Template:EvoLudo/Recent

Mutualisms: cooperation between species

Upcoming: new tutorial on inter-species interactions in preparation. Cooperative interactions between species are the foundation of all mutualistic associations. Compared to within species interactions, the problem of cooperation is exacerbated because cooperation bestows benefits to members of another species. Mutual benefits require inter-species coordination to prevent exploitation. Here we show that in the spatial prisoner's dilemma surprisingly rich dynamics emerge with distinct dynamical domains separated by critical phase transitions, which imply arbitrarily large fluctuations and diverging spatial correlations. Most importantly, cooperative behaviour not only persists, but may result in intriguing, spontaneous symmetry breaking in the level of cooperation in each species. Evolution may favour asymmetric states that effectively separate species into cooperative producers and defecting consumers. Surprisingly, the asymmetry becomes more pronounced under more benign conditions of cooperation.

1. Hauert, C., & Szabó, G. (2024) PNAS Nexus (in print).

Evolutionary graph theory

New tutorial added on evolutionary graph theory, which provides a formal approach to describe the spreading and fixation (or extinction) of a mutant type in structured populations. Interestingly, the fixation probabilities remain unaffected by the underlying structure for a large class of graphs. However, some graphs may act either as amplifiers or suppressors of selection by increasing or decreasing the fixation probabilities as compared to unstructured populations. In contrast, fixation and absorption times are very sensitive to changes in the graph structure and hence vary greatly even for graphs that leave fixation probabilities unchanged. Even though fixation times are, in general, not preserved between graphs, symmetries of a graph can at least ensure that fixation times do not depend on the initial location of the mutant. This summarizes research efforts that span over a decade, including:

1. McAvoy, A. & Hauert, C. (2015) J. R. Soc. Interface 12 20150420 doi: 10.1098/rsif.2015.0420
2. Jamieson-Lane, A. & Hauert, C. (2015) J. Theor. Biol. 382 44-56 doi: 10.1016/j.jtbi.2015.06.029
3. Lieberman, E., Hauert, C. & Nowak, M. (2005) Nature 433 312-316 doi: 10.1038/nature03204.