Human disturbance promotes herbivory by leaf-cutting ants in the Caatinga dry forest

Anthropogenic disturbances are known to modify plant-animal interactions such as those involving the leaf-cutting ants, the most voracious and proliferating herbivore across human-modified landscapes in the Neotropics. Here we evaluate the effect of chronic anthropogenic disturbance (e.g. firewood collection, livestock grazing) and vegetation seasonality on foraging area, foliage availability in the foraging area, leaf consumption, and herbivory rate of the leaf-cutting ant Atta opaciceps in the semi-arid Caatinga, a mosaic of dry forest and scrub vegetation in northeast Brazil. Contrary to our initial expectation, the foraging area was not affected by either disturbance intensity or the interaction between season and disturbance intensity. However, leaf consumption and herbivory rate were higher in more disturbed areas. We also found a strong effect of seasonality, with higher leaf consumption and herbivory rate in the dry season. Our results suggest that the foraging ecology of leaf-c...