I have recently caught 2 M. Rubra queens and put them into 1 test tube set up.
Today while giving them some honey I found 1 of the queens sitting next to 1 egg. I found it a little bit weird, but I think it's already a good sign. Hopefully they both lay more.
I was just a little worried that there were more eggs, but the second queen could eat them.
It's possible that your queen intends to "overwinter" with her eggs, which apparently myrmica rubra can do. This means that the eggs will not hatch until the next season, given that they survive. If you want, you can also boost the queen with workers from her mother's nest, as in the wild, the daughter queens will overwinter in their mother's nest, and seek out their own home next season to start their own colony.
I've tried this, it takes a couple days for the workers to become friendly towards the queen if they are not introduced right after the queen is placed into her test-tube. I think this is because, if the queen is left inside her test-tube for a while, she creates a "nest smell" which workers will recognize as an enemy's smell. However, if workers are introduced into a fresh test-tube which the queen has just been given, they will acclimate almost instantly.
Currently raising:
Myrmica rubra (1 queen + ~5 workers)
Lasius niger (single queen + ~90+ workers)
Lasius neoniger (3 single queen + brood)
Formica spp. (Queen [likely parasitic, needs brood])
Formica pacifica (Queen)
Also keeping a friend's tetramorium immigrans for the foreseeable future. Thanks CoffeBlock!