Montshire Minute: Leafcutter Ants

Originally aired during the week of September 21, 1998

Monday

When Montshire packed up and moved into its new building twelve years ago, thousands of tiny passengers went for a ride in the moving van. Thousands of leafcutter ants, that is. Montshire leafcutter colony, which can be seen in its see-through terrarium, has been a popular exhibit since 1984. Since that time the leafcutter queen has been dutifully laying eggs, insuring fresh generations of leafcutter workers. When a new terrarium was built for the colony four years ago, the queen continued her benevolent reign. But few other leafcutter queens have survived this long in captivity. So when we noticed the number of ants were dwindling, we feared the worst. But as they say in England, "The queen is dead, long live the queen!" So a new ant queen was introduced into the colony.

Tuesday

Changes in Montshire's leafcutter ant colony a few years ago suggested that something was wrong. There were fewer ants working on the leaves we were feeding them. The leaf mounds the ants create to grow food were getting smaller. Montshire staff and volunteers kept a close eye on the colony and concluded last week that the leafcutter queen was no longer active. The leafcutter ant queen is about the size of a newborn mouse and is rarely visible. She mates only once (Montshire's queen mated in 1983) after which she is kept busy laying eggs for the rest of her long life. Without the queen's prodigious egg-laying, a leafcutter colony perishes. Montshire's original colony was obtained from the Cincinnati Zoo in 1984. A replacement queen and her colony, also obtained from the same zoo, was introduced into the Museums' see-through terrarium three years ago.

Wednesday

Leafcutter ants are the only insects in our hemisphere that grow their own gardens. Native to South America, worker leafcutter ants emerge at night in huge numbers to scissor off leaf sections with their powerful jaws and carry them back to the nest. Then, workers of a smaller size cut the leaves into tiny fragments, eventually creating a moist mass of material riddled with tunnels that looks like a grayish-green sponge. (like the on your kitchen counter). On this garden grows a fungus which serves as the ants' food. The queen, an insect the size of a newborn mouse, spends most of her long life producing new generations of leafcutters. At Montshire, you can see these remarkable creatures at work in a new plexiglass terrarium. Our ants-in-residence are provided with fresh leaves each day - in the winter, they are fed leaves that have been frozen.

Thursday

Ants may be small, and much of their activity is hidden from our view, but without ants, in the words of entomologist E.O. Wilson, "The earth would rot." Ants help create soil and keep it fertile. Without ants, most animal populations would crash towards extinction for lack of food. Ant activity can really change the landscape in dramatic ways, too. A Dutchman living in British Honduras once described his attempt at planting a garden near a leafcutter ant colony. He arose one morning to discover his garden had been completely defoliated. In the center of the garden was a large peak of freshly excavated earth, into which moved an endless procession of ants, carrying bits of leaves over their heads like parasols. The leafcutter ant mounds are only the "tip of the iceberg" so to speak. Tunnels running deep into the ground are used for transportation and ventilation.

Friday

Imagine a society where everyone gets along, where everyone has a job, where no onegoes hungry. There is no welfare and no crime. No, we're not talking about a Marxist Utopia. We're talking about the society of ants. Leafcutter ants, which thrive in central and South America, have practiced a form of agriculture millions of years before humans got the hang of it. Leafcutters carry tiny bits of foliage to their underground nests. The activity of a colony can actually create small pathways on the forest floor. Entomologist E.O. Wilson equates the speed and activity of a worker ant to a person running a four-minute mile for 30 straight miles while carrying 500 pounds on his shoulders. While leafcutter ants seem to have voracious appetites for leaf matter, worker ants rarely kill whole trees. They shift from plant to plant, insuring there will always be a leaf supply available.