Is this even possible ?

[SDM]

Last Friday I prepared a queenlessness nuc ready for some grafting. Grafted on Sunday with a 14/20 acceptance and then again yesterday morning.
When I checked on them yesterday eve. I had 0/20.
I checked the other frames to see if I'd missed some queen cells and noticed some eggs and then, there she was.... An apparently Amm queen, unmarked and unclipped (quite a pretty thing). The nuc was made up from a hive of Buckfast, so she stands out in colour and size.
Now I have a few similar looking queens that came with this years swarms, but they are all marked and clipped (I checked them all to be sure they were home).
Now I'd usually just presume I've made an error in records and manipulation, but I didn't have a queen in that condition to make the mistake with.
So, has a queen moved into the colony ? Is that even possible ?

[The Drone Ranger]

It's possible she has flown in from a nearby nuc or mininuc after a mating flight
I think its the most likely explanation if the queen you removed was clipped she cant have found a way back

[mbc]

More likely she came in with the "queenless "nuc. Multiple queens in the parent hive can be the cause, you think you've put the queen aside but there's another one unspotted, it's happened to me.

[busybeephilip]

Was checking some mini nucs yesterday with the intention of preparing 5 frame nucs, one where the entrance disc had not been turned after she started laying had disappeared . She had layed up the frame and brood was just starting to hatch so I could see what the new bees were going to be like in terms of color

I'd love to know why laying queens just vanish, its very odd. It could explain some of the thread above but I'd love to get an answer.

[Jon]

mbc. But if he had a second queen in the mini nuc they would not have started any of the grafts.
It must have flown in. This is quite common when you have a lot of mini nucs on a site with queenless hives.
I have had something similar happen 3 or 4 times this season at one of my sites.
One example was a queenless nuc I made up to put a queen cell into and when I checked for emergence a couple of days later there was a queen laying in it.
Another example was a hive which swarmed with a clipped queen when I was standing beside it.
The queen dropped a couple of yards in front and I put her in a roller back inside the hive and waited for the bees to return.
The swarm settled and did not return so I collected it an hour later and tipped it in front of the hive.
Turns out it had picked up a virgin from an apidea when it was in the air.
Last week I had a colony swarm and its queen was in a cage inside so it left without a queen.
When it settles I picked out 4 queens which were being balled which it had collected before settling.
I have 50 apideas on that site.

[SDM]

OK , I have a possible solution to this. I looked in again today and they're not all my bees. Roughly half look like the bees from Amm queens that mated amongst my Buckfast boys. They have Buckfast pattern but with much darker rings. I think they've been usurped(but without much warfare).
Last week I mentioned 3 queens gone from mating nucs, these nucs were shook out leaving just one mating nuc on the pallet. The next day, the mating nuc and the pallet it was on was just a big pile of bees as they all seemed to have moved into the remaining nuc. That night it rained and I didn't see them again( that mating nuc is now nearly empty)
Alls well that ends well, I've gained a sizeable Q+ colony and id never seen usurping in bees before I made up another queenless nuc today for grafting Saturday, but I bet I'll never beat "6 days from queenless nuc to laying queen"
I love that this hobby keeps throwing curve balls to keep me on my toes.

[mbc]

mbc. But if he had a second queen in the mini nuc they would not have started any of the grafts.
It must have flown in.

Good point