Do they have a fresh sugar source? Any mold in the tube? Is it made of glass?
The test tube being made of glass changes something?
It's nothing too solid, but people used to say that Camponotus are sensitive to chemicals in plastics. Stuff like the PLA and ABS that are used today in 3d printed formicariums are pretty safe.
If you've enjoyed using my expertise and identifications, please do not create undue ecological risk by releasing your ants. The environment which we keep our pet insects is alien and oftentimes unsanitary, so ensure that wild populations stay safe by giving your ants the best care you can manage for the rest of their lives, as we must do with any other pet.
Exotic ants are for those who think that vibrant diversity is something you need to pay money to see. It is illegal to transport live ants across state lines.
Black lives still matter.