- Author: Kathy Keatley Garvey
Wikipedia defines CCD as "an abnormal phenomenon that occurs when the majority of worker bees in a honey bee colony disappear, leaving behind a queen, plenty of food, and a few nurse bees to care for the remaining immature bees."
We were going through materials this week for the Celebration of Life and Legacy for UC Extension apiculturist Eric Mussen of the UC Davis Department of Entomology and Nematology, when we ran across his Oct. 9, 2007 presentation delivered as part of the UC Davis Department of Entomology's Distinguished Seminar Series.
We covered his seminar, which drew a capacity crowd and scores of questions. We still have his PowerPoint.
The news story bears repeating:
UC Davis honey bee specialist Eric Mussen fingered a line-up of prime suspects at his “BSI: The Case of the Disappearing Bees” lecture on Oct. 9, part of the UC Davis Department of Entomology's Distinguished Seminar Series.
Mussen identified malnutrition, parasitic mites, infectious microbes and insecticide contamination as among the possible culprits. It's a complex issue, he said, but one thing is certain: “It seems unlikely that we will find a specific, new and different reason for why bees are dying.”
Colony collapse disorder (CCD), a phenomenon where bees mysteriously abandon their hives, is not a new occurrence, said Mussen, the Extension Apiculturist at UC Davis since 1976.
“Similar phenomena have been observed since 1869,” he said. “It persisted in 1963, 1964 and 1965 and was called Spring Dwindling, Fall Collapse and Autumn Collapse. Then in 1975, it was called Disappearing Disease.”
“But the disease wasn't what was disappearing,” Mussen quipped. “The bees were."
Massive bee die-off also occurred during the winter of 2004-05, but only those who read bee journals knew about it, Mussen told the crowd in the campus Activities Recreation Center. The latest die-off caught the attention of the national media last fall when a Pennsylvania beekeeper asked researchers at Pennsylvania State University to look at samples of his dying bees in Pennsylvania and Florida. “The local media picked up the story and the rest is history, including yours truly on the Lehrer Hour.”
One-third of America's honey bees vanished this past year due to the mysterious CCD, characterized by almost total hive abandonment. Nearly all adult worker bees unexpectedly fly away from the hive, abandoning the stored honey, pollen, larvae and pupae. Usually they leave in less than a week, and only the queen and a few young workers remain, Mussen said.
Honey bees normally do not abandon their brood, he said. “Nurse bees” continually feed the young, which increase 1,000-fold in size in six days.
“That's like an 8-pound baby weighing 4 tons in six days,” Mussen said.
Mussen, who received the American Association of Professional Apiculturists' excellence award in January for his bee industry leadership and apicultural research publications, and was named the California State Beekeepers' Association's 2006 “Beekeeper of the Year” for his industry-wide contributions, finds the silence of the bees troubling.
“The real reason bees are important is that we rely on them for crop pollination,“ he said. Commercial honey bees pollinate about 90 of the country's crops, valued at $15 billion.
“One third of our U.S. diet depends on honey bees,” Mussen said. “If bees produce fruits and vegetables somewhere else, do we (Americans) want to be as dependent on food as we are on oil?”
Bees are especially crucial to California's 600,000 acres of almonds, he said. To pollinate the almonds, growers need 1.2 million bee hives, “but California doesn't have 1.2 million bee hives, so they have to be trucked here.”
That, he said, can add to the bee stress.
Mussen linked malnutrition as a key factor in CCD. Honey bee nutrition is “weather dependent,” he said. “The best-fed bees are the healthiest, while malnourished bees are less resistant.”
Malnutrition and climate-linked issues include: Did local weather events affect pollen-producing plants negatively?
- Was there a lack of bloom (nectar and pollen) due to lack of rain or too much heat?
- Was there reduced access to flowers due to excess rain?
- Did cold nights interfere with meiosis that led to “sterile” or “non-viable” pollens?
- Do these types of pollen contain the usual proteins, vitamins, minerals and lipids required by the bees?
Mussen said that many regions in the United States experienced significant drought in 2006. “The U.S. honey crop was off 11 percent, one of the lowest on record. The California crop was off 30 percent; North and South Dakota crops were off nearly 15 and 40 percent respectively.”
If there's malnutrition in August and September, that adversely affects the winter bees, he said. A mix of quality pollens is required to rear healthy winter bees.
Unlike the California definition based on amount of water in the reservoirs, the beekeepers' definition of drought is: Is there enough soil moisture to keep the flowers growing? "This year there was not,” Mussen said.
