The third characteristic of the co-evolutionary process is the temporal dynamics of traits involved in the interaction. In mutual dependence one prediction is that these dynamics are reduced since change hinders efficient
interaction between the species, leading to stabilizing selection. A possible illustration is in the mutualisms that involve ancient asexuals; they include some mycorrhizal fungi,which inhabit the roots of plants, and the fungi that are the food for leaf-cutter ants (Chapter 2). Another type of interaction that can stabilize traits involves competitive interactions between plant species that occur in co-evolutionary successional cycles. In these, succession creates patterns of association between species in which co-evolution occurs. This is best documented from white clover in grassland ecosystems. The clover becomes adapted to flourish best next to whatever species of grass it has become associated with. This is a particular kind of local adaptation. As a result, competition between the clover and the grass is ameliorated (Turkington 1989). Other interactions involve different trait dynamics. Escape-and-radiation co-evolution involves periods of trait stability and instability. Co-evolutionary arms races imply trait dynamics, although local equilibria may be achieved, and dynamics are also found in co-evolutionary turnover and co-evolutionary alternation. Diversifying co-evolution implies nothing particular about these dynamics.
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