Ant–caterpillar antagonism at the community level: interhabitat variation of tritrophic interactions in a neotropical savanna

1. Ant foraging on foliage can substantially affect how phytophagous insects use host plants and represents a high predation risk for caterpillars, which are important folivores. Ant–plant–herbivore interactions are especially pervasive in cerrado savanna due to continuous ant visitation to liquid food sources on foliage (extrafloral nectaries, insect honeydew). While searching for liquid rewards on plants, aggressive ants frequently attack or kill insect herbivores, decreasing their numbers.
Because ants vary in diet and aggressiveness, their effect on herbivores also varies. Additionally, the differential occurrence of ant attractants (plant and insect exudates) on foliage produces variable levels of ant foraging within local floras and among localities. Here, we investigate how variation of ant communities and of traits among host plant species (presence or absence of ant attractants) can change the effect of carnivores (predatory ants) on herbivore communities (caterpillars) in a c...