Ants (Hymenoptera: Formicidae) can be extremely abundant in forest canopies and can constitute more than half the individual organisms and half the arthropod biomass of tropical forest canopy samples. Compared to other arthropod groups (e.g., beetles, spiders) this abundance of tropical canopy ants is comprised of relatively few species. Here we use a global database of ant diversity and abundance to quantify spatial patterns of canopy ant diversity and abundance and to model the relationships between these patterns and the distribution of climate. We compare the empirical patterns of diversity and the model generated for canopy ants with those of ground-dwelling ants, testing the simple hypothesis that canopy diversity mirrors ground ant diversity. We also test the prediction that the seasonality of precipitation and temperature are more important in delimiting patterns of abundance and diversity of canopy ants. In addition, we consider the timing of the origin of canopy ant clades (relative to clades of ground-dwelling ants) and the consequences of shifts to the canopy for the rate of diversification of canopy ants.
Results/Conclusions
Generally, patterns of abundance and diversity of canopy ants differ from those of ground dwelling ants Ground dwelling ant diversity is (at a global spatial extent) positively correlated with temperature and weakly negatively correlated with precipitation. In contrast, canopy ants are most diverse in warm, wet and relatively aseasonal environments. Canopy ant diversity is more strongly influenced by precipitation and by the seasonality of both precipitation and temperature than are ground-foraging ants. The importance of climatic seasonality, which is likely correlated with resource availability and access, argues that seasonal resource limitation may influence canopy ants more strongly than ground ants.
