Beekeepers across the United States lost 44 percent of their honey bee colonies during the year spanning April 2015 to April 2016, according to the latest preliminary results of an annual nationwide survey. Rates of both winter loss and summer loss—and consequently, total annual losses—worsened compared with last year. This marks the second consecutive survey year that summer loss rates rivaled winter loss rates.
The survey, which asks both commercial and small-scale beekeepers to track the health and survival rates of their honey bee colonies, is conducted each year by the Bee Informed Partnership in collaboration with the Apiary Inspectors of America, with funding from the U.S. Department of Agriculture (USDA). Survey results for this year and all previous years are publicly available on the Bee Informed website.
“We’re now in the second year of high rates of summer loss, which is cause for serious concern,” said Dennis vanEngelsdorp, an assistant professor of entomology at the University of Maryland and project director for the Bee Informed Partnership. “Some winter losses are normal and expected. But the fact that beekeepers are losing bees in the summer, when bees should be at their healthiest, is quite alarming.”
Beekeepers who responded to the survey lost a total of 44.1 percent of their colonies over the course of the year. This marks an increase of 3.5 percent over the previous study year (2014-15), when loss rates were found to be 40.6 percent. Winter loss rates increased from 22.3 percent in the previous winter to 28.1 percent this past winter, while summer loss rates increased from 25.3 percent to 28.1 percent.
The researchers note that many factors are contributing to colony losses. A clear culprit is the varroa mite, a lethal parasite that can easily spread between colonies. Pesticides and malnutrition caused by changing land use patterns are also likely taking a toll, especially among commercial beekeepers.
A recent study, published online in the journal Apidologie on April 20, 2016, provided the first multi-year assessment of honey bee parasites and disease in both commercial and backyard beekeeping operations. Among other findings (summarized in a recent University of Maryland press release), that study found that the varroa mite is far more abundant than previous estimates indicate and is closely linked to several damaging viruses.
Varroa is a particularly challenging problem among backyard beekeepers (defined as those who manage fewer than 50 colonies).
“Many backyard beekeepers don’t have any varroa control strategies in place. We think this results in colonies collapsing and spreading mites to neighboring colonies that are otherwise well-managed for mites,” said Nathalie Steinhauer, a graduate student in the UMD Department of Entomology who leads the data collection efforts for the annual survey. “We are seeing more evidence to suggest that good beekeepers who take the right steps to control mites are losing colonies in this way, through no fault of their own.”
This is the tenth year of the winter loss survey, and the sixth year to include summer and annual losses in addition to winter loss data. More than 5,700 beekeepers from 48 states responded to this year’s survey. All told, these beekeepers are responsible for about 15 percent of the nation’s estimated 2.66 million managed honey bee colonies.
The survey is part of a larger research effort to understand why honey bee colonies are in such poor health, and what can be done to manage the situation. Some crops, such as almonds, depend entirely on honey bees for pollination. Estimates of the total economic value of honey bee pollination services range between $10 billion and $15 billion annually.
“The high rate of loss over the entire year means that beekeepers are working overtime to constantly replace their losses,” said Jeffery Pettis, a senior entomologist at the USDA and a co-coordinator of the survey. “These losses cost the beekeeper time and money. More importantly, the industry needs these bees to meet the growing demand for pollination services. We urgently need solutions to slow the rate of both winter and summer colony losses.”
This survey was conducted by the Bee Informed Partnership, which receives a majority of its funding from the National Institute of Food and Agriculture of the U.S. Department of Agriculture (USDA) (Award No. 2011-67007-20017). The content of this article does not necessarily reflect the views of the USDA.
A summary of the 2015-2016 survey results is available upon request prior to May 10, 2016; thereafter the results will be added to previous years’ results publicly available on the Bee Informed Partnership’s website.
Call it “The Buzzing Dead.” Infestations of what scientists have dubbed “zombie bees” have spread across both the West and East coasts in recent years.
The honeybee hordes, while not actually undead, are the unwilling hosts to a parasite infection that researchers think drives the drones to act erratically, or “zombielike,” in the moments before they die.
To better understand the parasitized swarms, John Hafernik, an entomologist at San Francisco State University has recruited people countrywide to join his hunt.
“The big question for us was, ‘Is this a San Francisco thing?’ Or something that is taking place all over the country that has not been noticed by biologists before,” he said.
After further exploration across San Francisco Bay, he and his colleagues found several bees that were also behaving strangely. They would fly from their hives at night, which was something bees would normally never do, and then circle around a light fixture. After their nocturnal dance the bees would drop to the ground and start walking strangely. They were succumbing to their overlord, larvae of the fly Apocephalus borealis.
The life cycle of the parasitic fly is straight from a horror story. The female fly uses something called an ovipositor, which is like a hypodermic needle, to inject her eggs into the abdomen of the honeybee.
About a week later the larvae lurking within the abdomen wriggle into the bee’s thorax and start liquefying and devouring its wing muscles. Then, like in the movie “Alien,” they burst through the bee’s body, erupting from the soft space between its head and shoulder area.
