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> Leaf Cutter Ant
for kids - leaf cutter facts, fun & pics
Leaf cutter ants live in complex colonies beneath the tropical rainforest floor. Like all ants and all other insects, they have six legs, two antennas, and an exoskeleton. Their bodies are segmented into head, thorax and abdomen. They are most closely related to bees and wasps, both anatomically and socially.
Leaf cutter society is hierarchical and mostly female. The colony is founded by a queen, who is served by leaf cutters, foragers, gardeners, soldiers, and drones. Each of these kinds of worker has a specialized body to suit its function in the ant social scheme.
- Leaf cutters spend most of their time high in rainforest treetops. They have strong mandibles (jaws), with which they clip leaves into small pieces.
- Foragers haul these leaf pieces back to the colony. They travel in long lines, moving rapidly and carrying leaf sections that weigh as much as 30 times more than they do. In human terms, this is like carrying something as heavy as a bulldozer.
- Gardeners live in underground chambers where they cultivate fungus that provides food for the colony.
- Soldiers, the largest workers, defend the colony from attack by predators and invading ants. Their mandibles are strong enough to cut leather.
- Drones, the only male ants in the colony, are bred to mate with the Queen.
Whoa! Did you say they "cultivate fungus"? Yes! Leaf cutter ants grow their own food. They don't eat leaves, they eat fungus that grows on composted leaves prepared in underground gardens. Gardener ants lick leaves clean of unwanted fungi and natural antibiotics and then spread them out to compost. Ant fecal deposits seed the compost with the desirable fungus. The fungus is pruned at its spore production phase, when the gongylidia (swollen filaments) are fed to the colony.
Gardener ant saliva contains an antibiotic that suppresses both unwelcome fungi and the natural antibiotics that would inhibit growth of welcome fungi.
Gardener ants do not allow mushrooms to develop in their compost and weed out other kinds of unwanted fungi. They tend each garden for about four weeks until fungus is ready to harvest and then start new gardens. Large colonies include many garden chambers in all stages of production. In abandoned gardens, fungus matures into mushrooms and produces spores for further reproduction.
Why don't they just eat the leaves? Leaf cutter ants cannot digest cellulose, the material from which plants are constructed. Composting leaves breaks down their cellulose. Fungus feeds on the nutrients released as cellulose decays, converting them into simple carbohydrates that ants can eat.
Does the fungus get anything in return? Leaf cutter ants and their fungus food have a mutually beneficial relationship. Ants supply the fungus with leaves and eliminate other fungus that compete for the same compost. Leaf cutter ants and fungus are always found together in nature.
Symbiosis is the scientific term for a close, living relationship between two organisms. When both organisms benefit, their symbiosis is called a "mutualism."
How many leaves do the ants need to gather for their gardens? A leaf cutter colony consumes about the same quantity of forage in one day as a cow. Ants must travel considerable distances to find enough leaves for their gardens without doing irreversible damage to trees. (When trees are abundant, ants move on before completely defoliating a tree.)
Leaf cutter ants leave chemical trails behind them when they venture from their colony. Cutters and foragers follow these trails to find their way home.
Nevertheless, leaf cutter ants' impact on trees within their territory is considerable. Leaf cutters are often the major herbivores in their native rainforests, consuming more leaves than any other species.
What eats leaf cutter ants? Leaf cutters are an abundant source of food for many predators. Spiders and ant lions trap ants. Frogs, toads, and birds eat ants. Anteaters use their long, sticky tongues to extract ants from their burrows and swallow thousands at a time.
How do soldiers defend their colonies? Ants attack other colonies in competition for territories and resources. Soldier ants are magnificent defenders against this kind of invasion. They also launch and lead attacks.
The coffin fly is another serious threat to leaf cutter ants. The fly lays its eggs on the backs of foraging ants' necks. When the larvae hatch, they burrow into the ant and eat its brain. A special class of tiny worker ants called "minima" act as bodyguards for the foragers. They ride on the forager's backs, waving their pincers in the air, snipping at coffin flies.
What does the queen do? The queen is specialized for breeding. She also founds the colony and at first does all the work of tending eggs and gardens. Once she can devote herself to egg laying, she grows very large, several times the size of her daughters. Male drones' sole purpose is to mate with the queen.
A queen may fly up to ten miles to locate a suitable site for a new colony. She discards her wings and burrows into the ground where she creates a small chamber and lays a few eggs. She begins a garden with tiny fungus spores that she has carried from her birth colony in a special pocket in her head. She tends both the eggs and the fungus until enough workers hatch to take over. Once her colony is established, she can lay thousands of eggs every day.
A colony can be active for ten to fifteen years, foraging day and night.
The queen mates with only a few males and can store their sperm for ten years in a pocket in her abdomen called a "spermatheca." Drones have short lives and die after mating with the queen.
How big is a leaf cutter colony? Established colonies feed and house five to eight million ants. They contain an average of 2000 chambers, each of which is several square inches. Chambers are stacked up to three feet underground and may extend to 600 feet or more from their entrances. The soil carried by ants to the surface of the forest floor may weigh up to 88 tons. Leaf cutter colonies are found throughout the rainforest wherever access to trees is plentiful.
How many leaf cutter ants are there in the rainforest? Billions. Ants and termites make up about 30 percent of the biomass in tropical rainforests. Biomass is the term used for an estimate of the entire population of living organisms in a habitat--animals and plants, measured in terms of mass, volume, or energy. Scientists judge whether a forest is healthy based on the amount and variety of biomass. A huge population of leaf cutter ants may indicate a healthy forest ecosystem.
Species and Range. Leaf cutter ants range from Costa Rica to Argentina. A few species are native to the United States and can be found in Texas and other southern states. Leaf cutter ants are arthropodes of the Humenoptera order, Formicidiae family, Atta genus. Rainforest species include Atta sexdens, Atta cephalotes, and Atta rodona.
Are leaf cutters endangered? Leaf cutter ants are not endangered or threatened. However, in some regions they have become pests, feeding on the tender leaves of citrus, coffee, and cacao trees or ransacking stores of dried food--grains, beans, and cattle feed. When insects invade human habitat they become at risk of extermination.
Do people ever enjoy leaf cutter ants? People have found many ways to enjoy leaf cutter ants. For example,
- Rural populations in some parts of Mexico eat them (they're a good source of protein!).
- Some Indians use soldier ants to suture wounds. They let an ant bite both sides of a cut, then snip its head off its body. The head stays behind, jaws locked on the cut.
- An archaeologist who has worked for more than twenty years in the Guatemalan rainforest describes the long lines of foragers carrying their "little, green leaf flags straight up on their backs" as "cheerful."
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