Kwinana Rockingham Mandurah Branch 20 March 2023

Eleven members attended this meeting to hear the speaker, KRMB member, Daniel Heald, deliver a slide presentation entitled Ant-Plant Relationships, Myrmecophytes, Myrmechochory, Mutualisms and Modifications. While many see ants as pests, Daniel explained that many plant species had developed beneficial relationships with ants.

Myrmecophytes, otherwise known as ant plants, share a mutualistic relationship with a colony of ants. These relationships can take many forms. For example, Bioturbation, or soil disturbance, sees ant colonies, such as Pogonomyrmex badius, the Florid Harvester Ant, excavating deep nests, where they store the seeds of grasses in the many subterranean tunnels. Pollination by ants is quite rare, with less than 50 confirmed mutualisms. Two examples are found locally: Smoke Bush Conospermum undulatum and the Hare Orchid (Leporella fimbriata) pollinated by male-winged Bull Ants.

Myrmecochory is the dispersal of seeds by ants. It is found in at least 11,000 species of plants, with 1,500 species in Australia and 1,000 in the Fynbos (South African heathland). Common to all such plants is the production of elaiosomes or “food bodies”, structures attached to the seeds rich in lipids, amino acids or other nutrients attractive to ants. This helps with soil fertility and is good for seed germination. Some ant species live in an Arboreal Habitat, some using the canopy for nesting and frequent foraging at branch tips. An example is the Green Tree Ant of the tropics. In African Savannah habitats, certain species of Acacia produce structures called Beltian Bodies on the tip that secrete oils and proteins as food for ants. Muellerian bodies are lipid-rich food bodies found on young leaves of the genus Maranga and glycogen food bodies found on the petioles of Cecropia trees.

An unusual mutualism occurs with the Pitcher Plant Nepenthes bicalarata (found in NW Borneo). Ants of Camponotus schmitzi can swim in the liquid within the pitcher and remain submerged for up to 30 seconds. The ant targets large prey items that, if left in the liquid, would poison the plant. The pitcher plant also gets nutritional benefits from the egested waste the ants produce.

Daniel finished his presentation with a discussion of Ant Gardens, a mutualistic interaction between certain species of arboreal ants and various epiphytic plants. It is a structure made in the tree canopy by the ants that is filled with debris and other organic matter in which epiphytes grow. The ants benefit from this arrangement by having a stable framework to build their nest, while the plants benefit by obtaining nutrients from the soil and the moisture retained there. It was a very interesting presentation.

Colin Prickett