Leafcutter Ant Fungus
Leafcutter ants are different than most other ants when it comes to their source of food. Most ants feed on sugary substances to obtain carbohydrates, and greasy substances or meats to obtain protein. Not so with the leafcutter ants. Leafcutters primary source of food is fungus.
This process begins with leafcutter ant workers bringing pieces of leaves and other plant materials back to their nest. The collector ants do not eat this plant material since they are not able to digest all of the nutritional compounds in the plants they gather. However, these workers do get some nutrients from the juices in the plants they harvest. Other workers meet the collectors at the nest entrance and accept the harvested plant materials. The workers chew the larger pieces into smaller pieces. The small pieces mix with the ant’s saliva to produce a moist substance that is deposited into special parts of the nest called fungus chambers. As the fungi in the fungal chambers grow and reproduce, enzymes are secreted that produce sugars and proteins that the adult ants and larvae eat.
The production of fungal gardens is an amazing example of mutualism – an interaction between two organisms in which both are able to survive and flourish. Field observations and research show that different species of leafcutter ants grow and consume different species of fungi. The mutualistic relationship between the ants and fungi does not end with the fungi producing digestible food for the ants. Bacteria grow on the ant’s body. This bacteria work as an antibiotic to protect the fungal garden from the effects of a parasitic microfungus that reduces the growth of the fungal garden. When ants are removed, alien fungus and other microorganisms will flourish. For these reasons, the ants are often described as both the farmers and pharmacists for the nest fungus. Leafcutter ant colonies are generally larger than other ant species’ colonies because of this close association with the fungal gardens.