Join the Propolise Revolution!

After the summer honey flow one honeybee crop comes in full force – propolis! Managed honeybee colonies face numerous issues – high mortality, parasites, pathogens, pesticides and poor nutrition. Propolis appears to play a role in the answer to all these questions, and research demonstrates it can mitigate the effects. Propolis is even more diverse in origin than honey, and is the bee product with the most amount of immune system benefits for humans and honeybees. It is a substance that has the potential to create new values in beekeeping, and new relationships between beekeeper and honeybee.

Propolis has, at the same time, a long history of human use, as well as a current renaissance in scientific research and understanding of its role in natural healthcare. Propolis is collected from plant resins, using the immune systems of trees inside the hive. Conifers are famous for it, but alder, birch, chestnut and willow all produce resins. There are a number of evolutionary benefits associated with propolis collection, in terms of its associated genetics as well as the presence of propolis in the hive. I have come across some fascinating insights from the literature on propolis, which I share below.

Resin collection is both a genetic tendency and a demand-driven process (1). Some bees in the hive are specialised propolis foragers due to their genetics. Although propolis in the hive contains compounds from hundreds of diverse plant sources, bees individually return to the same site of propolis collection, implying it is a unique part of bee intelligence, as the foraging is individualised, unlike the collective systems needed to collect pollen and nectar (2).

Colonies with high propolis-collecting behaviours, and subsequent exposure to propolis, for example on the rims and inside of cells, and on the top bars, demonstrate a number of health benefits. These include increased hygienic behaviour, and increased pollen and honey stores (3). Also demonstrated in research is: increased survival of brood from egg to adult, greater weight of emerging adults from cells, and increased worker and queen longevity (4)(5).

Resin collection is a response to detecting pests and pathogens in the hive. For example researchers have introduced a fungal infection A. apis into hives, which only affects larvae, and found adult bees consistently increased their resin foraging to protect their larvae. This protection of the group makes propolis making a social immunity behaviour (6). This ‘self-medicating’ pattern has been demonstrated by increased resin foraging in response to Deformed Wing Virus (DWV) infection, where propolis collecting bees are able to maintain low levels of DWV despite increasing mite numbers (7).

Propolis exposure appears to enhance the bees natural immune response systems, alongside making the hive less habitable for microbes. Experiments have shown that nurse bees in hives with propolis exposure were more quick and effective at producing antibacterial peptides in the larval food in response to being challenged with a microbial infection. There was particular success against American Foulbrood and Chalkbrood (9)(8). In particular is the compound glucose oxidase, an antimicrobial substance produced by nurse bees and found in propolis (10).

Propolis is highly concentrated with antioxidant compounds such as flavonoids and polyphenols. Propolis also enhances the bees natural detoxifying pathways. Studies have documented the role of one particular compound found in propolis called p-coumaric acid. This chemical “increased expression of detoxifying genes” (11) and produced increased life spans after exposure to insecticides as well as beekeeper applied miticide (11). The antioxidant compounds increase resistance to oxidative stress. Accumulation of oxidative stress causes damage to cells and DNA, and is what constitutes the ageing process, explaining why bees exposed to propolis appear to live longer. It has been argued by researchers that some of the phenolic compounds in honey may be derived from propolis (12).