Honeybees forage tree buds and wounded bark for sticky resin, carry it home in their pollen baskets, and mix it with wax and a little saliva and pollen to create propolis — "bee glue." Workers pack it into cracks, gaps around the entrance, and even coat cell walls with a thin antimicrobial varnish, effectively turning the hive into a self-sterilising structure.
Propolis composition varies by region because it depends entirely on which local trees — poplar, birch, conifer — the bees are foraging for resin.
Watch worker bees ferry resin loads to cracks and seams around a cutaway hive, packing them with propolis over time, then flip to an X-ray view to see the resin, beeswax and pollen layers inside every deposit.
Propolis is not pure resin — bees process foraged tree resin into a composite of roughly half resin, a third beeswax, and the remainder pollen and plant oils, applied wherever the hive needs sealing or sterilising.
Drag the sealing-progress slider to scrub through the colony's timeline, change crack density to add or remove gaps, adjust worker bee count, and toggle the composition X-ray to see each deposit's layered make-up.
Propolis has been used since antiquity — ancient Egyptians used it in embalming — and modern research keeps confirming its broad-spectrum antimicrobial properties.