A personal favourite of mine, rainforest ants are the most abundant insect in the tropics. If you stop for a moment, they will no doubt be the first creature you see walking along a tree trunk or through the rainforest leaf litter.
Rainforest Ants – Trap Jaw Ants
These tropical rainforest ants are found both the Amazon Rainforest and the Australian Wet Tropics. Trap jaw ants have impressive jaws that snap shut at the fastest speed known in the animal kingdom. Not only do they use their impressive jaws for catching food, but also avoiding danger.
They close their jaws with such a force that when closing on a solid object, such as a stone or a piece of fallen wood, they are catapulted into the air away from danger. These rainforest ants move about the forest floor holding their jaws at a 90 degree angle to their head, primed and ready. They can be found foraging at both day and night for a wide variety of small animals.
Weaver Ants (Oecophylla)
The dominant ants in the Australian rainforest, tropical Asia, and in the forest canopy over a large part of tropical Africa, weaver ants are a truly remarkable ant. They use their larval sisters like glue guns, constructing balls made from rainforest leaves by gluing leaf edges together. The larvae secrete a silk material ideal for the purpose. You can see these leaf nests when you take the cable car over the rainforest canopy to Kuranda from the city of Cairns in northern Queensland, Australia.
Although the ants don’t sting, they may as well. They bite into the flesh then spray acid into the wound making it feel like you are on fire. But you can get your own back, the ants are also known as lemonade ants throughout tropical Australia. Their bodies contain ascorbic acid (containing a high percentage of Vitamin C) and when you bite them off it releases a pleasant fruity citrus taste. Australian aborigines used these ants for a range of things including treating nasal congestion.
Weaver ants also live in Asia and were possibly the first biological control used to eliminate farm pests. You can understand why when you sit down to watch all the different animals they chop up and carry back to their colony.
Fire Ants (Solenopsis)
In the Amazon Rainforest, fire ants (in header image) have an ingenious way in dealing with frequent flooding. When the water level rises, ants can drown or become trapped in a small area. To counter this problem fire ants make themselves into living rafts to transport themselves, brood, and their queen across bodies of water (a video showing this is at the bottom of this page).
Like trap jaw ants, you can find fire ants in the Australian Wet Tropics as well as the Amazon Rainforest. However, unlike trap jaw ants they were introduced to Australia like so many other countries. In the Amazon they fit nicely into the ecosystem but elsewhere they displace species and can cause widespread harm, both to people (if you have every felt their sting) and to the surrounding ecosystem.
Sometimes when walking through the Amazon Rainforest, you will emerge from incredible biodiversity of thickly growing plants to venture into an area apparently planted by humans. The area is different as only one plant grows here, Duroia hirsuta. If you didn’t know to look for a species of Amazon Rainforest ant, you may be forgiven for thinking the gardens belonged to a forest spirit.
This could be quite terrifying if you were in the forest and had never discovered a garden of this nature before. The explanation is that the ants (Myrmelachista schumanni) weed a wide area around the Duroia hirsuta plant where they make their nest. The more Duroia plants there are, the more ants can live inside their stems. Room is definitely required as the colony can live for over 800 years. The ants systematically bite into non-Duroia leaf bases and insert their stings to squirt formic acid into the wound killing the plant (a bit like insect weeding).