VARROA DESTRUCTOR THE LIFE CYCLE OF A KILLER
By Chari Elam
Simply put the Varroa destructor (actual genus name) is an external parasitic mite that attacks and feeds on our Western honeybees Apis mellifera. The Varroa mite is considered the number-one cause of death in honeybees worldwide. That’s a pretty strong statement isn’t it? Ongoing tracking reports over the past decade show colony losses averaging over 40% each year. That’s nearly half of all honeybee colonies lost due to this one factor alone! Between the colony loss itself and the cost of trying to prevent losses Varroa mites cost beekeepers millions of dollars year after year across the globe. That in itself should be enough to get all of our attention!
When Varroa mites were discovered in the United States (1987) beekeepers didn’t have the treatment arsenal we have now much less the science to back it up. Fast forward 37 years and we now have good tools to help us manage these beasts the size of small ticks. These tools include treatment methods that accommodate most any preference a beekeeper may have—mechanical organic or chemical. All of these methods come with good solid research and data to back them up along with educational resources to help an entire beekeeping community win the battle against the Varroa mite.
Live Cycle of the Varroa Mite
Simply stated honeybees are the only host for this parasitic mite. They travel (spread) from colony to colony by jumping from bee to bee while they’re foraging or from drones that tend to drift to other hives. Once in the hive a mature female mite jumps into a cell just prior to its being capped (day nine). That female mite then starts feeding on the developing bee. Within three days she lays her first egg which is always a male. Subsequently the female Varroa mite will lay another egg (female) every thirty hours which mates with her brother mite until the honeybee emerges ten days later. At that point the fertilized mites emerge only to repeat the cycle again and again.
While this Varroa mite is inside the cell and feeding on the developing bee it is transmitting several different viruses. The viruses are then spread throughout the young bees causing a domino effect of sick bees. A multitude of problems arise from these sick bees. Just to name a few:
- Poor nursing abilities
- Poor foraging ability
- Shorter life span
- Deformed wing virus preventing a bee from flying at all
- Parasitic mite syndrome: signs include rapid decline of the adult population increased supersedure of the queen and lack of eggs and developing larvae
Follow this link to learn more about supersedure cells
Killing a Bug on a Bug
The first method of control of Varroa destructor is testing. As we enter population increase—yes in January—it is imperative that we develop a testing schedule and commit to abiding by it religiously. Whether that be four times a year or once a month stick to it. In the following months we will dig deeper into how to treat and which treatment options to use. In the meantime get familiar with the methods of testing by watching these videos and reading as much as you can find. The Honey Bee Health Coalition is a fantastic resource for all things Varroa—from testing to treating and even a decision tool to aid in determining what treatments to buy and when.
Regardless of where you fall in your views of how to treat an infestation of Varroa mites beekeepers have a responsibility to learn how to test and how to treat accordingly. Visit our Bee Help & Questions page for more resources on those very topics!