Will My Bees Develop Natural Resistance if I Don’t Treat or Manage Varroa Mites?

Unfortunately, not controlling Varroa will spread Varroa to your other hives and often all the hives within a few miles of your own bees. Not controlling Varroa, in some manner, is irresponsible as a beekeeper and inhumane to the bees. Just like we would never neglect to treat a pet for an infestation of fleas, mites, or ticks, especially if it could lead to their death, we should practice proper animal husbandry and take care of our bees as well. Breeding bees to become consistently resistant to mites has been the lifetime pursuit of many brilliant beekeepers and scientists, and the great news is that they are getting closer every year! I do think in the next five years we will see some great, commercially available options to largely control Varroa using genetics. 

There are three common outcomes when you don’t treat or intervene, in any way, for Varroa. 

1. Your hive does fine since they didn’t have a very high mite population to begin with or since you hit the lottery in beekeeping and your hives are resistant enough to mites to survive without treatment. This is very rare, but it can happen. If you don’t test to confirm this, the odds are certainly not in your favor that this will be the outcome. I would say this would be the case with only a small percentage of hives in the US unless intentional and careful breeding programs are in place. There are always some beekeepers who say they’ve never treated for mites and their hives do fine. However, that is certainly not the norm. Another noteworthy thing to mention is that, even if your hive survives with higher mite loads, you are spreading mites to all hives, both feral and managed, within a few-mile radius of your own beehive as some bees drift from hive to hive. This has become known as a “mite bomb.” 
2. Your hive dies quickly. This is a common outcome. Mites weaken a hive both through sucking the fat and transferring viruses to adults and developing bees and transmitting viruses. They can quickly or slowly kill hives depending on the mite population and how healthy your hive was to begin with. See “How to Tell if My Hive Was Killed by Varroa Mites.” If the population of mites increases rapidly, a hive can go from a deep box or two full of bees to a few frames of bees, or dead, in weeks. 
3. Your hive is greatly weakened and slowly dies over a period of months. This is the most common outcome. As the mite population steadily grows, the bees' immune systems are increasingly weakened. They contract viruses and other diseases and eventually die. Your hive may look fine for a while, but when it begins to get cold in the winter, they will quickly dwindle and die. Many beekeepers think the hive is fine since the population was healthy over the summer, but as the bees begin to cluster as the weather cools, it becomes more apparent how weakened they are. After a few cold fronts, they die.

Regardless of your stance on treating for Varroa mites or not, as evidenced by these statements, managing Varroa mites is required. There are several options to control mites that don’t always involve chemicals. See “Natural and Chemical Varroa Treatments”

Photo Credit: Rob Synder - Bee Informed Partnership