Evolutionary suicide in spatial host-pathogen systems
A population of pathogens that search for a host in space, infect it and then kill it, cannot persist if the pathogen has a too mild or a too aggressive strategy. In the first case, the pathogens would quickly die because of the low chances it has to infect an healthy host; in the latter, it would rapidly burn out all infectable hosts. My project is to understand what happens when one or more traits of the pathogen is allowed to mutate. It is possible that evolution of the pathogens will lead the population to hover just below a critical value of transmissibility; but it is also possible that evolution will take it all the way to extinction. The former could happen in spatially extended host-pathogen populations through cluster-level selection: pathogens that transmit too efficiently remove themselves from the pathogens by eradicating their host clusters.