Honey Bees, Trees and Propolis

Most of us realize that honey bees are important insects. They pollinate essential food crops, as well as make honey and beeswax. We know that honey bees need flowers to survive because they feed on nectar and pollen. We probably think of small plants, such as clover or dandelions, when we think of honey bee food. What is the role of trees in honey bee survival?  It turns out, a role as big as the trees themselves.

Here in the Southwest, mesquite trees are an important source of pollen and nectar for honey bees. In the northeastern United States, trees such as oak, willow, black locust and tulip poplar produce large amounts of nectar and/or pollen. Commercial beekeepers use their bees to pollinate almonds, apples, and citrus. Trees are significant food sources for honey bees.


Honey bees use trees as a source of other products, as well. When beekeepers open the honey bee hive, they have to use a special tool like a small crowbar, called a “hive tool.” That is because the honey bees produce a sticky, gummy material called “propolis” that they use to coat the inside of the hive. Propolis is made from plant resins the bees collect and carry in the pollen baskets on their back legs, mixed with materials from their own bodies, such as waxes.

Propolis Photo from Wikimedia, by Abalg (Adrian)
Propolis Photo from Wikimedia, by Abalg (Adrian)

Because I had just written a post about tree resins and ants, I decided to look into what is known about tree resins and honey bees. Although the existence of propolis has been known for a very long time, and many uses for it suggested, not a lot of scientific investigation has been done. It does appear, however, that honey bees are using the tree resins for some of the same reasons that ants do, namely to fend off disease organisms.

pine-tree-resinScientist Marla Spivak, who works at the University of Minnesota’s College of Food, Agricultural and Natural Resource Sciences department, has been working with a team to find out more about the anti-disease properties of propolis.

She has found that the honey bees in her area collect the raw material for propolis in the form of resin from birch and poplar trees, as well as some conifers. When they looked at the chemistry of propolis, they found some 300 to 500 compounds. The team is now separating the components and looking for individual compounds with biological activity against either honey bee or human disease-causing agents.

Turns out that trees are important to honey bees in more ways that we realized.

For more information:

Honeybees sterilise their hives by Matt Walker, BBC Earth News

Secrets of the Hive by Sara Specht University of Minnesota College of Food, Agricultural and Natural Resource Sciences

I also came across this article about helping the honey bees:

What Can a Lay Person Do?

Edit:  (Once again, we have a blog post inspired by a book. This week it is a children’s book, The Hive Detectives: Chronicle of a Honey Bee Catastrophe by Loree Griffin Burns and photographs by Ellen Harasimowicz. If you are interested in finding out more about the book, check Wrapped In Foil for a review and Growing with Science for related hands on activities for children.)

Source of book: The Chandler Public Library

3 Replies to “Honey Bees, Trees and Propolis”

  1. I think there’s much to be learned regarding the healing properties of propolis & bee products in general… they are fascinating creatures for sure. Thanks for the information & great photos!

  2. Seems like one of those things that has been known for a long time, but just hasn’t been investigated using modern techniques. I don’t envy the chemists any having to sort through hundreds or maybe thousands of compounds.

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