Varroa destructor mites are bad news for honey bees.
Not only do they attack the bees by chewing on a vital organ called the fat body, but they also introduce problematic viruses to the hive – such as deformed wing virus, which does exactly what it says on the tin.
Beekeepers all across the world must treat varroa mites many times a year just to keep their numbers under control. They typically utilise pesticides, which might be harmful to bees and the environment. Pesticide resistance is also developing in the mites, although a new treatment option may be on the horizon.
PhD candidates Zoe Smeele and Rose McGruddy have been looking into this. They've been working with US biotechnology company Greenlight Biosciences to explore how their innovative varroa mite therapy works under the direction of Professor Phil Lester.
The therapy is based on a process known as RNA interference. Researchers discovered an intriguing bio-hack in which they use a natural virus defence mechanism in the cell against one of the mite's essential proteins.
Greenlight Biosciences was able to identify a therapy that reduced mite numbers in field experiments in the United States, but they went to New Zealand researchers for assistance in determining exactly how it works.
Zoe and Rose have been doing mini-hive studies in one of the research labs at Te Herenga Waka Victoria University of Wellington's School of Biological Sciences. Their participants are larval stage bees infested with varroa mites retrieved from hives on the building's roof.
Nurse bees who feed the larvae are given plastic pouches with sugar water and the RNA interference treatment. The scientists discovered that instead of killing the mites, the therapy has a significant impact on their reproduction.
Initial field testing with New Zealand beekeepers showed some promise, but also revealed that there is still much to learn about dosage per bee. A new series of experiments is just getting started, and it will incorporate RFID tagging of bees to track any consequences down to the individual bee level.
Listen to the podcast to get up close and personal with a hive while learning about the stages of bee development. In addition, learn how RNA interference therapy works and why researchers and some beekeepers are excited about its potential.