It isn’t just pesticides and the destruction of habitat that’s making the world’s honeybees very unhappy. One of the biggest threats is Varroa destructor, a disease-spreading parasite that is just as villainous as its name suggests.
Through a chance discovery, German scientists from the University of Hohenheim have stumbled on a new method of wiping out this parasitic pest without harming the bees.
The US Department of Agriculture views the Varroa mite as “the major factor underlying colony loss in the US and other countries.” After infiltrating a colony, the mites begin to feed on the bodily fluids of honeybees and their larvae. Along with weakening the bees, the mites also spread viruses, such as deformed wing virus, and can quickly wipe out entire colonies.
As reported in a recent study published in the journal Scientific Reports, scientists have now discovered that feeding honeybees just 25 millimoles of a water-soluble salt called lithium chloride (LiCl) can kill 90 to 100 percent of the mites within days.
“Lithium chloride can be used to feed bees in sugar water. In our experiments, even small amounts of saline solution were enough to kill the mites sitting on the bees within a few days – without side effects for the bees,” Dr Peter Rosenkranz, head of the State Institute of Apiculture, explained in a statement.
Currently, beekeepers treat infested beehives with aggressive organic acids or chemically derived miticides. However, mites can quickly gain resistance and these substances can also leave potentially harmful residues. Furthermore, no new active compounds against V. destructor have been registered in the past 25 years.
Previous to this latest breakthrough, scientists were looking to tackle Varroa infestations using a technique known as RNA interference (or RNAi), which switches off their vital parasite genes. This experiment appeared to be a success, however, the control mites also died. The researchers wondered whether this effect was due to the lithium chloride used in the production of the RNA. Later experiments proved this to be the case.
This newly developed technique of using lithium chloride is low cost, easy to manufacture, won’t accumulate in beeswax, and has a relatively low toxicity to mammals. So far, so good, but it’s perhaps premature to say whether this discovery could be the savior of honeybees. However, with few other options on the horizon, scientists are already in talks with companies in hopes of getting this solution off the ground and into the market.