The Red King Effect: When the slowest runner wins the coevolutionary race

Mutualisms provide benefits to those who participate in them. As a mutualism evolves, how will these benefits come to be allocated among the participants? We approach this question using evolutionary game theory and explore the ways in which the coevolutionary process determines the allocation of benefits in a mutualistic interaction. Motivated by the Red Queen theory, which states that coevolutionary processes favor rapid rates of evolution, we pay particular attention to the role of evolutionary rates in the establishment of mutualism and the partitioning of benefits among mutualist partners. We find that, contrary to the Red Queen, in mutualism evolution the slowly evolving species is likely to gain a disproportionate share of the benefits. Moreover, population structure serves to magnify the advantage to the slower species. Our results highlight the complexity of the coevolutionary process and the often counterintuitive consequences to which it gives rise.