By Hans Van Veluwen

Northern Elkhorn ferns ( Platycerium hillii ) are colonising epiphytes.  Epiphytes are plants that live in symbiosis with other plants.  They derive no nourishment or nutrients directly from its host plant or tree.  They use them purely for support. Plants like ferns and orchids can be epiphytes.

Unlike parasites which grow on other plants but do derive some nutrients and nourishment from their host tree. Some epiphytes can grow to an enormous size weighing several hundred kilograms.

Symbiosis simply means working together for each others benefit. All of life is symbiotic. From the smallest gnat, bacteria, fungus, insect to the largest whale or elephant on this planet we all have the same life force flowing through our veins.  We are all brothers and sisters in life helping to form a living planet.  Take anyone of those life forms out of the equation and you actually send out shock waves through the rest of life. 

It's obscure, it's complex and we are only just beginning to understand that this is so.  For example, there is a basic three way symbiotic relationship between the clump of Elkhorn ferns (as per photograph), the host tree that supports it and colonies of insects that live in the fern clump...insects that call the fern home. 

These insects are mainly ant species.  At night time the ants leave their nests within the fern clump and forage for food to the extremities of the host trees branches. They are hunting down other insects that they use as a food source.  Insects like aphids, scale , thrips etc.  They catch these insects and carry them back to their nests within the fern where they eat them and excrete them and that forms the nitrogen rich fertilisers that the ferns depend on for their nutrient level. 

So by the host tree giving a home to the fern and the fern giving a home to the ants, the host tree has its own personal army of thousands of little soldiers which go out each night and stop the tree from being unduly attacked by other sap sucking insects. 

And there you have a basic working three way symbiotic relationship...equate that complexity to the rest of the rainforest!
For more details visit Hans van Veluwen on www.C3D.net.au