“As far as we know this is a death sentence,” Dr. Hafernik said. “We don’t know any bees that have survived being parasitized by these maggots.”
As many as 80 percent of the hives that Dr. Hafernik examined in San Francisco Bay had been infected. Understanding more about how the infection spreads is important, he said, because although the infestations are not the main driver behind honeybee declines across the country, they could help collapse an already vulnerable colony.
A few years ago, John Hafernik detected in the walls of his house a thrumming hive of honeybees. He didn’t place a frantic call to the exterminator—he’s a bug-loving biologist at San Francisco State University—but grabbed some traps to experiment.
What he found was astonishing. Each dawn, his traps, which were equipped with lights, were filled with as many as 80 bees. That shouldn’t happen, because bees rarely go out at night; they use UV rays and polarized light to navigate and are “blind” without the sun. Even weirder, they swarmed the traps on January mornings when the weather was frosty. Cold kills bees. These were conditions in which no normal bee would be flying around.
The hive eventually died, which Hafernik credits with saving his marriage. “My wife was not excited about having bees in the walls,” says the 68-year-old San Franciscan. “The things we do for science.” But by then he had confirmed that his insect guests were the prey of a parasitic fly, Apocephalus borealis, that injected eggs into their bodies. For some reason that caused the bees to become deranged before perishing somewhat like the chest-bursting victim in Alien.
The ZomBee dance of death
Hafernik was originally responsible for discovering the gruesome interaction between honeybees and Apocephalus borealis. He noticed downed bees under electric lights in 2008 and put them in a jar as food for his lab’s praying mantises. He then forgot about the jar—when he came back, it was littered with brown pupae, which inspired a 2012 journal article fingering Apocephalus as the creator of what he calls “ZomBees.”
The fly had been known to parasitize bumblebees but not honeybees. The relationship might not have been noticed before, or perhaps it’s new. Hafernik favors the latter explanation. “If it was going on longer, there’d be more accounts from beekeepers and others,” he says.
At least one Bay Area beekeeper, Robert MacKimmie, has noticed an increase in afflicted specimens in recent years. “There are up to 200 bees a day or more disappearing from hives,” he says. On many mornings, he finds “bees in front of the hives crawling around in circles like they were drunk or poisoned.”
Here’s the “ZomBee” dance of death, in brief. Apocephalus, smaller than a fruit fly and looking like any other inconsequential pest, lands on a bee and jabs eggs through cracks in its abdomen. The parasite flies off and presumably expires thinking, “Job well done,” but it’s just the beginning of the host’s woes. The eggs mature, triggering something in bees that causes them to venture out at night in search of artificial light. They then fall to the ground and wander dazed as if they have neurological damage.
The night-stalking remains a mystery. “It’s quite possible it’s the parasite manipulating the host to move to a better place to complete its life cycle,” says Hafernik. “Or it could be the bee committing altruistic suicide, getting out of the hive to make it less likely other bees get infected.”
Whatever the reason, the bee then dies, only to start squirming in a week when maggots burst from its head or thorax. They wiggle away and form pupae to become adult flies and start the whole sequence anew. “Usually there’s a half-dozen or so [maggots] but occasionally you get a ‘lucky’ bee,” says Hafernik. “The record we have is 24 maggots coming out of a single bee.”
“ZomBees” have been found along the West Coast from Seattle to San Francisco to Santa Barbara. In a survey of 31 hives in the Bay Area, Hafernik found 77 percent were infected. “ZomBees” have also appeared in Vermont, Pennsylvania, the Hudson Valley, and South Dakota. Given that the parasite ranges all across North America, they could be in many other places.
Hafernik tracks sightings at ZomBee Watch, which geolocates reports from citizen scientists and answers questions like “Are parasitized honeybees more aggressive than normal?” (Unlike Hollywood zombies, they’re not, but still can sting if handled without forceps.)
Getting a bead on the extent of the infestation is important, as honeybees play a huge role in agricultural pollination and are already beset with afflictions, from blood-sucking Varroa destructormites to pesticides to fungal diseases to dysentery. With all these things harming bee populations, it’s hard to tell what role Apocephalus might play in Colony Collapse Disorder. “Most people who work on Colony Collapse Disorder think it’s caused by a variety of things acting simultaneously on bee colonies,” says Hafernik.
But aside from helping a species and an industry, keeping ZomBees in check is a smart move because, seriously, do you want to live in a world with dying, nocturnal bees kamikazeing into your windows and lamps? “That’s been a big problem for me,” says MacKimmie, who’s moved several of his hives due to complaints—including from one house where exhausted and dying ZomBees piled up so much the landlord had to blast them away with a leaf blower.
“My neighbors have sliding glass doors … and on warm nights they'd leave them open,” he says. “These bees that were infected would hit their porch light, then come in to look for other lights at night. So they had a dozen bees in their house and were kind of freaking out about it.”