversity in host resistance: The importance of who infects whom. Ecology Letters 15, 1104-1111.
How important is coevolution as opposed to evolution to the outcome?
Best, A., A. White & M. Boots (2009). The implications of co-evolutionary dynamics to host-parasite interactions. The American Naturalist 173, 779-791.
Best A, A. White & M. Boots (2014). The co-evolutionary implications of host tolerance. Evolution, 68, 1426-1435.
Ashby B & M. Boots (2015). The coevolution of parasite virulence and host mating strategies. Proceedings of the National Academy of Sciences 112(43) 13290-13295.
What are the implications of immune priming to the ecological and evolutionary outcomes?
Best A, H. Tidbury, A. White and M. Boots (2013). The evolutionary dynamics of within-generation immune priming in invertebrate hosts. Journal of the Royal Society Interface 10, 20120887.
Tidbury H., A. Best & M. Boots (2012). The Epidemiological Consequences of Immune Priming. Proceedings of the Royal Society, B. 279, 4505-4512.
The elephant in the room for many modeling studies is that the outcomes depend critically on the shape of the trade-off curve that is assumed. We have developed a new method (Trade-off invasion plots TIPs) that allows the role of the trade-off shape to be studied explicitly.
Hoyle, A., R.G. Bowers, A. White & M. Boots (2008). The evolutionary implications of the shape of trade-offs in different ecological contexts. Journal of Theoretical Biology. 250, 498-511.
Bowers, R.G., A, Hoyle, M. Boots & A White (2005). The geometric theory of adaptive evolution: Trade-off and invasion plots. Journal of Theoretical Biology. 233, 363-377.
Boots, M & R.G. Bowers (2004). The evolution of acquired immunity. Proceedings of the Royal Society, 271, 715-723.
General ecological theory concentrates on the ecological role of spatial structure in host parasite interactions.
Boots, M. & A. Sasaki. (2002). Extinctions in spatially structured host-pathogen populations. The American Naturalist. 159, 706-713.
We have also addressed generally the issue of disease dynamics under density and frequency dependence.
Ryder, J.J., M Miller, A White, R. J. Knell & M Boots (2007). Disease dynamics under combined frequency- and density-dependent transmission. Oikos 116, 2017-2026.
And Developed resonance approaches to understand disease dynamics.
Greenman, J, M. Kamo & M. Boots (2004). External Forcing of Ecological and Epidemiological Systems: a resonance approach. Physica D, 190, 136-151.