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What is propolis?
Propolis is the sticky 'glue' used by honeybees. Propolis is often coloured dark brown, but it can also be yellow, green or red.
How should I pronounce propolis?
To rhyme with how you pronounce acropolis!
Where does it come from?
Plants are literally rooted to the spot where they grow. This means that if attacked by an enemy, plants cannot run for it. Plants have therefore evolved chemical defence systems to protect themselves. These include toxins, bitter tastes and stinging repellents. Tender buds would provide tasty snacks for insects unless protected: often a plant protects its buds with sticky gums When a tree is wounded it secretes resin around the wound as the first stage of the healing process. Humans also derive great benefit from these powerful plant chemicals: there are thousands of examples. Everyday substances include aspirin (from willow trees), penicillin (from a fungus), caffeine (from coffee) and menthol (from mint plants). Many medicines are derived from plants.
Like humans, bees also harvest powerful plant chemicals. They do it by collecting tree gums and resins and placing them in their nest.
How do bees collect propolis?
The bee bites off scraps of plant resin with her mandibles and packs them into the corbiculae (pollen baskets) on her hind legs. Each corbicula can carry about 10 mg of propolis. Because of its stickiness, propolis gathering is a slow business: it can take an hour to fill both baskets Back at the hive, unloading can take another hour. Propolis is only collected when the temperature is above 18Â°C Sometimes bees collect man-made materials and use these in the same way as 'real' propolis. For example bees will collect drying paints, road tar or varnish. Presumably to bees these substances have a consistency and strong odour similar to plant resins.
Do all honeybees collect propolis?
No: Apis cerana is one honeybee species that apparently does not use propolis. Different races of Apis mellifera use propolis to different extents; the Caucasian race is a particularly enthusiastic collector.
So what exactly is in propolis?
It is not possible to define propolis any more than it is possible to define honey: it all depends what is available to the bees. In general. propolis consists of resins, waxes, volatile oils and pollen, also vitamins, minerals and plant chemicals like flavonoids. The problem for people marketing propolis commercially is to obtain a standardised product.
What use is it to humans?
Propolis has long been used as a medicine. It is commonly available as an ingredient in toothpaste, soaps and ointments. Many people value propolis for sore throats and toothache -take a pea-sized piece of propolis and keep it in your mouth. A tincture of propolis is made by dissolving it in alcohol.
Is propolis antibiotic?
Yes, it has been proved that propolis kills bacteria. There are many claims for the medicinal properties of propolis.
How do you harvest it?
To encourage bees to produce conveniently-sized propolis, place a perforated grid in the hive. This is similar to a queen excluder but with smaller slots - not more than 6 mm. The bees will seal up the slots with propolis. Take out the grid and put it in a freezer. When cold enough, flexing the sheet will cause the propolis pieces to drop out. It might be possible to harvest 50 g per hive per season this way.
How much is it worth?
Current (1997) world price is around 10 US$ per kg.
WHAT DO BEES USE PROPOLIS FOR?
Â· Apis mellifera honeybees use propolis to keep their homes dry, cosy and hygienic. The propolis coating makes the walls of their nesting place waterproof and draughtproof. Propolis is used to seal up any cracks or gaps where micro-organisms could flourish. The volatile oils in propolis must serve as a kind of antiseptic air-freshener.
Â· As a building material to decrease the size of nest entrances, and to make them smooth for passing bee traffic.
Â· A thin layer is used to varnish inside brood cells before the queen lays eggs into them. Presumably this provides a strong, waterproof and hygienic unit for developing larvae.
Â· To embalm bodies of mice or other predators too large for them to eject from the nest: these would otherwise decay and be a source of infection.
Â· Apis florea, one of the Asian honeybee species, uses rings of propolis (like grease bands) to coat the branch from which its single-comb nest is suspended to deter predators.