Propolis

Definition

A resinous mixture produced by honey bees (Apis spp.) from plant exudates—typically tree bud resins, sap flows, or other botanical sources—combined with beeswax and salivary secretions. Bees employ propolis as a construction material to seal small cracks and gaps in the hive structure, reinforce comb attachment, and reduce microbial load through its antimicrobial properties. The substance varies in color from pale yellow to dark brown depending on botanical origin and becomes pliable above ~19 °C, hardening at lower temperatures. Bees may also use propolis to encapsulate hive intruders too large to remove, a behavior termed "mummification."

Etymology

From Greek pro- (before, in front of) + polis (city), alluding to its use at the hive entrance.

Example

Honey bee workers forage for resin on poplar or birch buds in early spring, carrying the sticky loads back to the hive on their hind legs; once deposited, other bees manipulate the propolis with their mandibles to caulk gaps between hive boxes or coat the interior surfaces of nest cavities, creating a smooth, antimicrobial envelope that complements the structural wax comb.

Synonyms

• bee glue

Related Terms

• Beeswax
• Cerumen
• Royal jelly
• Bee bread
• honey
• eusocial
• Aculeate
• Apiary

Usage Notes

The term applies specifically to the material collected and processed by honey bees; other bees (e.g., stingless bees in Meliponini) produce analogous substances sometimes distinguished as cerumen or geopropolis when mixed with soil. Propolis composition varies geographically and seasonally with available flora, affecting its color, aroma, and chemical profile. In entomological literature, "propolis" is sometimes used more loosely for any resinous hive sealant, but precise usage reserves it for Apis products. The fungal genus Propolis (Ascomycota) is an unrelated homonym.