Last week I was intrigued by this chocolate brown
and coffee brown.
Having looked them up I think it is likely that both are from clover. Some of the brown is flecked with yellow but looking closely the yellow seems to be bits of stamen from the flowers.
This blue is probably from rosebay willowherb (Epilobium angustifolium).
This blue is darker with a sparkly appearance. I'm not sure where it comes from, possibly also willowherb. I wonder if it might be great hairy willowherb (Epilobium hirsutum) but can't find any reference to its pollen colour.
Apple green is from meadowsweet.
There is still some yellow pollen coming in.
I am not sure about the source of the white. Himalayan balsam pollen is white but even though they get covered in it the bees don't seem to collect it - they just go for the nectar.
Unlike bumblebees, honey bees usually collect only one pollen at a time so the pellets in their pollen baskets are all of one colour. Here is a rare exception from this morning. This bee changed from blue to yellow mid foraging trip.
It is fascinating that the bees also go to the trouble of keeping pollen from different flowers stored separately. There must be a reason for it.
Although pollen from many flowers is orange or yellow, it comes in every colour in the spectrum plus black, white, grey and brown. Pollen from different sources is sometimes put in the same cell, presumably when one source runs out before a cell is full.
It is also interesting that pollen cells are never filled to the brim, unlike nectar and honey cells. I guess it is so the pollen doesn't fall out and the bees have room to work with it.
I have watched returning bees with pollen loads walking backwards and forwards over a comb, sniffing all the cells containing pollen until selecting the right one.
The bee scrapes off the pollen into the cell herself, using her to back legs, rather in the manner in which I take off my wellies. Unfortunately the process doesn't show up on a photo but here she is just before and just after.
Honey bees probably collect lots of different pollens because the nutritional content of the pollen varies. A wide variety provides them with a healthy diet and offers all the amino acids, trace elements and micronutrients they need.