Data from: Ant mutualism increases long-term growth and survival of a common Amazonian tree

How ecological context shapes mutualistic relationships remains poorly
understood. We combined long-term tree census data with ant censuses in a
permanent 25-ha Amazonian forest dynamics plot to evaluate the effect of
the mutualistic ant Myrmelachista schumanni (Formicinae) on the growth and
survival of the common Amazonian tree Duroia hirsuta (Rubiaceae),
considering its interactions with tree growth, population structure, and
habitat. We found that the mutualist ant more than doubled tree relative
growth rates and increased odds of survival. However, host tree size and
density of conspecific neighbors modified the effect of the ant. Smaller
trees hosting the mutualist ant consistently grew faster when surrounded
by higher densities of conspecifics, suggesting that the benefit to the
tree outweighs any negative effects of high conspecific densities.
Moreover, our findings suggest that the benefit afforded by the ant
diminishes with plant age and also depends on the density of conspecific
neighbors. We provide the first long-term large-scale evidence of how
mutualism affects the population biology of an Amazonian tree species.