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.
In the mid 1800's, a certain Mr. Langstroth (who became an instantly recognizable name among beekeepers) made an interesting discovery. He had concerned himself with creating a bee hive specifically suited to the needs and behaviors of bees while also being more accommodating to the beekeeper. As he did so he noticed that bees built comb in certain gaps and fill other gaps with another substance. Eventually he observed and declared:
He had discovered bee space and designed his revolutionary beehive - the Langstroth - with that in mind.
The substance that bees use to fill gaps of 1/4" or less is called propolis.
Bees use propolis to bind the hive. It helps the structural integrity of the hive and has some fascinating properties.
However, it is not merely a glue. How many substances do you know that are anti-septic, anti-fungal, anti-biotic, anti-bacterial, anti-viral and anti-microbial?
Now THAT is an impressive resume for any substance. Small wonder that bees use it so heavily.
Propolis doesn't exist without the involvement of bees. The starting point for propolis is a deciduous tree. To protect their delicate buds that form in spring, trees excrete a resin that coats the buds. That resin has the same "anti...." characteristics we described above. Bees benefit from these properties and so they gather the resin and take it back to the hive.
Like most roles in the colony, specific foragers are tasked with the collection of the resin needed to make propolis. They collect it on warm days, because as temperatures fall (below around 5 degrees C) the resin hardens and so becomes more difficult to collect. As workers collect it, they mix it with wax secreted from wax glands. They then knead this into a small ball and collect it in the pollen basket. The gathering of propolis can take up to an hour before the worker is fully laden and can head home.
After propolis has been transported back from the source, it is transferred to a house bee. It is then deployed around the hive as needed.
Bees work hard to create propolis, as illustrated by this little worker...
If you search the web for propolis you will find much more about humans than bees! More accurately, you will find long lists of products offering health-related benefits derived from propolis.
The range of proposed propolis-related benefits is considerable. It has been used for health reasons for thousands of years. While there may not yet be direct, scientific evidence of propolis' health benefits many people have great faith in its powers.
Beekeepers have a mixed attitude to propolis. It serves bees in a several ways and a healthy beehive has propolis - period. This will vary according to several factors, one of which is the race of bees. Some races are more productive with propolis than others, with Caucasian bees being particular fond of the sticky substance!
The other side of the coin is that propolis can sometimes make a hive inspection rather "messy". Prying apart various components of the hive can be difficult if the bees have done a good job sealing the hive. Propolis' extreme stickiness will extract a small curse from every last beekeeper, whether at the hive or when noticed stuck to clothes later!
If you think your nice, new and very white beekeeper's suit will stay that way, then you are not taking propolis into consideration.
Get used to it. It's a badge of honor!
Despite these minor irritations, propolis is an essential part of your bee's world and its presence is a sign of considerable focus and effort by your bees.
Beyond the harvesting of honey and pollen, more beekeepers are becoming interested in the collection of propolis, some with a view to selling it. Specific equipment is available to help with this.
One more thing. As a beekeeper, the smell of propolis is one that you come to love!