Three-way symbiosis for good gardening, according to an article in BBC News, 18 March 2004. Cameron Currie studies parasol ants – a type of leaf-cutter ant that cuts pieces of leaves from trees and use them as mulch in their fungus gardens. The ants feed on the fungus and keep their larvae in the fungus garden, so it is essential that garden is kept clear of disease. The ants weed out any diseased fungus and remove it to a rubbish dump outside the ant colony. They are also able to recognise spores of disease causing fungi and remove them from the garden fungus.

Like good gardeners they have a compost heap in a separate chamber next to the garden where they deposit deceased ants and garden fungus that is no longer useful. There is a special class of worker ants who regularly turn over the compost helping the waste material to degrade as quickly as possible. To prevent infection of the garden these waste manager ants are not allowed back into the main colony.

The most intriguing infection control is a symbiotic relationship the ants have with a bacterium. The ants allow it to grow on their body surfaces and the bacterium produces an antibiotic that suppresses the fungus garden disease. Together, the ants, the garden fungus and bacteria make up a three way symbiosis. The other intriguing aspect of ant study is how the ant workers are organised, as they “have no bosses directing operation or policing the gardeners.” Prof Nigel Franks of Bristol University commented: “If we can work out how the social insects manage their labour, I think it could give us some really deep insights for the organisation of our own factories, or networks or computers.”


Editorial Comment: The ants’ complex organisation and three way symbiosis are excellent examples of irreducible complexity. If any aspect of the social organisation or the symbiosis broke down the ants would rapidly die of disease. For the same reason the organisation and symbiosis could not have evolved one step at a time. The Biblical book of Proverbs tells us to study the ant, because “it has no commander, no overseer or ruler, yet it stores its provisions in summer and gathers its food at harvest.” (Prov.6:6-8). The reason ant colonies can function without any apparent hierarchy is that their organisation is built into them by their Creator. (Ref. arthropods, mycology, symbiosis)