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.
©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.
©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.
©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. 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.