Ant Colony
George McGavin
New Ant Home
The New Ant Colony
We’ve given our ants time to settle into the main nest area. Now we are ready to let them loose on the wider world we’ve built for them. It’s our first
chance to see how they organise the great collective endeavour they are famous for. Leaf cutting.
What we want to do now is to allow them to forage in a natural way, they would do in the real environment, and to do that, we need to join up the colony
with the virgin foraging lands beyond.
For the ants, it’s finally time to explore. Well, we’ve only just put the bridge in, and already we’ve got workers swarming up as far as here, so I don’t
think it will take very long for them to find the other end of this bridge.
Tentatively, the ants start to make their way down the bridge, although it’s not exactly a massive trail yet.
In the wild, you see them foraging all over the ground, but how far will they forage from the main nest?
Prof. Adam Hart
Adam Hart “Up to 100 metres, sometimes more, so you can follow these trails deep into the forest, and in fact, this colony was foraging deep into a
citrus grove, and you could follow them back for 100 metres or more.”
Our time-lapse cameras reveal that the trickle quickly becomes a flood. More and more ants head out to explore the foraging areas beyond. Now we’ll
have to wait to see how quickly they discover the plants and get their leaf-cutting operation underway.
But there are is one caste of ant we’ll hardly ever see out here, and that’s the soldiers. Unless they’re responding to a threat, they tend to stay
hidden deep within the nest. But we won’t get a full picture of how our colony works unless we can discover what these mysterious ants are doing.
Fitting the Tracking Device
So to find out, we’ve turned to technology. We’re going to use radio tracking devices to follow individual soldiers 24 hours a day. Joining us to
help is Claire Asher from the Zoological Society of London.
So, what we’re going to do is we are going to glue some radio-frequency tags onto their back, and Claire here is quite an expert at this. I’m
keeping well out of it, because I’m getting glued up myself.
Claire Asher
Claire Asher “So I just pop a little blob of glue. On their back.”
How heavy of these tags?
Claire Asher “They hardly weigh anything at all, and to an ant like this, they won’t even really notice it.”
I should point out that what we are doing isn’t hurting the soldier ants at all. How long would they survive in the wild anyway?
Adam Hart “These sorts of ants would only live a couple of months, often. They’re not long-lived. This is great because this is going to tell us
what these soldiers are doing, in the ground, which we don’t have a chance of finding out.”
So it is original research, this?
Adam Hart “Yes!”
Every tagged ant will emit a unique radio signal. And to detect those signals, we’ve placed radio receivers all over the nest. This will allow us to
track each individual ant and follow its every movement. We don’t know what the ants are going to do, or even of this experiment will work, but we’re
hoping it will give us new insights into the role of the soldiers in the colony.
While we’ve been busy, so have the foraging ants.
Just look at that, that’s barely 3 hours and already there’s an incredibly well-established trail.
Adam Hart “Yes, it’s teeming with ants. We’ve got a really nice floor of ants going this way without leaves, and these leaf-carrying ants going
back to that the big fungus garden over there, so it’s really, really nice.”
Now, it seems to me that a few of these are a bit confused, and some are going the wrong way.
Adam Hart “Yeah, I think we’ve got a little bit of a pinch point here. It’s so busy going in this direction that I think some of these ants are
getting turned around, but that’ll even itself out. Collectively, the ants carrying leaves are going in that direction, and the ants not carrying
leaves are going in that direction, but there’s always a few little errors.”
I feel I want to help the ones that are heading the wrong way and just go, “come on,” take you off and put you down there, bit of a head start.
These ants are finely-tuned leaf-cutting machines. A large colony can consume the same weight of vegetation per day as a cow. And they’re making
short work of the plants we are giving them.
It’s fantastic to watch them at work, because if you just look at it, glanced at it, it would just seem to be random, but it clearly isn’t.
Adam Hart “I don’t know if you can see up close, George, the way that they are actually cutting the leaf fragments. It’s really interesting. It’s
not how you might expect him to do it. They’re using those mandibles like scissors.”
The right-hand jaw is anchoring the leaf, and the other one is a bit more like a guillotine.
Adam Hart “Yeah, more like a blade going through.”
Leaf Cutting Ant
This method is incredibly powerful, enabling the ant to slice through even the toughest of leaves. Here we can see that same blade-like technique
being used on a very thick banana leaf.
Adam Hart “They’re anchoring themselves with the back feet, the back legs, so when they go around with this guillotine, they’re describing an arc of
a circle, and the bigger the ant, the bigger the arc. So you end up with a really nice mechanism to make sure that bigger ants carry bigger loads.”
Ant Structure
Over the next few days, our ants establish the leaf-cutting operation on an impressive scale. A marching column across the ropes, over the foraging
table and up the bridge. When they reach the top, the ants head down into the nest, making their way through the tubes towards the fungus gardens.
There, smaller and smaller ants chop up the fragments until it’s mashed into a kind of plant mulch. The tiniest ants of all then insert this mulch
into the growing fungus. There is nothing haphazard about this process. The structure we see here is carefully built by the ants.
The pattern of ridges and hollows allows them to fit more fungus into a confined space, and the hollows provide a safe place to nurture the brood.
The whole process is like a massive production line.
It just looks like a conveyor belt of green material just disappearing.
Adam Hart “It feels like the right sort of language to use. We’ve got an industrial cutting process going on here. We’ve got this conveyor belt
going back to the processing, the factory, if you like, back at the nest, so it’s a real machine at work.”
It’s this kind of collective endeavour that has made ants so fascinating to us humans down the ages. During the Industrial Revolution, when
factory life was transforming human society, the parallels were striking.
