I love watching Bees do this. If theres a bee not moving very much then it's likely out of energy. I learnt on QI once that if you put a blob of honey in front of them they eat some and it gives them enough energy to fly home. I've tried it a few times and funny enough it does exactly that. Watching their little tongues lick it up fascinates me. Here are some pictures of it.

Fig. 01

Fig. 02
This one shows their head, I think it looks like they have one of those black dome cctv cameras on their head, that idea could be taken further.

Fig. 03

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