I was watching the bumblebees navigate some freshly opened Rose of Sharons in my backyard yesterday and I noticed that after a short while, the bees were so covered in the yellow pollen that they had to rest and remove some of it before they could continue their foraging.
This made me wonder – is there a trade-off point for pollinator pollen collection where the effort to keep moving is greater than the cost of stopping to unload the sticky pollen grains?
Also… pollen seems to do a terrific job of sticking to things, so – how do the grains keep themselves separate?
Many insects use the pollen as a food source, so they’re happy to be so covered in pollen that they have to take time to scrape it off their bodies and stuff it into the pollen sack. Bumblebees do this. They’ll feed the pollen to their larvae, back in the nest.
On the other hand, orchids and milkweeds attach a clump of pollen each insect. The clump is more or less a burden to the insect and often (usually?) not useful to it.