Ridding bee colonies of Varroa mites is key, but keepers must take a holistic approach to maintain thriving hives.
With colony collapse disorder (CCD) decimating significant numbers of hives every year, research scientists and beekeepers continue their search for solutions. Honey bee colonies face a lot of different predators, from natural – bears and skunks, to man-made – industrial farms and power line companies that incautiously apply pesticides, all of which threaten healthy bees and hives.
Beekeeping supports agriculture in inestimable ways by supplying honey and enabling the large-scale pollination of high-value crops, especially fruit and vine crops. Almonds alone, require approximately two million bee colonies for crops to flourish in the U.S.
One of the most prevalent challenges to healthy bees, however, comes from the miniscule Varroa mite. Appropriately named varroa destructor, this flat, button-shaped parasitic mite of less than 2 mm in length and width attaches itself to the body of Asian honey bees (Apis cerana) and European honey bees (Apis mellifera). Varroa mites can cause honey bee colonies to collapse by feeding on the fat reserves of the adults and larvae. They also spread more than 20 types of deadly ribonucleic acid (RNA) viruses.
Fighting The Most Deadly Virus That Destroys Bee Wings
Perhaps the most deadly virus affecting bee colonies is the deformed wing virus (DFW). Experts claim DFW is one of the largest contributors to CCD. Affected hosts develop shrunken and misshapen bee wings that prevent them from flying. This significantly reduces the number of plants they pollinate. It also damages their immune systems, cutting their life spans in half.
Frantic to rid their hives of these time bombs, beekeepers have employed everything from traps and targeted pesticides to destroy the Varroa mite. In the October 4, 2018 issue of Wired, an article discussed the innovative research of several scientists who are now studying a mushroom extract they believe might save bees from the deformed wing virus.
Led by prominent mycologist Paul E. Stamets, the study initially appeared in Nature Scientific Reports. The two mushrooms studied belong to an order of fungi known as polypores. Numerous studies have demonstrated that extracts from these mushrooms contain powerful antiviral properties against dangerous infections such as swine flu, HIV, and poxviruses.
Stamets, the author of Growing Gourmet and Medicinal Mushrooms, has long proposed that bees benefit from sipping droplets of liquid oozing from mushroom mycelium. Typically located underneath the mushroom head, that part of the plant is the fuzzy white network of filaments through which fungi absorb nutrients.
Initial studies indicate there may be cause for optimism regarding use of the extract to combat Varroa mite devastation. However, many questions still need to be answered. For example, does the extract bolster the bee’s immune system? Or does it inhibit the virus directly? Or does it possibly impact the way it replicates within the bees?
Stamets acknowledges that much more research needs to be completed. “We’re doing tests right now in several hundred more beehives,” he says. “We’re ramping up.”
The Solutions To Healthy, Thriving Bee Colonies Are Complex
Denzil St. Clair, owner, Queen Right Colonies in Spencer, Ohio, near Lorain, has been a beekeeper for 50 years and boasts an extremely low hive loss rate. He prefers focusing on raising healthy bees and going after the source rather than taking on one virus at a time.
“Even if you cure deformed wing virus, we still have 21 other viruses or more to worry about, and the Varroa mite is the cause,” he says. “We need to find a solution to the entire problem of what is killing colonies.”
Currently, there are chemicals and other approaches beekeepers use to control the pesky and prevalent parasites. For St. Clair, one of the challenges is sorting through the myriad options to identify the most effective. Ohio, for example, has more than 40 beekeeping organizations statewide that offer training programs and as many different techniques.
“We need to provide beekeepers with a simplified version of Varroa mite control,” says the seasoned beekeeper, as he does with his training courses. “Then they can branch off and find the products and approaches that work best for their colonies.”
Challenges With Chemical Treatments
Another challenge lies in the fact that typical spring and fall treatments don’t always work, and some mites have developed resistance. Treatments can also backfire, as one amateur beekeeper, BartJan Fernhout in Boxmeer, the Netherlands, learned. His story is detailed in an article in Science about beekeepers seeking to toughen their bees to resist the Varroa mites.
In order to fight mites, Fernhout applied a chemical which ended up stopping his queen bees from laying eggs. The instinctive hive response of the worker bees is to kill those queens and begin to raise new ones. Some other remedies needed to be found. Recognizing that problems present opportunities, the entrepreneurial Fernhout quit his job and launched Arista Bee Research. Arista Bee Research is a nonprofit with a mission to breed honey bees equipped to resist Varroa mites on their own.
Researchers have found some bees are able to combat the parasites through meticulous grooming and removal of any mite-infested larvae. Still, efforts to identify which bees have those capabilities have proven to be frustratingly tedious. Researchers and breeders, the article explains, have also created bees that require fewer pesticides, yet “even those colonies can be overrun by mites.” According to one researcher cited in the piece, progress has been “less than significant.”
Some Promising But Still Distant Discoveries Ahead
Fortunately, scientists, as part of a global movement to ensure honey bee health, are working diligently to discover ways to enhance Varroa mite resistance in the industrious insects. Doing so would ensure honey bee health and thriving hives.
Some of the research is even performed at the molecular and genetic levels. For example, the Science article referenced above discusses a new protein-based test that would allow beekeepers to submit a few dozen bee antennae to a laboratory for testing. The test would reveal whether or not their insects possess mite-detecting capabilities.
Additionally, scientists are researching methods to sequence the genomes of sizable numbers of bees. Their ultimate goal is to create an affordable, simple, effective way to identify bees that carry genes for protective behaviors. Fernhout considers this type of test “almost the Holy Grail” of anti-Varroa research.
Ensuring Honey Bee Health Requires A Holistic Approach
Treating colonies to destroy the Varroa mites and reduce or eliminate the viruses they spread is absolutely essential. But beekeepers have other best practices to keep bee immune systems strong and their hives healthy.
Ana Locci, Ph.D., director of Squire Valleevue and Valley Ridge Farms in Chagrin Falls, Ohio just east of Cleveland, recommends the following steps for beekeepers:
1. Keep the hives closed as much as possible. Every time you open the hive it disturbs the bees and forces them to readjust the hive. Preferably only open the hive once in the spring and once in the fall.
2. Keep an eye on the bees. Check the hives regularly, but watch their behavior from the outside of the hive. If they are flying or walking irregularly, then that may indicate a virus. Or, if there are large numbers flying outside the hive, it may indicate that they have run out of room and require additional frames or boxes of frames.
3. Keep up with current literature and maintain a good relationship with local bee inspectors and associations.
4. Do not use chemicals for lawn care, weed killing, or pesticides. Communicate with neighbors – within about a five-mile radius of the colonies – to see if they use any chemicals and, if possible, ask them to use only organic products.
5. Make sure there are plenty of flowers or flowering trees near the hives throughout the spring and summer and within that five-mile range that they usually fly.
“Raising healthy bees is not an easy job, and you must constantly be learning,” says Locci, who also serves as an adjunct assistant professor of biology at Case Western Reserve University, which owns the farm. “But there’s nothing more rewarding than to see a new hive with honey or your healthy hive just doing well.”