Malnourished bees are more susceptible to disease, predators and insecticides, he pointed out. The Varroa destructor mites, introduced here in 1987 from the Asian bee (Apis cerana), spread across the country in five years, killing the American bee (Apis mellifera), known as the European bee.
Compared to fruit flies and mosquitoes, “bees have a limited immune system; they're pretty anemic,” he said.
Another problem: “Varroa mites have become resistant to most legal chemical controls that used to keep them in check.”
Mussen cast suspicion on several viruses as CCD factors: the Kashmir bee virus, acute bee paralysis virus, deformed wing virus, black queen cell virus and the Israel acute paralysis virus.
“Honey bees have about 20 known viruses, most of which can cause disease,” he said. Some viruses remain latent, just like chicken pox in humans, which can show up as shingles later in life.
USDA scientists found the Israeli acute paralysis virus, in nearly all of the CCD colonies they tested, but none in the control group. In addition, they found the Kashmir bee virus in all the CCD colonies tested.
Also found in all the CCD colonies tested were the infectious microbes Nosea ceranae and Nosema apis. N. ceranae, a relatively new fungal disease of American honey bees, was imported from the Asian honey bee, Apis cerana. N. apis, its American counterpart, has been around for at least a century.
A favorite suspect among the beekeepers is neonicotinoids, chemicals designed to mimic the toxic effects of a neurotoxin from the tobacco family. The nicotine-like insecticide kills fleas on cats and dogs, and is used as a seed treatment and in side dressing and foliar spray applications.
“The insecticides enter various plant tissues and become distributed, systemically, throughout the plant,” he said. “Nicotine is so toxic to humans that if you put a drop of pure nicotine on your finger, you're dead.”
Neonicotinoids have been formulated to be nearly non-toxic to mammals, birds, and fish but remain extremely toxic to invertebrates.
Laboratory studies showed that miniscule doses of neonicotinoids increased the rate of learning in bees, but at high doses, bees failed to respond to training.
“It wasn't memory loss; it was intoxication,” Mussen said. “They were drunk.”
Another suspect: Gaucho® (imidacloprid), used as a seed treatment on sunflowers. Beekeepers claimed that when bees visited sunflowers, they never returned to their hives; “they lost their memory.” France and Spain banned imidacloprid, but “bees are still failing in their hives,” Mussen noted.
Mussen said no scientific documentation exists to blame imidacloprid for the bee die-off. A study found only 5 parts per billion maximum in the nectar of sunflowers and canola, he said. The Bayer fact sheet indicates that the insecticide is toxic to honey bees at 192 ppb.
Among the more “quirky” explanations for CCD: cell phone usage, alien encounters, honey bee “rapture” (where hive populations “ascend to that big honeycomb in the sky en masse”); and chemtrails, aircraft-released vapors.
“Some thought chemtrails was a military-industrial complex plan to kill all children and old people — and got the bees and birds by mistake,” Mussen said.
Mussen said he hopes that the current fascination with honey bees will lead to more research and more research funding. (End of story)
(Editor's Note: Dr. Mussen, a 38-year California Cooperative Extension apiculturist and an invaluable member of the UC Davis Department of Entomology and Nematology faculty, died Friday, June 3 at his home in Davis. He was 78. Attendance to the UC Davis-sponsored event celebrating his life and legacy is closed, but UC Davis distinguished professor Walter Leal will live-stream the event on Zoom. It will be permanently housed on YouTube. Registration for the Zoom webinar is underway at https://bit.ly/3dIyAhG. The YouTube account is at https://youtu.be/Kj5NuQ_rBuo. The webinar starts at 4 p.m. on Sunday. Aug. 28.)
- Author: Ben Faber
By: Carey Gillam, Reuters
Honey bees, critical agents in the pollination of key U.S. crops, disappeared at a staggering rate over the last year, according to a new government report that comes as regulators, environmentalists and agribusinesses try to reverse the losses.
Losses of managed honey bee colonies hit 42.1 percent from April 2014 through April 2015, up from 34.2 percent for 2013-2014, and the second-highest annual loss seen, the U.S. Department of Agriculture said in a report issued on Wednesday.
"Such high colony losses in the summer and year-round remain very troubling," Jeff Pettis, a USDA senior entomologist, said in a statement.
The 2014-15 yearly loss was down slightly from the 45 percent annual loss for 2012-2013 but well above the prior two years of annual measurements and above the benchmark of 18.7 percent that is considered economically unsustainable, USDA said.
Millions of honey bees are relied on to pollinate plants that produce a quarter of the food consumed by Americans. Beekeepers travel the country with managed hives to help the process.
