Suppression of savanna ants alters invertebrate composition and influences key ecosystem processes

In almost every ecosystem, ants( Hymenoptera: Formicidae) are the dominant terrestrial invertebrategroup. Their functional value was highlighted by Wilson (1987) who famously declared that invertebratesare the “little things that run the world.” However, while it is generally accepted that antsfulfil important functions, few studies have tested these assumptions and demonstrated what happens in their absence. We report on a novel large-scale field experiment in undisturbed savanna habitat where we examined how antsinfluence the abundance of other invertebratetaxa in the system, and affect the key processes of decomposition and herbivory. Our experiment demonstrated that antssuppressed the abundance and activity of beetles, millipedes, and termites, and also influenced decomposition rates and levels of herbivory. Our study is the first to show that top-down control of termites by antscan have important ecosystem consequences. Further studies are needed to elucidate the effects antcommunities have on other aspects of the ecosystem (e.g., soils, nutrient cycling, the microbial community) and how their relative importance for ecosystem function varies among ecosystem types (e.g., savanna vs. forest).