Chester Zoo 

Leafcutter Ants

Leafcutter Ants (Acromyrmex octospinosus)

A problem faced by all plant-eaters is that plants are extremely difficult to digest. Many animals, such as cattle, overcome this by using bacteria in their stomachs to break the plant material down, making it easier to digest. Leafcutter ants use a special fungus to do the same thing.

Worker ants carry plant cuttings back to the nest where they are chopped into even smaller pieces before being laid out in the ants' 'garden'. The soldier ants protect the workers both inside and outside the nest. Smaller ants then pluck tufts of fungus from other parts of the garden and plant them on the freshly processed plant material. The fungus is very carefully tended by the ants who will even destroy any foreign fungus which starts to grow in their garden.

The ant fungus breaks down the leaves and absorbs the nutrients from them. The ants then eat the nutrient-rich fungus. The benefit for the fungus is that it gets shelter and protection and the ants cultivate it, making sure that it continues to grow. This fungus only lives in the nests of leafcutter ants - it has never been found anywhere else. Without the ants, it would die.

Although the majority of ants in the nest are female, there will also be a few males, called drones. These do no work apart from mating with the queens. The queen's role is to lay eggs and 'manage' the colony with a series of chemical signals.