Propolis, a mass of plant resins built by honey bees inside their hives, has drawn attention in recent years partly because of its alleged (but as yet unproven) health benefits to humans. But, perhaps more important, it also shows health benefits to bees themselves. Created from resins and other oils and fats collected from trees, propolis helps preserve the structural integrity of a bee hive and protects against wood decay, fungus, and water.

Propolis has also been connected to benefiting honey bee (Apis mellifera) immune systems, saving energy that would otherwise have been used to protect against nest-invading beetles like Aethina tumida or parasites like the Varroa destructor mite, Nosema fungus, and viruses. In the past, some beekeepers have tried to keep their hives 'clean' of propolis, believing it impeded with honey-making activities. Today, though, scientists and beekeepers have begun looking at encouraging propolis production to help sustain healthy hives.

In a new study published in the Journal of Economic Entomology, three resea