In relationships based on mutuality, the number of
individuals involved can determine the rate at which species evolve
The relationship between species determines how rapidly they
evolve. Parasites and their hosts coevolve more rapidly, and partners in a
mutualistic relationship can evolve more slowly. But this view is obviously too
simplistic. The rate of evolution in a mutualistic relationship does not depend
only on the type of interactions, but also on the number of individuals
involved, according to a model developed by researchers.