Collecting Resin
Verhalten der Bienen
Bees collect bud resins from poplar, birch, alder, willow, horse chestnut, and conifers, and carry them in the pollen baskets of their hind legs, just like pollen.
Bees collect bud resins from poplar, birch, alder, willow, horse chestnut, and conifers, and carry them in the pollen baskets of their hind legs, just like pollen. The buds are visited preferentially in the late afternoon, when the resin is soft. The forager cannot unload the sticky load herself; house bees take it from her.
In the hive, this resin serves to seal cracks, narrow openings, stiffen cell edges, and coat the hive walls. Gaps up to about five millimeters are sealed with pure propolis, larger ones are stretched with wax. Larger intruders that cannot be carried out are entombed with it. The color reveals the origin: alder yellow, horse chestnut reddish, poplar brown, birch black.
How strongly a colony collects resin depends on stock and location and varies considerably; this is more a breeding trait than a matter of management. It is collected throughout the flying season, with a clear focus in late summer. Anyone planning to harvest it should know that residues from Varroa treatments and pesticides can accumulate in this resin.