American honeybees just can't get a break

August 14, 2019, 1:30 p.m.
honeybee hive entrance
Photo: Emily Skeels/Shutterstock

American beekeepers have spent decades struggling with colony collapse disorder (CCD), which causes bees to mysteriously abandon their hives. CCD has raised concerns not just for beekeepers, but for farmers of all stripes — plus anyone who eats their crops. U.S. honeybees pollinate about $15 billion worth of crops per year, which provide a quarter of all food eaten nationwide.

It comes as unwelcome news, then, that we're not only still losing lots of honeybees, but we're also losing a key source of data on the bees' well-being. In July, the U.S. Department of Agriculture (USDA) announced it would suspend data collection for its annual survey of the country's managed honeybee population. The survey was launched by the Obama administration in 2015.

"The decision to suspend data collection was not made lightly but was necessary given available fiscal and program resources," the USDA said in a statement, although as the Sacramento Bee reports, officials have not revealed how much the survey costs.

The USDA stopped collecting data for the survey in July, but it still released its last set of results this month, which include data up until April 1. Those results showed little change nationally from a year earlier, but there were bigger drops in some important agricultural states like California. (And, for a broader context, there are now somewhere between 2 million and 3 million managed honeybee hives across the country, down from about 6 million in the 1940s, according to the USDA.)

This follows news, released in June by the Bee Informed Partnership, that 37.7% of U.S. managed honeybee colonies were lost in the winter of 2018-2019, the country's worst winter for honeybees in at least 13 years. That's an ongoing trend, according to the USDA, which notes winter losses have been "unsustainably high" over the past eight years, ranging from 22% to 36% nationally.

Backyard beekeepers lost the most colonies (39.8%) in the winter of 2018-2019, compared with sideline (36.5%) and commercial (37.5%) beekeepers. Backyard, sideline and commercial beekeepers are defined as those managing 50 or fewer colonies, 51 to 500 colonies, and 501 or more colonies, respectively.

The effects of CCD have always varied from year to year — including a dramatic improvement in 2017 — so the broader significance of this shift remains hazy. Plus, drops in CCD are at least partly due to beekeepers' practice of splitting hives. This is a normal practice that mimics how a hive naturally creates new colonies, but it also weakens the original hive in the short-term, and may not be sustainable over time unless life starts getting easier for bees in general.

Mite and main

Varroa mite on honeybee A varroa mite on a honeybee host, captured by a scanning electron microscope. (Photo: USDA [public domain]/Wikimedia Commons)

The causes of CCD are still hazy more than a decade after its 2006 debut, but research points to a variety of triggers for recent bee declines, including varroa mites — invasive parasites that are wreaking havoc with hives across the country.

Varroa mites are native to Asia, and were first found on U.S. soil in 1987. Aside from killing bees directly, the parasitic mites have a mosquito-like knack for spreading infectious diseases through a hive. The USDA lists them as the No. 1 stressor for all beekeeping operations with at least five colonies, and they were reported in 45% of U.S. commercial colonies between January and March of 2019. That's up from 40% during the same period in 2018, and while it's lower than some recent counts, the rate fluctuates during the year, sometimes rising above 50%. That alarms many bee experts like May Berenbaum, head of the entomology department at University of Illinois Urbana-Champaign.

"[I]t's staggering that half of America's bees have mites," Berenbaum told Bloomberg News in 2017. "Colony collapse disorder has been vastly overshadowed by diseases, recognizable parasites and diagnosable physiological problems."

What else is bugging bees

bee pollinating lemon flower Research suggests residue from the pesticide imidacloprid can be high in pollen and nectar of citrus plants, like this lemon tree. (Photo: Larisa Blinova/Shutterstock)

Varroa mites are still just one of many problems facing U.S. honeybees. While they plagued 45% of colonies in the first quarter of 2019, for example, about 15% of all colonies were stressed by other parasites, like tracheal mites, hive beetles and wax moths. Roughly 7% were stressed by diseases like deformed wing virus, while more than 9% battled problems like bad weather and insufficient foraging. Pesticides, meanwhile, reportedly stressed 13% of honeybee colonies during the same period.

Insecticides are widely sprayed to thwart crop pests, but research has shown broad-spectrum toxins can endanger foraging bees, too — particularly a class known as neonicotinoids. And once a colony loses enough adult bees, it can suffer a downward spiral caused by young bees trying to pick up the slack before they're ready, essentially growing up too fast.

These problems aren't unique to managed bees, either. Wild bumblebees are also in decline, possibly even catching diseases from domesticated bees, although lack of visibility means their woes tend to get less human attention. And while much of the focus has been on neonicotinoids, other pesticides pose sub-lethal threats that still imperil bees. A 2014 study found pyrethroids can stunt the growth of young bumblebees, resulting in smaller workers that may be less effective foragers.

In fact, beyond the plight of honeybees, North America's bee biodiversity is in serious danger. About half of bee species native to the U.S. Midwest have vanished from their historic ranges in the past century, and more than a quarter of all North American bumblebees face some degree of extinction risk. And this is part of a broader trend — according to the U.N., 40% of all invertebrate pollinators are on a path toward extinction, including bees as well as beetles, butterflies and wasps.

How to help bees

purple coneflowers in urban garden Purple coneflowers, like these at an urban rain garden in Minnesota, can be a big boost for native pollinators. (Photo: U.S. Fish and Wildlife Service [CC BY 2.0]/Flickr)

Bees need all the help they can get, from domesticated honeybees to their many wild cousins. Most Americans might not be able to protect commercial beehives from mites or viruses, but there are still small things almost anyone can do to benefit bees.

Avoiding outdoor insecticides is one option, especially near flowers where bees might forage. And nurturing native plants could be a huge boon for local bees, whether it's a 1,000-acre prairie or a patch of meadow in your yard. For help planning a pollinator garden, here's a list of plants that support bees, plus more tips for repaying the pollinators who keep our habitats buzzing.

Editor's note: This story has been updated since it was published in August 2017.