Green Tree Ant

GREEN TREE ANT- (Weaver Ant)

The green tree ant found in Northern Australia is a type of weaver ant found in many parts of the world. The Australian species (Oecophylla smaragdina) is commonly referred to as either a green tree ant or weaver ant. They are called weaver ants because they weave a nest together out of leaves.

Location / Habitat
In Australia they are only found in the Northern regions. They occur in forested areas both in Northern Western Australia and also in the Northern Territory and Queensland. In Queensland they spread down the coastal fringe as far south as Rockhampton, and can often be found in fruit orchards.

Description
The colouring is obviously what distinguishes this green tree (weaver) ant from its "cousin" the red weaver found in Asia. Its body is a green or even a pale yellow, and its mandibles (Jaws)have 10+ teeth and they have 5 outer or maxillary palps segments, and 4 inner or labial palps segments.
For more detail on an ants anatomy click here
(Australian Ants Online website)

Nest Building

These unique nests are made by joining leaves together by using a silky substance produced from their larvae which they obtain from the nursery of an existing nest.
Worker ants transport the Larvae between their mandibles (Jaws) to the "construction site". The larvae is then with light pressure squeezed between an ants mandibles to produce the silk which is used to weave and stick the leaves together.

If one ant cannot reach the next leave to join it to the nest, the green tree ants will build a ant chain to slowly pull the leaves into and connect them to the nest they are building.
During construction the new nest is a hive of activity, scurrying ants everywhere, as these small creatures are a great example of how team work (working together) can produce a product much bigger and complex than any individual could hope to achieve.

The nest ends up being an oval (globular) shape up to 1/2 meter long but usually around 300mm, and because it is made from the leaves of the plant/tree it is constructed in, is often well camouflaged and hard to see. One colony can have any number of "individual" nests on one and nearby trees, making up their colony.

Attacking /Defence
Weaver ants will attack perceived intruders to defend their nest etc. Though they do not have a sting, after biting their enemy they secrete an acid (venom) from the tip of their abdomen into the wound to cause "discomfort" and irritation.
They hold their abdomen high in the air in aggressive posture.

Feeding
Green tree ants forage both for vegetation (eg nectar) and for invertebrates, both on the ground and on vegetation
The ants also feed on excretions from aphids and scale insects

Breeding

Like most ants they have a Queen Ant. This newly fertilised queen emerges from mating flights from well-established nests.
This Queen starts a small nest with her first batch from her eggs , and the cycle of breeding more workers etc starts to enlarge the nest.
The Queen Ant is located in one nest, but her eggs are distributed through the other nests of the colony.

Threats
One of the greatest threats apart from man are jumping spiders that look and smell like the green tree ants, so can penetrate the ants nest to eat both the ants and the larvae.

Click here for "The amazing ant-mimicking spider" website

Some caterpillars are also a predator of the green tree ant

Human & Scientific use
Due to large colony sizes and their appetite for small invertebrate, green tree ants have been used as "pest controllers" Oil from their abdomen has also been used by indigenous aboriginal people for sweetening water and medical purposes.
Commercial fruit croppers have problems with ant bites during harvesting
Due to the absence of bees in the top end of Australia, these ants pollinate the fruit flowers (eg mango & mandarins). This pollinate is necessary so you have fruit in the next season.