Updated: Aug 20, 2021
01/26/2021- The Apis Mellifera otherwise know as the western honey bee has been struggling to survive against the Varroa Destructor mite, and beekeepers have been trying to help their colonies defeat or manage it since the 1980's in their beehives.
Hygienic Honey Bees
The western beehive has evolved over thousands of years to be the creature we see today and though it has evolved to handle all sorts of pests and climate challenges, the mite is a bit unique. Honey bees in Asia have developed/ evolved to manage the mite and has done so, for hundreds if not thousands of years.
The Varroa Mite has Landed
It wasn't until the 1980's, so the industry estimates when the Varroa Destructor, which was only home to Asia as far as we know, spread west. They honey bees didn't have the time that evolution normally grants them due to the ease of transportation nowadays. This has led to major efforts by beekeepers, scientists, researchers, and the like to come up with a solution to help the Apis Mellifera through management practices, synthetic drug treatments, organic treatments, and others.
Short Game vs. the Long Game
Beekeepers have been progressively seeing large losses due to colony collapse disorder (CCD), which is a complicated discussion within itself. However it is mostly adopted that the Varroa mite is the largest contributor to CCD and annual bee losses of ~45%. Losses like this have been tracked voluntarily through organizations like the Bee Informed Organization, and the annual losses are not getting any better over the last few years.
Short Game- Treat/ Manage
The mostly adopted short term game plan has been to treat the colonies, which has been creating some problems with drug resistance to some of the treatments. The treatments are pesticides meant to kill an insect on an another insect, so precision is vital in ensuring both insects are not killed. Some of the arguments against treating with chemicals whether organic or synthetic, are-
is that those chemicals likely end up in the honey
the treatments are strengthening the mites resistance (Amitraz is an example)
treatments are weakening the genome of the bee, making them chemical dependent
The short game has been all about treatments of the bees, with some successes and others that have been total failures. Some of the treatments have provided the mites with resistance to the chemicals that are made to defeat them. Currently mites have developed a resistance to Amitraz, which is the main pesticide in Apivar® and Apitraz®, and is no longer recommended for treating bee colonies.
Treatments are widely adopted among beekeepers currently and are critical to commercial beekeepers. As an example provided in Phys.org-
In the early 1990s, Daniel Weaver, a bee breeder in Navasota, Texas, let the mite run wild in 1000 of his colonies. Just nine survived the first year, and from these he bred mite-resistant bees. "It was a painfully expensive experience," he recalls, and costly enough to put many beekeepers out of business. Such natural culling could also mean losing valuable bee strains produced by decades of breeding.
As a result, many beekeepers treat their hives with pesticides. Others add in or substitute nonchemical methods, although they are more work and can pose trade-offs. For example, mimicking swarming by transferring a queen and some workers to a new hive means a smaller colony and less honey for a while.
Another way beekeepers have been managing against varroa, is to provide brood breaks through timely splits. The mites reproduce within the cells of brood and need capped brood to continue their growth. Timely splits can prevent and greatly reduce mite infestation by transferring queens to new equipment as well as placing brood in queen less hives.
By transferring the queen to new equipment, the bees will need to take time building up new frames which provides several day or weeks of brood less hives, preventing the mites from mating and infesting the new split.
Brood in Queen Less Hive-
By removing the queen, the hive will take several of the eggs and produce new queens. This gives the brood break for 16 days, plus the days or weeks for mating. So by doing this the hive gets a new brood break for approximately 18-25 Days.
Long Game- Hygienic Bees
The mite originated from Asian honey bees (Apis cerana), which had a natural hygienic behavior, something the western/ European (Apis Mellifera) had not possessed, resulting in large colony losses. Time will provide the solution through natural selection if we as beekeepers allow. Unfortunately the average beekeeper cannot perform effective bee breeding without an all-in or all-out approach.
What I mean is, through treating you are not allowing the hygienic bees to rise and survive as the weak survive and stay within the gene pool and you are relying on the luck that the non-hygienic genes mix with other characteristics of value, such as honey bound, gentle, etc. Even bee sellers that advertise hygienic are relying on this such luck as well and label them hygienic based on results of "tests" of comb cleaning or bee analysis from a lab or similar.
There are many successful chemical free treatment commercial and backyard beekeepers, but most of them still rely on management practices to assist the bees in fighting the mites. The hygienic bee is the solution to not requiring management practices in regards to the Varroa Destructor mite. Some of the arguments against NOT treating with chemicals, are-
Your colonies will result in massive losses
It is cruel to just let the bees die (You could argue chemicals are equally as cruel)
Other breed characteristics could be lost that took years to develop
Light at the End of the Tunnel
Researchers have analyzed and compared non-infested and infested brood cells. They were able to identify 6 different molecules in the infested cells that had never been identified in honey bees. These molecules where then synthesized and carried out by the researchers in several behavioral tests in order to determine if the mixture of these molecules could trigger hygienic behavior in the bees.
The team of researchers began by comparing the bees behavior faced with parasitized cells with those that had been injected with a compound. In both scenarios, researchers observed positive responses from the bees cleaning out the cells. They also studied the behavior of different colonies with differing levels of hygienic behavior in prompts to varroa. The colonies with the highest levels of hygiene, the bees single out the sick or dead brood cells and clean them out. This was not systematically done in the colonies with moderate to low hygienic characteristics. These results showed the most hygienic colonies have a strong reaction towards brood cells containing the compounds.
Within each colony, different bees have different tasks and functions and only some of them exhibit the hygienic behavior. In a last test, the researchers compared the response of hygienic and non-hygienic bees to the mixture of molecules. The results- All bees are able to integrate the information into the central level of the brain and, consequently, adopt a hygienic behavior cleaning the contaminated cells.
The discovery of the compound of molecules specific to Varroa destructor-infested brood cells opens up new perspectives for beekeepers in the fight against this pest. This would enable them to identify and select the colonies that might be more resistant to the parasite by studying their reaction to the compound of molecules. INRAE and the University of Otago have filed a patent on these molecules and their applications. Research is currently underway to develop reliable tests that can be used by beekeepers in order to select Varroa destructor-resistant colonies.
Resent Article on ScienceMag.org
"Although researchers and breeders have created bees that require fewer pesticides, even these colonies can be overrun by mites—and very few lines can yet survive without any treatment. "There is progress, but not very significant," says Benjamin Dainat, a bee researcher and breeder at the Swiss Bee Research Centre in Bern.
New molecular tools promise to accelerate those efforts. A new protein-based test, for example, would allow beekeepers to simply send a laboratory a few dozen antennae, plucked from their bees, to learn whether the insects have mite-detecting powers. Other scientists are sequencing the genomes of huge numbers of bees, hoping to create a relatively cheap and easy way to identify bees that carry genes for the protective behaviors. Such a test "is almost the Holy Grail" of anti-Varroa research, Fernhout says.
A success would help secure the future of the multibillion-dollar honey bee industry, which supplies honey and enables the largescale pollination of high-value crops, such as almonds. If breeders can spread resistant bees, then "the long term is looking good" for controlling the mite and stemming the bee die-offs, says John Harbo, a retired biologist and bee breeder in Baton Rouge."
To manage or not, is a complicated topic that will result furious debate over which is correct, and I am not one to say one is better over the other, but I do lean on the treatment-free side of things, while breeding hygienic bees and managing with splits. There has been great movement on the bee breeding and testing to help swing the pendulum in the bees favor, but a lot of work is in front of the beekeepers and bees.