Article: Propolis

Propolis is a wax-like resinous substance collected by honeybees from tree buds or other botanical sources and used as cement and to seal cracks or open spaces in the hive. Its color varies from green to brown and reddish, depending of its botanical source. Honeybees will use propolis to attempt to seal any gap inside the hive that is smaller than 3/16" or 1/4" (5 mm or 6 mm) while they leave themselves a bee space of approximately 9.5 mm, or 3/8", larger spaces being filled with wax comb.

Traditionally, beekeepers assumed that bees sealed the cracks and joints of the beehive with propolis to protect the colony from the elements (like rain) and prevent drafts during the wintertime. More recent research suggests that bees not only survive, but thrive with increased ventilation during the winter in most temperate regions of the world. Propolis is now thought to:

1. reinforce the structural stability of the hive
2. reduce vibration
3. make the hive more defensible by sealing alternate entrances
4. Bees may also use it to prevent diseases and parasites in the hive.

Bees normally carry waste (dead larva, etc.) out of and away from the hive. However if, for example, a mouse chews its way into the hive for a winter nest and dies, the bees won't be able to move it out through the hive entrance. They have instead been known to seal the carcass in propolis, effectively mummifying the mouse.

Uses

Propolis is marketed by health food stores as a traditional medicine, and for its claimed beneficial effect on human health. Depending upon its precise composition (below) it may show powerful local antibiotic and antifungal properties. Also it is generally efficient in treating skin burns. Claims have been made for its use in treating allergy; it may stimulate the immune system, but some warn that it should not be taken if the user is likely to have severe allergic reaction to bees.

Old beekeepers recommend a piece of propolis kept in the mouth as a remedy for a sore throat.

Propolis is used by music instrument makers to better show the wood grain. It is a component of Italian varnish and was reportedly used by Stradivari.

Composition

The composition of propolis will vary from hive to hive, district to district, and from season to season. Normally it is dark brown colored, but it can be found in green, red, black and white colored, depending from the sources found in hive area. Bees are, after all, opportunists, and will gather what they need from available sources, and each hive will find its own individual sources. Therefore, the exact composition is never absolutely the same between any two hives, and various potential medicinal properties may be present in one hive's propolis, and absent from another; the properties of the propolis depend on the exact plant sources used by an individual hive, which the distributors of propolis and propolis products cannot control (a feature which may account for the many and varied claims as to its properties, and the difficulty of replicating scientific studies investigating these claims). Occasionally they will gather various caulking compounds of human manufacture, when the usual sources are more difficult to obtain.

"Typical" propolis has approximately 50 constituents, primarily resins and vegetable balsams (50%), waxes (30%), essential oils (10%), and pollen (5%). Propolis is sticky at and above room temperature. At lower temperatures it becomes hard and very brittle.

See also

• Discussion of bee space in the "Langstroth" section of beehive.