Leafcutter ants and the Fungus they farm
Hardly a natural history documentary goes by without some mention of leafcutter ants. But there is good reason for their fame - these charismatic insects are incredibly successful because of their skill as gardeners. [4] |
As their name suggests, the 41 species of leafcutter ants slice up leaves and carry them back to their nests in long columns of red and green. They don't eat the leaves - they use them to grow a fungus, and it's this crop that they feed on. It's an old, successful alliance and the largest leafcutter colonies redefine the concept of a "super-organism". They include over 8 million individuals, span more than 20 cubic metres and harvest more than 240 kg of leaves every year. They're technically plant-eaters, with the fungus acting as the super-organism's external gut. |
But the partnership between ant and fungus depends on other collaborators - bacteria. Some of these microbes help the ants to fertilise their gardens with valuable nitrogen, by capturing it from the atmosphere (a process known as "fixing "). This joint venture with fungi and bacteria makes them a super-herbivore. The ants don't fall prey to insecticides produced by plants because the fungus deals with those, and the fungus doesn't have to cope with anti-fungal countermeasures because the ants break those down before plying it with leaves. As a result, both partners can exploit a massive variety of different plants, rather than specialising one any one type. [5] |