But over the past few years, bee populations have been dying at a rate the U.S. government says must be addressed, and finding an answer has become a politically charged debate.
Beekeepers, environmental groups and some scientists blame a class of insecticide known as neonicotinoids, or neonics, used on crops such as corn as well as on plants used in lawns and gardens.
But Bayer, Syngenta and other agrichemical companies that sell neonic products say many factors such as mite infestations are harming the bees.
The White House has formed a task force to study the issue, and some lawn and garden retailers have been cutting use of neonics.
The Environmental Protection Agency is requiring a series of studies on neonic effects on bees and plans to issue the first of a series of assessments later this year.
The USDA report issued on Wednesday said colony losses were 23.1 percent for the 2014-15 winter months, typically the higher loss period. The 2014 summer loss of 27.4 percent marked the first time summer losses exceeded winter, and marked a surge from the 2013 summer loss of 19.8 percent, USDA said.
The results are considered preliminary and are based on survey responses from about 6,100 beekeepers managing 400,000 colonies, USDA said. Those beekeepers represent nearly 15.5 percent of 2.74 million U.S. bee colonies. A more detailed report is to be published later this year, USDA said.
- Author: Kathy Keatley Garvey
"Does colony collapse disorder (CCD) still exist?"
Eric Mussen, UC Cooperative Extension specialist in the Department of Entomology and Nematology at UC Davis says "yes."
But the winter losses are being attributed to many other causes. "Less than 10 percent of the losses are now attributed to CCD," Mussen points out.
CCD surfaced in the fall of 2006 when beekeepers starting seeing their colonies decimated. They'd open the hive, only to find the queen, the brood and the food stores. The adult workers? Gone.
"CCD still exists and it appears as though in cases where multiple other stresses combine to severely weaken the bees, then viruses can overwhelm the immune system and the bees fly away and die," Mussen says. "We do not know what causes apparently-sick bees to fly from the hive, and we still have a difficult time describing how all the bees could become affected so swiftly."
"As colony losses mounted, the beekeepers had to spend even more time monitoring the conditions of their colonies. They noted things that might be done to prevent some problems that seemed to be starting. So, we are better at preventing the losses, but the percentage for about 25 percent of our beekeepers is still way too high."
Mussen says that "the other 75 percent of the beekeepers are doing relatively well (5-15 percent losses), so we have leveled off in national colony numbers. If the 25 percent can better determine what is going wrong, we should see improved data in the future."
Scientists attribute CCD to a combination of causes, including pests, pesticides, viruses, diseases, malnutrition, and stress. The No. 1 problem in the hives, they agree, is the varroa mite. Mussen writes about those topics - and others in his newsletter, from the UC Apiaries and "Bee Briefs." Both are available free on his website.
Mussen, who is retiring in June after 38 years of service, was recently named the recipient of the 2013-14 Distinguished Service Award, sponsored by the UC Division of Agriculture and Natural Resources.
Mussen devotes his research and extension activities toward the improvement of honey bee health and honey bee colony management practices. Mussen, who joined the UC Davis department in 1976, is known throughout the state, nation and world as “the honey bee guru” and “the pulse of the bee industry" and as "the go-to person" when consumers, scientists, researchers, students and the news media have questions about honey bees.
- Author: Alison L Kent
“I'll be holding a precious resource in my hands, one that is essential to life on earth,” says Allen-Diaz. “I'll be placing my hands in Norm's hands to raise awareness about the value of honeybees.”
While raising money for education is certainly a worthy goal, as Allen-Diaz says, the event also draws attention to the plight of our most important agricultural pollinator. In 2006, a number of beekeepers in the Western U.S. noticed their hives had lost 30 to 70 percent of their worker bees. The phenomenon, now known as colony collapse disorder (CCD), is still not fully understood, though a number of factors are believed to be involved. They include habitat loss or degradation and fragmentation, poor nutrition, certain bee management and agricultural practices, natural and chemical toxins, diseases, and parasites. Any one of these factors can affect the insects' ability to combat any of the others. Isolating a single cause, if there is one, has proved elusive.
Many of the fruits and vegetables on the tables of the world are pollinated by insects, particularly bees, and if they were to disappear, our sources of plant food would be restricted to grains and not too much else. It's no wonder CCD is such a concern (for example, see the United Nations Environmental Program 2010 report on Global Bee Colony Disorder and USDA, Honey Bees and Colony Collapse Disorder.
As human population grows and becomes more urban, and as habitats get more fragmented, it is no longer adequate to focus conservation efforts merely in non-urban, non-working landscapes.
