Danger for ants
Ants seem to be attracted by carbon dioxide because their prey emits CO2. This can result in an death trap!
CO2 accumulates in lower parts of the container if now air movment is provided. an example: I put too many fruit flies in a plastic box. The air supply is located too high. Soon the ground will be covered with a thin layer of carbon dioxide, but not thin enough for the small Lasius Niger to breathe. They will feel very tired and lay down.
One can see that they aren't dead because the legs are not tightened but they still move them slowly. An where there are many ants and prey many more will follow eventually and produce even more CO2. To my astonishment some ant tries to carry out one of her sisters. It is uncertaint if she will succeed.