Propolis is a natural, resinous substance crafted by honey bees. Often called “bee glue,” this sticky material is fundamental to a bee colony’s construction and well-being. It serves various purposes, contributing to the hive’s overall health and defense.
The Raw Ingredients Bees Collect
Honey bees gather raw materials from their environment to create propolis. They primarily collect sticky, resinous exudates from plants, produced to protect the plants themselves.
These resins often ooze from tree buds, sap flows, or bark, forming a protective barrier against external threats like fungi, bacteria, and viruses. Bees source these resins from various tree types in their local ecosystem, including poplars, conifers, birch, alder, and cottonwood. The color and chemical composition of these resins vary depending on the botanical sources in a given region.
The Bee’s Production Process
The creation of propolis begins with worker bees’ collection efforts. They use their mandibles to scrape sticky resin from plant surfaces. The collected resin is then packed into pollen baskets (corbiculae) on their hind legs for transport back to the hive. Due to the resin’s stickiness, the foraging bee often requires assistance from other bees to unload its cargo upon returning.
Once raw resin is inside the hive, other worker bees take over processing. They combine collected plant resins with their biological secretions, including saliva and enzymes. Beeswax and sometimes pollen are also incorporated. This blending, with enzymatic action, transforms the raw material into propolis.
The final composition of propolis is a complex mixture, typically consisting of around 50% resins, 30% waxes, 10% essential oils, 5% pollen, and 5% other organic compounds such as enzymes, vitamins, and flavonoids. Its precise proportions and chemical makeup can vary significantly based on the specific plant sources available to the bees in their geographical location and the time of year. This transformation results in a pliable, yet durable, material essential for various hive functions.
Purpose of Propolis in the Hive
Bees utilize propolis for functions contributing to their hive’s structural integrity and overall health. They apply it to seal small cracks and gaps within the hive, reinforcing the comb and cementing frames. Propolis also reduces the hive entrance size, creating a more defensible opening against intruders.
Beyond structural reinforcement, propolis serves as a hygienic and defensive barrier. It possesses natural antiseptic properties, helping to prevent the spread of diseases by inhibiting the growth of bacteria, fungi, and viruses within the warm, humid hive environment. The bees also use propolis to embalm intruders that are too large to remove, mummifying their carcasses to prevent decay and maintain hive sanitation. Propolis is also used to polish the interior of brood cells, creating a sterile environment for the developing young.
Propolis also plays a role in environmental control within the hive. It helps to insulate the colony, maintaining optimal temperature and humidity levels, which are vital for the bees’ survival. By strategically applying propolis, bees can also regulate airflow within the hive, ensuring a stable and healthy internal climate.