Data from: Coevolution and the architecture of mutualistic networks

Although coevolution is widely recognized as an important evolutionary
process for pairs of reciprocally specialized species, its importance
within species-rich communities of generalized species has been
questioned. Here we develop and analyze mathematical models of mutualistic
communities, such as those between plants and pollinators or plants and
seed-dispersers to evaluate the importance of coevolutionary selection
within complex communities. Our analyses reveal that coevolutionary
selection can drive significant changes in trait distributions with
important consequences for the network structure of mutualistic
communities. One such consequence is greater connectance caused by an
almost invariable increase in the rate of mutualistic interaction within
the community. Another important consequence is altered patterns of
nestedness. Specifically, interactions mediated by a mechanism of
phenotype matching tend to be anti-nested when coevolutionary selection is
weak and even more strongly anti-nested as increasing coevolutionary
selection favors the emergence of reciprocal specialization. In contrast,
interactions mediated by a mechanism of phenotype differences tend to be
nested when coevolutionary selection is weak, but less nested as
increasing coevolutionary selection favors greater levels of
generalization in both plants and animals. Taken together, our results
show that coevolutionary selection can be an important force within
mutualistic communities, driving changes in trait distributions,
interaction rates, and even network structure.