I went through a lot to get my Camponotus pennsylvanicus. colony to stay in their 75 gallon tank.
Some things I learned along the way:
Too much humidity will send the colony out to look for a habitat more suitable. This also makes most barriers ineffective. Too little can also do this as well.
Lack of resources which was already suggested.
They can chew through almost anything, so it's best to persuade them to "stay". I've had them chew through layers of strong wire mesh within hours.
After all the frustration, I decided to simply make something that was designed specifically for them. (Store bought solutions not tailored to ants almost never work out the way you intend).
I made a plexiglass lid which was siliconed in place and epoxied over to harden the seal. I cut holes in the plexiglass so I could reuse byformica's mesh lids; which I highly reccomend if you can find them.
Note that they can still chew through this but with much greater effort. I typically will see a trail of ants working on a particular spot, which I can slowly try to figure out what is bothering them and remedy it before too many workers "help" escape.
Try to make sure there are no exposing tubing or overhangs. Anything they can get their mandibles on will prove unable to house them. Good luck!
Edited by iXvXi, March 8 2019 - 6:54 PM.