How much propolis does a colony produce per year?

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Correct answer: 3 (50 g – 150 g)

Only a small proportion of foragers collect propolis (1% or less). By weight, this is indeed the most marginal type of collection in a colony: on average 50 to 150 g per year; however, the most “propolising” honey bee subspecies, the Caucasian bee, may collect up to 1 kg. Nothing is known about the criteria on which bees base their choice of resin sources.

Collection is not easy. First, the bee must detach the resin from the plant, extract it if necessary from the hairs covering the bud or leaf, and sometimes fragment it using the mandibles. Once freed, the resin particles are worked with the mandibles, then taken up by the forelegs, passed to one of the middle legs and from there to the corbicula of one of the hind legs. The bee then takes off and sometimes circles around the source to land again and complete the load; this “pre-flight” may allow it to assess the weight of the load already collected. The whole process takes from a few minutes to up to an hour. Some propolis may also be transported between the mandibles.

Back at the nest, the bee goes to the place where the propolis is to be deposited; it is unloaded there by other bees. The forager is in fact unable to remove the resin from its corbiculae by itself. Removing a load of propolis is a lengthy process: it can take from one to seven hours, and several workers may simultaneously collaborate in unloading a single forager. If unloading is too slow, the forager performs trembling dances, exactly like nectar foragers; these dances recruit additional propolis receivers.

To explore further:

► Propolis