All species of Lecanopteris have greatly modified rhizomes that form hollow chambers in which ants nest and raise their broods.
Although it is rare to find Lecanopteris plants with ant-free domatia, the relationship between Lecanopteris and the ants is facultative rather than obligatory. Each partner can survive without the other, though possibly survival and vigour of the plants may be affected in the absence of ants. Although the ants are not dependent on the rhizomes for nesting, they will take advantage of them whenever they are available.
Lecanopteris plants gain nutrients and water from ants. This happens in several ways:
Plants may in some cases receive protection from being eaten by insects or animals. Crematogaster are small, non-stinging ants that could see disturbance as a threat to their nests and attack when disturbed. There is, however, evidence that they do not always perform this service.
Ants probably assist spore dispersal incidentally while they are foraging.
Section through fresh Lecanopteris spinosa rhizome showing hollow chambers. © AC Jermy
Ants have the benefit of a sheltered safe place to nest and rear their larvae. For an ant colony to thrive, cool, dry and dark conditions are needed. The hollow Lecanopteris rhizome forms a domatium (home) that provides these as:
Ants are found in succulent green rhizomes as well as old blackened ones and probably gain water and nutrients from the plant.
It has been reported that in some Lecanopteris species oil droplets produced in the sporangia may be harvested by ants as a source of food.
In studies of 7 Lecanopteris species, over 30 species of ants were recorded as visiting the plants, 5 of which were ‘regulars’. These were:
Within a population of Lecanopteris, or a particular geographic area or habitat, ants tend to associate with specific species. The same species of ant will colonise most Lecanopteris plants in a population throughout the life of the plants. As long as at least a small portion of the plant is living it will be inhabited by ants but totally dead plants are deserted.
Studies of other species of Lecanopteris have shown that the relationship between ants and ferns is a result of ecology not of co-evolution - when a Lecanopteris species is distributed more widely than the ants, another species of ant takes its place. Not surprisingly, the greatest range of ant species was found in the most widespread fern species, Lecanopteris sinuosa. A single ant species will colonise a range of different ant-epiphytes.
Lecanopteris spinosa was not investigated in that study but ants of the genus Crematogaster were found in L. spinosa rhizomes when they were originally collected and were deposited in the Museum's Entomology collections.
The process by which water and nutrients are absorbed and conveyed to the plant tissues and organs.
Part of a plant that has been modified to provide protection for insects, mites or fungi.
Plants that grow on another plant for support but are not parasitic.
Not obligatory - can complete its life cycle independently.
With a waxy blue-green sheen.
A structure that covers the sorus.
Descended from a single common ancestor.
A fern's midrib.
A fern's stem.
Group of sporangia.