The green empire: the weaver ants (Oecophylla smaragdina)

Ants aren’t for nerds only, they rules this world in giant numbers, colonizing all possible habitats and patrolling every inch of ground in search of food and territory. They’re true soldiers. Weaver ants conquered the green kingdom of plants, ruling among the leafy bastions of forest, in a very unique way.

Borneo, the third biggest island in the world, is the playground of this portfolio and story. Here forests are teeming with life where human population isn’t already too high in number and palm oil plantations didn’t arrived yet. I already found weaver ants in the past, when I visited Burkina Faso, and witnessed the leaf nests of Oecophylla longinoda, the african weaver ants, on mango trees. At that time I was too focused on spiders and frogs to actually care too much about ants, but I nevertheless gave them more than a glimpse and I was amazed on how they manage to catch and subdue large preys in no time.

Year passed, ants fascination grew exponentially (as well as for many other animals when knowledge mix with field experience) and finally I decided to visit Borneo for some “bugs hunt”. I had many stories in mind, that I wrote into my laptop as a to-do list: caves life, marvelous Amphibians, camouflage animals and many more… and among them, the weaver ants.

During my very first day in Borneo I was setting my things in Sandakan and I had some time to spend around, so instead of going to the blockbuster Sepilok orang-utan centre (and with a soft snob attitude I must admit), I headed with my colleagues to visit a piece of forest called “Rainforest Discovery Centre” where I found they have a very nice botanical garden at the entrance and a super nice forest behind it. Here the ants were of course everywhere, weaver ants included.
Here into the primary forest weaver ants roam the green layer from a few centimeters from the ground to the highest leaf. A colony can build hundreds nests of folded leaves and they can even reach a vast area touching 1600 square meters of ground and more than 20 trees.

One of my first encounters was a typical sight for this species: a group of workers tying a Camponotus sp. to a leaf, subduing it not with stingers like many other ants, but they firmly hold their position on the foliage while tearing the prey apart, dislocating the appendages and thus debilitating and killing it. Only rarely some appendages break, and it’s really possible that the acidic secretions the ants deliver have some toxins as well.
During my trip in Borneo I encountered O. smaragdina quite often, even in towns and among lodges, where they seems to adapt to artificial illumination, gathering around them at night to hunt for insects attracted to the light.

Then into the mangrove swamps around Kota Kinabalu I also witnessed the complete leaf-folding and sticking behavior, thus almost completing my work about these amazing ants. I was amazed to see how workers stretch their bodies to hold the leaves and how other ones come with the tiny larvae to secure the leaves together with silk. Funnily, this is perhaps the only child labor I would enjoy to see in my life.

When adult, weaver ants are partly vegetarian and they often drink the sap coming out of trees or, even more fascinatingly, they actually farm animals like plant hoppers. They protect them, even making pavilions of leaves around them against bigger predators. I wasn’t able to witness such behavior, but luckily enough Borneo’s still there and I’ll have time to go there again in the future!

My real stroke of luck was when pushed by never ending curiosity I raised a folded banana leaf near a visitor centre and I found something very hard to find: a freshly de-winged queen, with just a bunch of eggs and larvae. She was over them, in a protective manner that only mothers can understand, standing against the big intruder and fighting against her fear to run away. That is called “a foundation”, a really hard thing to find from what I know. In weaver ants polygyny (more than one queen into the same colony) is well documented, but in this case the lady was all alone, no leaf nests around, so this was the beginning of an empire to come. With great sensitivity I placed my flashes around, raised again the leaf for a few moments and after some shots I left the queen to her destiny, wishing to her a long and prosperous dominion over the green world.