“We need to figure out how to accommodate as many native species as possible in these kinds of places,” says Patrick Huber of the City of Davis Open Space and Habitat Commission, which has adopted pollinator habitat enhancement as a working goal. The Commission is working to compile a GIS dataset of known big patches of habitat in Davis, in order map pollinator resources around town.
Huber is a geographer in the Landscape Analysis and Systems Research lab at UC Davis, where he focuses on spatial scale in conservation planning. He is working on a tool to help match gardeners with plants that will grow well in their regions, that are locally available, and that provide a network of resources for pollinators throughout the urban landscape and on into the agricultural landscape. For the moment this project is being piloted in Davis, but the hope is to expand it to other communities, tying in resources such as CalFlora.
- Planning for succession blooming (in the Central Valley, that means late winter through fall)
- Putting plants in clumps at least 4 feet long if possible (honeybees, especially, like to specialize)
- Putting in plants that provide both nectar and pollen (nectar is fuel for adult bees, pollen is protein for the young)
- Using native plants where possible; they're drought tolerant and have what our native bees need
- Avoiding most-toxic pesticides and herbicides
- Providing a clean source of water (a slow-dripping tap on a sloped surface is ideal; bees like to drink from very shallow sources)
- Providing cavity nest holes in wood for carpenter and other bees
- Leaving some areas of gardens unmulched for ground-nesting bees
There are ways the agricultural landscape can be made more hospitable, too. Neal Williams, professor of entomology at UC Davis, has been working on a project to install 600- to 800-meter plots of flowering plants alongside large fields as resources for pollinators. This has moved out of the trial phase into test plots in coastal and foothill areas as well as in the Central Valley.
Meanwhile, we can all help count our pollinators on May 8, the Day of Science and Service to celebrate 100 years of Cooperative Extension in California. We'll be conducting our own pollinator count here outside the ANR building in Davis: join us, or let us know about yours!
Many thanks to Kathy Keatley Garvey for use of her photos.
- Author: Marian I Chmieleski
Have you ever been out on a sunny day, walking barefoot happily through the clover when suddenly you yelp and begin to jump around trying to ease the sudden stinging pain in your foot? Yes, so have I. Well, the culprit is most likely the gentle little honeybee, one of nature's hardest working and least aggressive little beings. However, if a giant were going to step on me I'd use all my weapons to protect myself, too! Thus, the sad, negative reputation of the honeybee (Apis mellifera).
However, the honeybee is not only our friend, but also a very important part of our symbiotic natural family. According to National Geographic's most recent article (May 10, 2013), "About a third of our foods (some 100 key crops) rely on these insects, including apples, nuts, all the favorite summer fruits (like blueberries and strawberries), alfalfa (which cows eat), and guar bean (used in all kinds of products). In total, bees contribute more than $15 billion to U.S. crop production, hardly small potatoes." That's what makes the staggering disappearance of so many bees in the last few years such a troubling problem.
As you may have heard, during the winter of 2007 many beekeepers across the USA reported unusually large honeybee losses. The puzzling thing was that there were no piles of dead bees near the hives as happens if the bees are directly exposed to pesticides. It seems that the worker bees just began disappearing, leaving the queen and the young bees alone in the colony. However, the colony needs the worker bees to bring home the food and without them the hive and all the bees therein eventually dies. This is called Colony Collapse Disorder (CCD).
Over the years since that time studies have failed to conclusively identify the cause, but the result is that about 47% of the honeybees across the USA have been lost. (Figures from winter 2012-2013.) The EPA reports that several contributing factors are suspected:
- increased losses due to the invasive varroa mite (a pest of honeybees);
- new or emerging diseases such as Israeli Acute Paralysis virus and the gut parasite Nosema;
- pesticide poisoning through exposure to pesticides applied to crops bee management stress;
- foraging habitat modification
- inadequate forage/poor nutrition and
- potential immune-suppressing stress on bees caused by one or a combination of factors identified above.
What can we as gardeners do to help? We can, of course, avoid using pesticides in our gardens--especially neonicotinoids (approved for use in the US, but recently banned in the European Union). We can also provide a healthy and attractive habitat for honeybees. Enter the Yellow Dot Project (yellowdotproject.org). They not only publish a very extensive list of plants that are good food for honeybees, but also have connected with several nurseries in our area to identify for us exactly which plants on their shelves are best for the bees. Fantastic! All we have to do is look for the yellow dot on the plant i.d. marker. What could be easier?
I learned of the Yellow Dot Project on my visit to Annie's Annuals in Richmond last Saturday. Check out the website to see which plants in your garden are already at work helping the honeybees or just to find a "Yellow Dot" nursery to visit.