Anyone who has visited the UGACR campus has experienced both the ubiquity and intense productivity of our leafcutter ants. Day after day, night after night, the tenacious leafcutter workers, all of whom are female, tirelessly carry leaf fragments back to their colonies on well-worn trails. Found only in the Neotropics, leafcutters have developed a novel way in which to feed themselves: through cultivation. The farmers of the insect world, leafcutters clip pieces of leaves from a variety of plants, which they then carry back to their colonies and use to cultivate a fungus. This fungus constitutes the majority of their diet. The ants and their fungus rely entirely on each other for their continued existence, exhibiting a type of symbiotic, or mutually beneficial, relationship called obligatory mutualism.
Leafcutters, however, are not the only ants that cultivate fungus as their principal food source. In fact, nearly 200 species of fungus garden ants exist, only 37 of which are leafcutters. Some of these symbiotic relationships between the ants and their fungi may even be as old as 50 million years. Remarkably, each of these species cultivates its own unique fungus found only in the colony of that species! While leafcutter ants grow their fungus in underground chambers, other fungus garden ants farm on decaying organic matter. Though you’ll find the majority of these fungus garden ants in the tropics, they may also occur in temperate and subtropical grasslands, with one species even occurring as far north as New Jersey. Fungus garden ants are inextricably linked to their fungi and are only one example of the many important ecological relationships to be observed here at UGA Costa Rica.
For more information check out:
- A Neotropical Companion by John Kricher
- Herbivory of Leaf-Cutting Ants: A Case Study on Atta colombica in the Tropical Rainforest of Panama by R. Wirth, H. Herz, R.J. Ryel, W. Beyschlag, B. Hölldobler
Guest Blogger: Lillie Kline, UGACR Resident Naturalist