These appear to be traps of some sort but I’ve no idea what for. Any ideas?

There must have been hundreds, if not thousands, of them hanging from the trees in the mountains of Majorca. Inside the mouth hung a small clear pastic container which had a couple of ‘beads’ in it. This looked as if it might be acting as bait but I can’t imagine how. The plastic bag hanging below the trap I would assume holds whatever is caught, but I never found one with anything in it.