The ecological world of driver ants (Dorylus): a review

Maximillian P. T. G. Tercel , Sebastian Huber, Patricia Rodrigues, Norina Carlos de Jesus Francisco Vicente, Luke L Powell

Driver ants (Dorylus) are among the most conspicuous and abundant predators in continental Africa. Their enormous surface-swarm raids and nomadic lifestyle have captivated naturalists for over 150 years, yet their ecology remains surprisingly poorly understood, especially compared to their Neotropical counterparts. Here, we review the ecology of African driver ants, synthesising knowledge of their taxonomy, evolution, life history, behaviour, trophic ecology, community effects, and ecological associates. Driver ants are formidable generalist predators extracting large quantities of prey from extensive areas. Their raids have long been hypothesised to create pronounced variable disturbances on the forest floor that may have a role in maintaining community structure and beta-diversity. At the same time, their nests and raids support an extraordinary diversity of organisms, including ant-following birds, vertebrate predators, myrmecophilous beetles, flies and other specialised associates. Such interactions suggest that driver ants influence tropical forest communities well beyond the direct and indirect effects of their raids. However, much of what we know of driver ants and their effects on African ecosystems remain based on natural history observations rather than quantitative or experimental evidence. In particular, we still lack a clear understanding of how driver ant raids alter arthropod community composition and diversity, details of their movement ecology, their vulnerability to anthropogenic change, and how strongly other organisms depend on driver ants. We critically evaluate the evidence for considering driver ants as ‘keystone predators’ and highlight the difficulties of applying this concept to nomadic superorganisms whose effects operate across multiple spatiotemporal scales. Finally, we identify emerging approaches that could pave the way to more comprehensively understanding the ecology of driver ants and their influence on African ecosystems. Our review highlights that driver ants are not simply abundant predators, but almost certainly ecologically central components of African rainforest ecosystems whose influence extends across trophic levels, spatial scales and biological communities. Understanding and quantifying these effects in detail is the next step to describing how driver ants fit into the wider ecosystem, and what might be lost in their absence.