Paus, the bees coming in with no pollen will have elongated abdomens if the bee is carrying nectar or water. The loaded with nectar bees kind of make a rough landing on the entrance due to the added weight. Loaded bees drag their elongated abdomen... Paus, I have a feeling you already understand everything I just text, I doubt I can teach the teacher; but newbees might appreciate...
I believe it was Ace in a previous text (long ago) that stated bees loaded with nectar land like loaded cargo jets, whereas empty bees land smoothly like fighter jet. I thought the analogy by Ace of bee to jets was an interesting way to describe.
Blessings