This week we went to the UK National Honey Show in Weybridge, Surrey. They always have a great range of speakers on various aspects of bees and beekeeping, and for me the stand out talk this year was an update by Dr Alan Bowman from the University of Aberdeen on his teams work on Transient Gene Knockdown with Dr Ewan Campbell as a means of treating Varroa mites. The really good news is that they are preparing to start trials with their a new treatment using a technique called double-stranded RNA-interference (dsRNAi) as a method of silencing gene expression in Varroa as soon as next spring!
Varroa mites come from Asia where they co-exist with the Asian Honey Bee who have developed various techniques to deal with them over millennia. Unfortunately, they were spread by human activity out of Asia and into Europe, the USA and beyond where they started attacking our local European Honey Bees who have no natural immunity or other means of dealing with these nasty pests. The mites are now endemic, and have practically wiped out all feral colonies, meaning that without beekeepers, the European Honey Bee would probably be extinct.
The work by the team at Aberdeen University is focused on killing the Varroa mites effectively without harming the host bees in any way. All the methods we use currently target the small proportion of adult mites riding around on the bees and that's after they have already bred and done their damage to the growing larvae inside the honeycomb cells. To really deal with the mites, we need something that can target the mites inside the bee cells before they attack the larvae and do their damage.
Dr Bowman's team have been sponsored in their work by a local company Vita and are targeting specific gene sequences unique only to Varroa mites at critical points when they move from one development stage to another. The idea is to introduce strands of modified RNA into the mites when they initially feed on the royal jelly in the cell intended for the bee larvae. Then at the point where the targeted genes would be activated, the new RNA blocks that process and the mite dies.
My guess is that they can introduce the RNA in the form of syrup fed to bees that passes harmlessly through them and into the royal jelly fed to all bees at the larval stage. Because it's using RNA specific only to the mites, this method should be extremely effective and safe as it's only impacting key proteins and enzymes unique to the mite and nothing else. By picking those areas key to the mites transition from one stage to another, its also virtually impossible for the mite to develop resistance...