Scientific research is crucial for understanding why bees are dying and how humans can help them thrive again. The challenge with research, whether it’s about bees or humans, is that living things don’t exist in hermetically sealed environments. Bee health is impacted by a variety of factors that interact with each other in yet undetermined ways.
Nonetheless, we did learn a few things about bees this past year and saw published research that holds promise for additional areas of study and, potentially, solutions. It’s a good time to review the state of bee science.
Let’s explore this research further.
It’s fairly common practice to use managed bees for agriculture and on protected lands – in our country and abroad. In 2019, there were over 2.67 million managed honey bee colonies in the United States, with over five colonies per operation. Honey bee colonies are transported across variable distances and placed on agricultural land to help pollinate crops, including apple trees.
Unfortunately, using managed bees seems to interfere with native bee populations. The negative impacts documented thus far include competing with native pollinators for nearby flora and with other organisms for nesting sites. Basically, they interfere with the local ecosystem.
Minimizing the use of managed honey bees in protected land areas but allowing their use in agricultural situations may be a solution. This would help protect wild bee populations from disease transmission and the aforementioned impacts. It’s not a question of eliminating managed bees entirely or limiting their use to only agriculture, but how to manage the situation more effectively.
In this case, that means better conservation policies for managed honey bees to preserve overall health, whether it’s managed bees or wild bee populations.
If you keep bees, you’ve likely had a run-in with the varroa mite. These small critters can wreak havoc on bee populations, causing larger-scale die-offs. They also spread viruses to the bees causing catastrophic effects like deformed and ineffective wings.
There is research that shows the cell size of the honeycomb impacts how severe varroa mite infestation can be – cells that are 4.9 mm in size seem to have lower incidences of infestation compared to 5.5 mm. When there’s excess space in the honeycomb cells, it’s extra space varroa mites can capitalize on.
There are chemical treatments for varroa mites, like oxalic acid and various pesticides, but mites can and do develop resistance and the problem persists. Plus, the chemicals themselves can have undesirable side effects for the bees, like reduced larvae production. Scientists and beekeepers alike are looking to selective breeding to help.
This whole area of research is rich and fascinating. With tests that look for certain markers for mite resistance in the bee’s antennae to the sequencing of the bee genome, scientists can distinguish particularly hardy bees. What is a hardy bee when it comes to mite infestation?
Some bees exhibit naturally protective behaviors against mites. For example, some bees shake or bite the mites’ legs until they fall off. Additionally, some bees are adept at VSH (varroa sensitive hygiene), which means the bee uses its antennae to tap honeycomb cells, checking for specific chemical markers. When it finds a cell in question, it nibbles a hole in the cell and notifies the worker bees who clean honeycomb cells to come to the area. These worker bees then rid the cell of its contents: varroa mite larvae.
Selective breeding focuses on identifying bees who exhibit these behaviors and using their genetic material to reproduce, creating hardier bees. It’s a bit laborious to do this research. At Purdue University, students examine hundreds of colonies every year. They count fallen mites and their missing legs and using the queens from colonies with the most mite damage to breed for VSH.
Of course, beekeepers can always let natural selection run its course as it does eventually yield hardier bees, but the cost in the meantime can be immense.
We know pesticide use can negatively impact bee health. However, there are a lot of pesticides out there and we just don’t have the studies available to demonstrate which ones and in what combination to guide our course of action.
In one study, bees were given dietary exposure to worst-case concentrations of seven pesticides: amitraz, coumaphos, fluvalinate, chlorpyrifos, imidacloprid, chlorothalonil, and glyphosate. That’s a mouthful. For the bees, too.
Exposure took place over six days and the results showed pesticide exposure altered the expression of detoxifying enzymes. In terms of survival rates, there were across-the-board losses.
The survival rate of larvae exposed to pesticides used for varroa mite infestation – amitraz, coumaphos, and fluvalinate – was the lowest of any of the pesticides. For fluvalinate, 100% of the larva did not make it to the pupal stage. Chlorothalonil, imidacloprid, and chlorpyrifos also saw marked reductions in larval survival rates.
Other variables evaluated in the study included antennae malformation, adult body size, and hypopharyngeal gland cells – all impacted to varying degrees.
Though this was designed to be a worst-case scenario as far as pesticide concentrations go, it can also serve as a warning that pesticides do impact bee health. It would behoove us to pay more attention and reduce overall use if we want bees to thrive.
Did you know bees can count? In the last few years, we saw an influx of studies evaluating the cognitive abilities of bees. Bees can distinguish “left/right”, “above/below”, “same/different”, and “larger/smaller”, for example.
For this particular study, bees used color, blue for addition and yellow for subtraction, to add or subtract an element from a sample. Researchers used appetitive-aversive methods in this case, but there are notable studies that used positive reinforcement to also demonstrate bee learning capabilities. Results showed bees were able to learn and apply numerical cognitions.
As we learn more about bees, we learn more about their complex learning abilities. The application for bee conservation isn’t entirely clear, but the results can at the very least inspire respect for our ladies in yellow and black.
Perhaps respect can spur further action on behalf of the bees.
The Conservation Reserve Program is an exchange program, where farmers receive a rental payment to convert environmentally sensitive land on their property from agricultural production to planting yards that improve environmental quality.
There are now studies about bees and how they interact with this program. We know bee health is linked to foraging activities and the quality of foraging resources. This program provides large swaths of land with high-quality native flora.
A recent study explored biomarkers in pre- and post-winter critical time periods for bee health. The specific biomarker researchers evaluated showed a higher gene expression of vitellogenin, which is a protein that influences regulatory functions. It may help with stress resilience in bee populations.
Bees with hives within foraging distance of CRP lands had higher levels of this biomarker. The study found larger adult bee populations for hives in close proximity of CRP lands as well.
If we take care of our lands, cultivating plant biodiversity, we help take care of our bees.
The more we learn about bees the better positioned we are to help them. But, we don’t have to wait for further research to define our actions. Bees need robust foraging environments. We know pesticides are not great for bee health. We know varroa mites impact bee populations and we need to find creative solutions.
There is a lot that is within our control and choices we can make as beekeepers, as stewards of the environment, as individuals.
If you plant more pollinator-friendly flowers this spring, it’s a low-risk way you can contribute to bee health. You don’t need extensive research to trust it’s the right thing to do. We can refine our approach as more research comes out in the next few years.
The bees depend on it.