I forgot that was how cuckoo bumble bees sometimes work I think it is only females that inhabit the nest after killing the queen
https://www.bwars.com/bee/apidae/bombus-vestalis
Nesting biology
After emerging from hibernation during April the mated female seeks out a small
B. terrestris nest with a few workers. The female sneaks into the nest and hides while it acquires the nest scent. It may dominate, or kill, the host queen and takes over the egg laying for the colony. These eggs produce only new
B. vestalis females and males, which take no part in the running of the colony, all work being done by the host workers.