A parasitic mite known as Varroa destructor has spread to most areas of the world within a short time period, and it is now difficult to find a “varroa-free” honey bee colony.
Honey bees perform the vital service of pollinating certain important food crops. Therefore, the more we learn about the challenges beekeepers face to keep their honey bee colonies healthy, the more compelled we are to help them overcome these challenges.
Honey bee health is a complex issue that is affected by multiple stressors
, including introduced pests and parasites
, microbial diseases
, inadequate forage and nutrition, bee management practices, lack of selection for better performing local genetic stock, queen mating issues, and occasional improper use of crop and bee protection products.
However, when pushed to name one significant enemy that undoubtedly affects the welfare of bees, bee experts around the world agree that the Varroa mite poses the greatest threat to the western honey bee.
The Varroa mite in detail
The Varroa mite is an arachnid that measures approximately 1.6 millimeters long. It is an external parasite that attacks both honey bee pupae and adults, weakening them and allowing pathways for diseases that can spread throughout the colony and can be passed on to other colonies by drifting, robbing or absconding worker bees.
Varroa mites feed by sucking honey bee blood (hemolymph). By feeding on a honey bee, Varroa can also transmit deadly viruses. One of the viruses most often transmitted causes deformed wings. Varroa feeding also weakens honey bees and shortens their life span, making it difficult for colonies to survive the overwintering process. Once a honey bee colony is infested with Varroa mites, the parasites spread very quickly, and if left unmanaged, an infestation can become so serious that it will wipe out a honey bee colony within a matter of months.
National Geographic photographer Anand Varma worked with a bee lab at the University of California, Davis (U.C. Davis) to figure out how to film the first 21 days of a bee’s life. In his video of the pupation process, viewers can actually see Varroa mites running around in the cells with the honey bee pupae.
Tackling Varroa mites and improving bee health
Varroa mites have proven difficult for beekeepers to control, and researchers continue to look for new mite treatment and management options to stop these destructive parasites, including varroacides and selective breeding to produce bees with better resistance to mites.
Helping bees battle the Varroa mite and other stressors through the use of “Smart Hives” and stock improvement programs is important to improving overall bee health. To that end, Bayer has launched Healthy Hives 2020, a major initiative focused on finding tangible solutions to improve the health of honey bee colonies in the United States by the year 2020.