The pollen basket or corbicula is part of the hind tibia of the back (posterior) legs of the honeybee. The bee moisten the fore legs with a protruding tongue and brushes the pollen that has collected on head, body and forward appendages to the hind legs. First, the pollen is transferred to the pollen comb on the hind legs and then combed, pressed, compacted, and transferred to the outside tibia of the hind legs. There, a single hair functions as a pin that secures the middle of the pollen load.
Honey and or nectar is used to moisten the dry pollen. The mixing of the pollen with nectar or honey changes the color of the pollen. The color of the pollen can identify the pollen source.
Apparently, Karl von Frisch and other bee researchers have observed that individual bees are more or less efficient in packing pollen into the pollen basket. It takes an individual worker bee from three to eighteen minutes to complete a pollen load and return to the hive. Bees may collect both nectar and pollen. Some plants, such as poppy, are only a source of pollen.
The pollen loads of the honeybee, Dorothy Hodges, published by Bee Research Association Limited, 1952