Other queens can be added, when they did NOT have founded an other colony, or rather did not have any workers yet. It is not save, if it will work, but it's still possible that the new queen will be accepted.
PS: I've got one myrmica rubra colony on my own and just added one queen to the main colony last week.
It is possible with Myrmica rubra but it is not a 100% sure. I added two small queens to my colony last winter (they have more change to be accepted when the colony is in hibernation, i read somewhere) and it work.
Yes ,If is Myrmica in hibernation ,you can changing queens ... I don´t know why ,but is more possible like when you do it now ,in summer - workers cannot accept her like queen ,but like food and this is not good for you
Oh ;\
- but it Lasius Flavus pologyn, or can have 2 queens?
. and if your lasius niger queen die, can u so set a new queen to them, so the colony don't will die?(:
no, they will stop eating when they are full.
you cant give to much, but leaving it in there more than 2 days is not good, just take any uneaten food out after 2 days.