[removed]

They track their way by scent markers. If you trace an ants journey another ant from the same colony will follow the exact same route.

To answer the second part of the question, no. Ants are INSANELY territorial. If the ant comes across another colony they will kill it. Instantly and brutally.

They also count and retrace their steps

this might be a dumb question, but do all ants of the same colony share the same scent?

Ants leave a pheromone trail behind them wherever they go. This helps them find their way back and tells others where they went. When this trail gets interrupted, they get lost until they find it again.

Occasionally ant colonies will merge if there is plenty of food to go around and nothing agitates them, but usually foreign ants are driven off or killed.

[removed]

In addition to the already mentioned pheromone trails, ants are also very good at exactly retracing their steps.

Experiments testing this exact question found that if they added stilts to ant legs on their return trip found that they overshot their nest by the corresponding amount that their stride was lengthened by the stilts, implying that they are effectively counting steps as they retrace their path.

If these normal methods fail and they get lost, they’ll then enter a spiral search pattern until they find the nest or a trail.

So this means that the ant in OP's example is likely out of luck? Because picking it up and moving it would not leave a continuous pheromone trail?

Would the ant just wander unless it happened back upon the correct path?

[removed]

Yes. Or more likely it would be attacked by something else.

[removed]

[removed]

There has been evidence recently of "megacolonies" covering vast areas.

And I mean vast. It's pretty mind-blowing, one single megacolony was found to cover over two-thirds of Europe.

So there's a small chance OP's ant may meet some friendly faces.

This some scientists discovered by giving the ants stilts. Think about that. Someone thought of it, someone designed and made the tiniest stilts, then someone had to put them on some ants.

Even with stilts, how did they prove that the ant counts its steps?

[removed]

With stilts each step is longer. The ants would make the same amount of steps thus overshooting on the return.

Yes, they are pretty much identical. Which is why they are so territorial: a foreign organism can take a pathogen to an ant colony and kill them all because they all have the same inmune system.

[removed]

[removed]

[removed]

Ants get around by a combination of pheromones (chemical signals) and a special internal sensory system that functions almost like a natural pedometer for them (in that—if I’m remembering this correctly—it essentially “unwinds” when an ant takes steps in one direction, and them “rewinds” when they take steps in the opposite, so in this way worker ants can essentially sense whether they are moving the correct direction with regards to their original path or not, and then in combination with pheromone “breadcrumb trails” can almost always retrace their exact steps back to the colony like clockwork). Of course, there are many ways these navigation systems can be thrown off, like a human moving an ant some distance from its original path, or cutting off one joint of each of their legs so that their internal “pedometer” system will register too few steps (this is how the system was originally experimentally observed; some ants had their legs shortened, and others artificially lengthened, and it would cause them to either stop short of the colony or walk too far very consistently. Not the nicest of experiments if you’re someone who feels bad for ants, but it did provide some valuable insights).

So to answer your question, no, if you were to move the ant far enough off course, it would not be able to find its colony again, or at least would have great difficulty in doing so most likely.

And ants definitely do not join other colonies. Ants are an example of a eusocial organism, meaning essentially that they live as a group of closely-related individuals that function as a cohesive collective, with only select members of the collective having reproductive privileges (the queen and the male drones), and the rest being strictly non-reproductive. It’s a social structure seen in ants, bees, wasps (although not all species of any of these), termites, some beetles, some marine shrimp, and (possibly most bizarrely) naked mole rats and another species of mole rat (the only known eusocial vertebrates), and probably others. Eusocial organism colonies are all the children of (usually) a single reproductive female “queen” and a small number of reproductive males (which in eusocial insects tend to be short-lived and literally exist solely to fertilize eggs and produce workers, as well as also being children of the queen themselves) and therefore are all genetically very close and almost act like the cells of a single “superorganism” more than individuals, as the workers can’t reproduce and have literally no other reason for existing except serving their colony’s needs. A worker ant can’t join another colony any more than one of your white blood cells could be put into another person’s body without being rejected and destroyed by the other person’s immune system; ant colonies are a packaged deal, and all other colonies are seen as competitors for the same resources that need to be destroyed on contact.

In addition, there is a side effect of that which is called the ant mill. Ants loose the track and start to follow the other ants if the path gets in a curl and start to walk in circles till exhaustion.

And crazy enough, they had a stilts, no stilts, and a amputated half the legs group, and the ones with half sized legs undershot their target. I just cant help but wonder if the amputated ants got the stilts afterwards.....

[removed]

Actually the answer to the second question depends on the species of ant, some will fight other colonies of the same species, some will merge with them.

[removed]

Sounds kinda brutal to amputate some legs just to triple-check that your hypothesis is correct.

This was found for desert ants, but I haven't heard of it being shown for other ants. Can any experts here say if it's thought that step counting is an important mechanisms for ants in general?

[removed]