Ask a non-beekeeper what bees collect when they forage and you will probably hear of nectar and pollen. But few will mention propolis. Yet propolis is an essential material bees use to maintain and protect the hive.
To be factually accurate, bees don’t collect propolis. Instead, they create it inside the hive from other substances they have foraged.
Read the full article here: Sticking with Propolis — PerfectBee