antplant

Antplants, or myrmecophytes, are plants that form mutualistic associations with ants. In these relationships the plant provides nesting space and often food resources, while the ants defend the plant against herbivores, pests, and competing vegetation. Antplants occur in tropical forests around the world and include a variety of growth forms, from trees and shrubs to epiphytes.

Most antplants have specialized structures to house ant colonies. Domatia are hollow thorns, leaf pouches, or stems that offer nesting cavities. Plants may also possess extrafloral nectaries that secrete sugary nectar to feed visiting ants, and Beltian bodies or similar lipid-rich structures on leaflets as food for ant workers. Some epiphytic species, such as Hydnophytum and Myrmecodia, develop enlarged tubers that serve as “ant houses” containing colonies within their tissues.

Ecologically, the mutualism ranges from facultative to obligate. Ants provide protection from herbivores, prune competing vegetation, and sometimes clear away seeds or inflorescences that attract herbivores. In return, plants invest energy to produce domatia and food rewards. The specificity and outcome of the interaction can vary among species and environments.

Notable examples include Cecropia trees in the Neotropics, which host Azteca ants; Acacia cornigera, a classic East-Pacific example with Pseudomyrmex ferruginea; and various tuberous ant-plants in the Indo-Pacific such as Hydnophytum and Myrmecodia. Antplants illustrate coevolutionary strategies that link plant anatomy with insect behavior.