Why Are So Many Bees Still Dying?

Posted 11/19/2021 BY Bruce Rutter

bees festooning

Perhaps it’s the influence of Hollywood, where civilization is always rescued at the last minute by a brilliant scientist, or a dying child is saved by a doctor who wouldn’t give up until she’d found a cure, because we all seem to hope for silver bullets that will solve our most perplexing problems. “Bee colonies are complex, adaptive systems—they’ve evolved to deal with a host of inter-related factors including climate change, weather, food supply, competition and pathogens.” Says our Staff Scientist Emily O’Neil. “No single solution can address all of these; instead, we expect to find, over time, a number of inter-related solutions that will work together to significantly improve bee survival and health.” At The Best Bees Company, we never give up hope for finding solutions to the many issues facing bees, but as scientists, we know there are no silver bullets waiting to save bees.

“No single solution can address all of these; instead, we expect to find, over time, a number of inter-related solutions that will work together to significantly improve bee survival and health.”

-Emily O’Neil, Staff Scientist at The Best Bees Company

There’s no question that bees are in trouble. While the threat of colony collapse disorder has abated, more than 40% of all bee colonies in the U.S. still die each year. Extreme weather conditions can push that to 50, 60, even 70% in some areas. A terrible problem for beekeepers and farmers, but why should everyone else care about bee loss? It’s quite simple: as pollinators, bees are essential to our food supply and the health of the environment. Without bees, we’d lose the majority of fruits and vegetables we eat.  Our ecosystems—already under great stress—would further degrade, and with environmental loss would come greater pollution and faster global warming. Our personal well-being, and the well-being of the businesses and organizations we own, manage or work for, are all tied to the health and survival of bees.

At Best Bees, we’ve been caring for and studying bees for more than 10 years. Working with more than 1,000 hives in 15 metropolitan areas, we’ve amassed the largest database on bee health in North America. While the condition of bees we keep has steadily improved, we believe there is much more we can do if we systematically analyze data on bee health and morbidity.

A new, comprehensive study of bee health.


Beginning this January we’ll begin a deep-dive into data we’ve collected from 25 strong and 25 weak hives in five different areas around the country (Boston, Ithaca NY, New York City, San Francisco and Seattle). In a 31-step process in both the field and the lab, we’ll be looking for what leads some hives to thrive, and what causes others to die. The study will follow an iterative process of hypothesis, investigation, analysis, and conclusion, with the expectation that our learning will lead to interventions that combine and build, over time, to become ever-more effective. 

The first step in this research project will be to look at the most common factors that apply to bee colonies, regardless of location: 1) nutrition; 2) bacterial and fungal diseases; 3) virus loads; 4) varroa mites; 5) Nosema. Future studies may expand this to include pesticide exposure and location.


To survive, honeybees require a diet that includes a mix of nutrients that include: carbohydrates, which they get from sugars in nectar or honey; amino acids, derived from the proteins in pollen; lipids, such as fatty acids & sterols; plus vitamins, minerals, salt and water. To thrive, these nutrients must be present in the right ratio. There is a growing body of evidence that poor nutrition can be a major player in affecting honeybee health. A study by bee scientists Eischen and Graham in 2008 showed that well-nourished honey bees are less susceptible to Nosema ceranae, a parasitic fungus that can severely weaken, even kill bee colonies.  In our study, we’ll be looking at the number of honey and bee bread (pollen) frames in hives to gain a basic understanding of how much food they’ve been able to forage and store. Then we’ll test the DNA of honey from these hives to see which flowers were used to make the honey, which will give us an idea of whether they are receiving the correct balance of essential nutrients. This learning could lead to solutions such as supplemental feeding, and the cultivation of plants nearby to yield a reliable mix of nutrients year-round.

For more information on honeybee nutrition, visit: https://www.agrifutures.com.au/wp-content/uploads/publications/05-054.pdf

Bacterial and fungal diseases

Bee colonies are susceptible to two bacterial infections—American and European Foulbrood—and a fungal infection known as Chalkbrood. All three are serious threats to bee colonies.  While there is no chemical treatment for Chalkbrood, good bee breeding and hive management can prevent its spread.  Both forms of Foulbrood are highly contagious, and so require destruction of infected colonies. Of the two, American foulbrood is the most dangerous, and can easily be spread by beekeepers using tools infected by the bacterium’s spores. We hope that we’ll learn how to detect infection early and be able to quickly contain it and prevent its spread. Keen observation, rapid response and superior hygiene may prove the best solutions to these infections.

For more information on bacterial and fungal diseases, visit: https://bees.caes.uga.edu/bees-beekeeping-pollination/honey-bee-disorders/honey-bee-disorders-fungal-diseases.html

Virus levels

Honeybees are susceptible to 19 different viruses that can have a range of impacts from asymptomatic infection to the destruction of entire hives. While most of these infections aren’t fatal on their own, high virus loads can inhibit bees’ immune systems, leaving them vulnerable to other stressors, which can eventually kill them. Unfortunately, there are no specific treatments for any of the viruses infecting bee hives. Current treatment includes minimizing the chances of viral transmission and minimizing other stressors.

To learn more about viral infections and their impact on honeybees, visit this site: https://extension.psu.edu/viruses-in-honey-bees

Varroa mites

Varroa mites (Varroa destructor) are the foremost pest affecting honeybees worldwide, limiting productivity, transmitting deadly viruses, suppressing bee immune systems and shortening bees’ lives. If mite infestations are left unchecked, they can kill entire hives; without intervention, colonies typically die within six months to two years. While we’re always on the lookout for varroa mites during every beekeeping visit, varroa infections tend to peak in late summer and early fall, and so we will be extra vigilant in observing and treating infected hives during August, September and October. Our most common treatment is with miticides. Going forward we will be looking at promising alternatives, such as using new strains of bee known as “Varroa Sensitive Hygiene Bees” that detect and kill mites in their hives.

To learn more about solutions for varroa mite infestation, visit this site: https://extension.psu.edu/methods-to-control-varroa-mites-an-integrated-pest-management-app

Varroa mites, in a wax cell and on the back of a mature honeybee.


Nosema, a fungal disease, is one of the most prevalent infections in honeybees worldwide. Indications of Nosema infection are colonies that are low in population, slow to build up, and slow to produce brood and honey. Nosema infections affect the overall health of colonies and can lead to colony death. Promising treatments include choosing an apiary site with good drainage and sun during winter, as low moisture and good ventilation can help discourage Nosema from proliferating.

For more information on Nosema and its treatment, visit https://scientificbeekeeping.com/the-nosema-problem-part-6-treatment/


Apply & share learning


Through a rigorous scientific approach, we’ve learned a lot about bee health in the 10+ years we’ve been working with bees, and so are confident that this study will yield much new learning and best practices.  Given the wide scale of our data and the longevity of our study, we believe we’re in a unique position to improve the health of the bees we keep and share this learning with partners and beekeepers around the world. 

We hope to release initial findings from this study in late winter, once we’ve been able to complete our deep-dive into the data we are collecting.  Stay tuned!

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