von Kale^^ » 20. Feb 2010 14:45
The problem with dying could be that they are NOT to be kept in a closed capsule or even a cotton-sealed test-tube, because their strong odour is toxic for themselves in large concentrations, just like with Formica rufa and some other anthill-making species that live in Finland and Europe. So if you plan on keeping this species Lasius umbratus, you will need a good ventilation and a big formicarium when the colony grows.
A bunch of queens of this species had been caught by a finnish ant-keeper a few years back and he witnessed only one queen survive after sealing their test-tubes with a cotton ball. After he noticed that the other queens were dead he luckily figured out that the airtightness was the problem there and quickly re-opened her test-tube and the queen continued to live.