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I started beekeeping in 2018. My first bees were everything a new beekeeper could wish for: gentle, good honey makers, and more importantly, in top health. For two years, my small colony of 20,000 female worker bees and one queen thrived and doubled. By eavesdropping on them, I would hear their gentle buzz or see a few workers braving the chilly spring wind to bring back pollen on their hind legs. However, one day in March 2020, the entrance of the hive was unusually quiet.

Sadly, and ironically, just as the world was facing Covid-19, my bees became infected by a virus. This time of year is too cold to open the wooden hive where the colony lived, so only later would I discover hundreds of dead bees inside the hive and that this macabre sight is one symptom of chronic bee paralysis virus (CBPV). In less than a month, my colony lost 70% of its worker population. It was too small and too weak to recover.

I felt helpless, witnessing the collapse of my first colony. For this virus, there is no cure.

CBPV is one of the thirty-one viruses known to affect honeybees. We don’t fully understand the mode of transmission of viruses in honeybees, but we know a potential culprit. Varroa destructor, a small mite not bigger than a pin head, feeds on the haemolymph which is the equivalent of blood in adult bees and larvae. It is one of the biggest threats to honeybee populations worldwide. Heavy mite infestations weaken the immune system of bees, making them more susceptible to virus attacks. The mite, a known vector of honeybee viruses, also increases the spread of infections by infesting other colonies.

Some beekeeping techniques and commercial treatments minimise mite infestations, but there is yet no vaccine or treatment for bee viruses.

Why should we care?

The decline of honeybee population is concerning because they are critical for agriculture, food security and biodiversity. Through pollination, honeybees contribute to the production and quality of around 75% of the food on our plates. Just in Europe, 600,000 commercial beekeepers economically depend on honeybees.

Along with wild pollinators, honeybees also contribute to the stability and biodiversity of our ecosystem, with 88% of flowering plants relying on them to reproduce and survive.

The genius of jelly: a natural preservative

I joined the Maori lab at University of Cambridge as a beekeeper and scientist specialised in DNA and RNA chemistry in 2021. Dr Eyal Maori discovered in 2009 that feeding honeybees with short RNA fragments from a certain virus confers viral resistance. When treated colonies are exposed to this virus, they are less susceptible to disease and death. The durable immune response triggered in honeybees by the RNA fragments is similar to how vaccines work. The group also found that months after the treated bees had died and been replaced by new worker bees, colonies remained strong and showed resistance against the virus. This suggested that worker honeybees naturally transmit RNAs to other members of the hive and so resistance is somehow passed on to the next generation.

There is a culprit, however. RNA is an unstable molecule that degrades within a few hours in a non-sterile environment, so how can bees share RNA? To share RNA amongst members of the colony, bees have developed a natural delivery method through a substance fed to all members of the hive: the royal jelly. This jelly is secreted by specialised glands in the heads of worker bees to continuously feed the queen and young larvae for their first three days. It contains proteins and other molecules that preserve the RNA.

We don’t know of any organism that shares RNA like bees do.

Further understanding and harnessing this RNA transfer between bees can help us develop bee vaccines. Unlike classic vaccines that work by providing weakened version of the virus, this system provides long lasting immunity for generations in the hive. This can also lead to the development of commercial bee vaccines.

My hope is that other beekeepers like me do not wake up one day to see their colonies devastated with a viral infection that they can’t cure.

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