I was looking for my queen the other day. I thought I had found her with her yellow mark on her back, but she was really to small to be a queen. I thought it might be pollen, so I tried to gently scratch it off, but it wouldn't come off, although it surely was pollen. I later found the queen. Her mark has got smaller this summer. Not as large as it was in the spring.
Here is a comaparisment of the two:
(click to enlarge)
I laughed of the thought of having a lot of bees with the same spot on the back in the hive. It would be fun to find the queen then
I found a bee with almost the exact same spot in my other hive aswell