Formica rufa queens have to murder a Formica fusca queen (and any supsicious workers) to found their own colony. They are pretty badass, they know how to kill stuff.
And have you ever seen Formica fusca queens? Those ants aren't dumb. If they realize they get attacked by Formica rufa or sanguinea they leg it - they just abandon their nest and carry as much of the brood as possible with them and the queens can run even faster than the workers (which are already pretty speedy). It's can be a serious PITA to catch F. fusca queens after their nuptial flights because they are so fast.
Also there's a massive array of myrmicine species where the queen actually has to HUNT food to feed her first brood because she doesn't have the resources to get them to pupa stage on her own. Prominent examples of those are Myrmica (european fire ants), Myrmecia (australian bull ants) and Odontomachus (trapjaw ants).