myrmecophytes

Myrmecophytes are plants that establish close, mutualistic relationships with ants. In these interactions, the plant provides nesting space, food, or both, while the ants defend the plant from herbivores and competing vegetation, and sometimes aid in nutrient acquisition or seed dispersal. The associations are often highly specialized and have evolved repeatedly in tropical ecosystems.

Many myrmecophytes possess specialized structures that house ant colonies (domatia). These include hollow stems, swollen thorns, leaf pouches, and large tuberous roots or caudices. In addition to shelter, plants may offer food resources such as nectar from extrafloral nectaries or lipid- and protein-rich food bodies attached to leaves or surfaces. Some species also produce nectar or secretions that specifically reward the ants for guarding the plant.

Well-known myrmecophytic lineages include Myrmecodia and Hydnophytum (ant plants with tuberous, chambered roots) in the Pacific, as well as tropical American examples such as Tococa, Hirtella, Cordia nodosa, and Cecropia, which host diverse ant partners. Acacia species in Africa and the New World are famous for swollen thorns housing ants, complemented by nectar and defense against herbivores. In some Amazonian systems, plants such as Duroia hirsuta and Hirtella physophora interact with aggressive ant species like Myrmelachista or Allomerus to suppress plant competitors and herbivores.

Myrmecophyte relationships are not universal; many plants attract ants facultatively without specialized domatia, and not all ant-plant interactions are mutualistic. When mutualisms are obligate, both partners rely on the association for survival in their habitat.