Weaver Ants

Champions of Cooperation

Weaver ants are reddish ants that live in the tropical forests of Africa and India. They are also found in Australia and the Solomon Islands. They are famous for the elaborate treetop nests they build. Weaver ants are champions of cooperation when it comes to building a nest. Even the recently hatched larvae pitch in! They provide the thread that stitches the nest together.

Weaver ants work to pull the edges of a leaf together to begin making a new nest.

Weaver ants work to pull the edges of a leaf together to begin making a new nest.

©J.Stafford-Deitsch/GLOBIO.org

It All Starts With a Leaf

The nest starts very simply. A group of worker ants finds a leaf that is soft and easy to bend. Several ants line up. Each holds an edge of a leaf in its mandibles and feet. Slowly, the ants pull the two leaf edges together. More and more workers join in. They link their feet and pull until the two leaf edges are nearly touching.

All Sewn Up

Weaver ant nests begin small but can sometimes become so large they connect branches of neighboring trees.

Weaver ant nests begin small but can sometimes become so large they connect branches of neighboring trees.

©G.Ellis/GLOBIO.org

Next, other worker ants carry larvae from the old nest and gently squeeze them between their mandibles. This causes the larvae to ooze a thin thread of silk. Then the workers get busy. Just like tiny tailors, they stitch the leaves together. In fact, another name for weaver ants is “tailor ants.” Treetop nests can become extremely large. Sometimes they even connect branches from two nearby trees.

Miniature Bodyguards for Trees

A giant weaver ant nest may look like it is damaging the leaves and branches of a tree. But weaver ants actually protect the tree they are living in. The ants act like miniature bodyguards for the tree. They keep other animals like birds, reptiles, and other insects from living in the tree or eating it. Sharing the same resource or living space is called symbiosis.

A Sweet Deal

Weaver ants have a “sweet tooth” that some creatures use to their advantage. Certain butterfly caterpillars produce drops of a sweet liquid called honeydew. The honeydew attracts weaver ants to the caterpillars. The ants then protect the caterpillars.

Weaver Ants Beware!

Weaver ant larvae produce a thin silk thread with their bodies. Weaver ants use the thread to sew leaves together to make a nest.

Weaver ant larvae produce a thin silk thread with their bodies. Weaver ants use the thread to sew leaves together to make a nest.

©G.Ellis/GLOBIO.org

Some caterpillars have a clever plot. By luring the ants with their sweet honeydew, they are able to enter the ants’ treetop nest and gobble up their larvae! Another arthropod also tricks the weaver ants. Certain species of jumping spiders look and smell like weaver ants. This allows them to enter the weaver ants’ nest without being noticed. Once inside, the jumping spiders eat the ants as well as their eggs and larvae.

Ant Eaters

Weaver ant pupae are harvested and sold as food in markets in Thailand and the Philippines. They are said to have a creamy flavor. People also eat adult weaver ants. Their taste is described as lemony or creamy and sour. The Dayaks in Borneo mix adult ants with rice for extra texture and flavor. Weaver ants are fierce biters, so people who harvest them have to be extra careful!

A Living Insecticide

Weaver ant workers take great care of the colony’s larvae.

Weaver ant workers take great care of the colony’s larvae. They feed them and are very careful when they move them. The larvae produce the special silk that holds the colony’s nest together.

©G.Ellis/GLOBIO.org

For the past 2,000 years, the Chinese have made use of the voracious appetite of weaver ants for other insects. They use them to control insect pests in their citrus orchards. To do this, they first put a weaver ant nest in an orchard. Then, they place bamboo strips among the trees to serve as "ant bridges." These ant bridges encourage the ants to colonize all the trees. More fruit growers are now bringing back this traditional practice of using weaver ants for pest control. It is a cheaper way of dealing with insects that have developed resistance to chemical insecticides.

Ants Can Fight Infection

People who live near weaver ants sometimes use them as a type of medicine. The ants have a strong chemical in their bodies called formic acid. The ants use the formic acid to protect their nests. People have discovered that they can collect a few of the worker ants and crush them to make a special mixture. The mixture is then used to fight infections. This kind of medicine is called traditional medicine. Studying traditional medicines like this may help scientists find new methods to cure diseases.