Recycling propolis

Last year I photographed bees bringing propolis to the hives in summer and in autumn and it set me wondering about how they collected it in the first place.  So far I haven't been able to find a bee collecting propolis from a tree or plant naturally.  However, at my last inspection I had readied a nucleus hive in case I needed it to deal with swarm control.  In the end I didn't need it but I noticed that a bee was collecting and recycling some of the old propolis on the crown board.

I had time to set up the tripod and camera to record what was happening because the bee was making repeated visits to the nuc.  By watching closely and studying the videos I recorded I can see that the process is, not surprisingly, very different from pollen collection.  The bee first chews off a bit of propolis with her mandibles.

Then she transfers it to her front feet.

The next move is very rapid as she moves it back to the inside of one of her middle legs.

Then it is moved to the corbicula (pollen basket) on the same side

and patted into position.

Here is another sequence.

I have blended together three short slow-motion video clips to show the movement in action.  Even though it is slowed by 4 times, the first transfer from the front leg(s) to a middle leg is still very quick.  Patting the propolis into the corbicula is slower.

Although this was a very warm sunny day the propolis was old and was probably harder than fresh propolis, so presumably easier to manoeuvre without getting plastered in it.  I still want to find a bee collecting fresh propolis on a hot day to see how it is done.  My guess is that the technique will be similar.