Conclusion
Despite considerable phylogenetic uncertainty in the data, we found an
influence of ecotone on the rates and timing of diet transitions for
sigmodontine rodents. This result is especially noteworthy as there may
be only subtle differences in the rates of transition and time of diet
evolution between ecotone and core species, owing to lagged responses to
environmental changes. The spatial analysis of diet evolution shed light
on the evolutionary pathways that sigmodontine rodents tracked to
achieve such an impressive diversity, and expand and survive into the
large range of habitats in which they occur today.
Our approach provides a formal
link between macroecology and macroevolution, and can be incorporated in
more sophisticated approaches integrating reconstruction of ancestral
areas and ecological traits.