Put it back!
That’s not your bit of grit. Another bee laboured long and hard to seal up that bamboo tube so it would keep their offspring safe through the cold winter and safely into next summer.
You are supposed to go and find pollen to take back to your hole – not take it out of someone else’s.
I have been watching my bee hotels lately and was pleased to see lots of little black bees with yellow scopa – a new species for me and my bee hotels!
My new arrivals have some different behavioural traits that we don’t associate with the hard working industrious bee.
I think they are Heriades truncorum and although they look quite cute and are only about 7 mm. long they are of a dubious, moral character.