49. What is Propolis? :

Kanna Das
6 days ago
3 min read

What is Propolis?

Propolis (sometimes called "bee glue") is a sticky resin that honeybees collect from tree buds, sap flows, and plant resins. Back in the hive, they mix it with a bit of wax and enzymes to make a powerful sealant and disinfectant.

Why Do Bees Use It?

Bees use propolis mainly for hive maintenance and protection, not just to stop wind or light:

Seal Gaps & Cracks—Bees fill any small spaces in the hive with propolis. This helps reduce drafts, block unwanted light, and keep out rain or pests.

Sterilization – Propolis has antimicrobial properties. Bees coat the inside of the hive with it, creating a “clean envelope” that protects the colony from bacteria, fungi, and viruses.
Hive Defense – If a predator like a mouse or lizard dies inside the hive, bees can’t carry it out. Instead, they cover it in propolis to mummify it, preventing decay and disease.
Structural Stability – It strengthens weak points in the hive and smooths rough surfaces, making the environment more uniform.

So while propolis does help reduce wind and light inside the hive, the main purpose is hygiene and defense.

Where Does It Come From?

Bees collect propolis from:

• Tree buds (e.g., poplar, birch, pine, eucalyptus, mango)

• Resinous plant saps

• Sometimes even man-made materials with resins or varnishes

The type and color of propolis vary depending on local plants — from dark brown to yellow-green or even reddish.

Why Asian Bees Use Less Propolis

Asian honeybees (Apis cerana, for example) don’t use as much propolis as European honeybees (Apis mellifera) because:

• Smaller colony size: Less need for sealing and reinforcing large spaces.

• Different nesting habits: Apis cerana often nests in smaller cavities or open spaces where heavy sealing isn’t as critical.

• Stronger natural defenses: Asian bees have co-evolved with pests like Varroa and tend to rely more on hygienic behavior (grooming, nest cleaning) than chemical barriers like propolis.

In short: Bees don’t just glue hives shut to block wind or light—propolis is mainly their medicine and construction material, collected from plants, used to sanitise and protect the colony. Asian bees evolved in a different ecological niche, so they rely less on it.

Reasons for propolis use

Bees spend so much effort sealing things up with propolis. Small cracks and crevices inside a hive are a problem for the bees for several reasons:

1. Drafts and Temperature Control

Bees work hard to maintain a stable temperature in the hive—about 34–35°C (93–95°F) in the brood area. Even small air leaks can let in cold drafts in winter or hot air in summer, forcing bees to use extra energy to fan their wings or cluster tightly. This stresses the colony and wastes resources like honey stores.

2. Moisture Problems

Cracks allow condensation, rain, or damp air to creep in. Moisture inside the hive can lead to mould, chilled brood, and poor bee health. Bees prefer a dry, well-sealed environment.

3. Pest Entry Points

Tiny gaps give easy access to pests like:

• Wax moths (lay eggs in cracks, larvae tunnel into comb)

• Small hive beetles (hide and breed in crevices)

• Ants (enter through gaps for honey or brood)

Bees find it harder to defend against pests sneaking in from hidden spots compared to the main entrance.

4. Unwanted Light

Bees prefer a dark, cave-like nest. Light coming through cracks disrupts their natural hive environment and can affect comb building behavior.

5. Sanitation Issues

Cracks are hard for bees to clean and patrol. Pathogens (bacteria, fungi, viruses) and dead pests can accumulate in these spaces. Bees seal them with propolis to sterilize and smooth out the hive interior.

Small cracks and crevices are bad for bees because they cause drafts, dampness, pest invasions, light leaks, and hygiene problems. That’s why bees “repair” them with propolis—creating a safer, more stable home.