Last night I had quite a lot of escapees and with 2 colonies side by side I had to do an Eeny, meeny, miny, mo regarding guessing to what colonies they belonged. I have Formica fusca.
I should have these colonies more separated apart, but regarding heat, moisture and no direct sun exposure this is the best place I have for them.
Since one of them has no queen, so they are condemned to go extinct, I give preference to the colony that has a queen so I dropped the escapees back into this colony's outworld.
And by mistake I've introduced them to the wrong colony. Twice. Oopsy Daisy twice! 
So I've ended having vicious fights every time one ant went from the formicarium to the outworld and met a stranger. And since they go one at a time, leaving the group protection, and that colony has only around 10 workers, this is a real danger for both the individual and the colony.
Boy do them fight hard!!! They just keep rolling on the ground and fight mercilessly.
I tried to break them apart by scooping them out of the outworld with a spoon and with the tip of a toothpick. Sometimes this worked, some others didn't, the winning aggressor just bit locked on the other one and I think I could see it attempting to inject formic acid into the other one's wounds!
So, hints to learn from my mistakes:
- Ants from that colony soon find the way back into the formicarium entrance hole and go back home. Strangers do not, they might go around the tube but know that's foreign dangerous territory and never enter, and usually walk around more on the far side of the outworld.
- The best way I found to break fights was by putting them in the fridge for 5 minutes. The single time I've tried this, when I've check back on them they had stopped fighting and broke apart.
So after cleaning this mess I was observing with no red filter on the formicarium and with a 30x watchmaker magnifying lens and I could clearly see the other ants realizing this one was wounded and in need of care.
I could even see it being grabbed by the antenna by another one, being forcefully dragged into a corner to be taken care of. Impressive!
Then it was surrounded by 3 other ants that "licked" it, taking care of it.
I've read about this behavior and know they secrete antibiotics and can save wounded mates.
I know ants do not lick each other as they have no tongues 
but this is the best way I can describe it.
Here's an interesting video about it:
https://www.youtube....h?v=pPXVNHWg5Ns
All the info I've found mentions "licking" but it does not properly name that behavior.
Does anyone knows the name of it, so I could learn more?
Thanks guys!
