Noelle Swan

Archive for the ‘Honeybees’ Category

Honeybee experts worry uptick in urban beekeeping could compromise health of honeybee populations

In Honeybees, Wildlife and Ecology on October 25, 2012 at 9:47 am

This article first was published by ExploreUtahScience.org under the title Explosion in Urban Beekeeping Raises Concerns for Honeybee Population on October 25, 2012.

Photo Credit: FLICKR/dni777

Millions of buzzing residents have moved into Utah, as the number of new beekeepers registering with the state has increased eightfold since 2006.

That’s good news for local farmers and gardeners who depend on honeybees to pollinate their crops. The bad news is that the new arrivals could be bringing with them a rash of problems.

Several honeybee experts worry that in the hands of novice beekeepers, all those hives could become incubators for viruses and pests ready to hitch a ride to any of the thousands of commercial hives around the state.

Clint Burfitt suggests that this concern has been fueled by a fundamental shift in the scale of risk that face beekeepers today. “In the past, a [commercial] beekeeper could keep 1000 hives and might lose a few [to disease], but now a commercial beekeeper can have losses of 60 percent.” Burfitt is a state entomologist at the Utah Department of Agriculture and Food.

Colony Collapse Disorder, the nationwide phenomenon that first hit the news in 2006, contributes to these losses. By some estimates, the disorder is blamed for killing one quarter of the nation’s bees, resulting in a $12 billion loss to the agricultural economy.

Some beekeepers fear that should pest and viral infection spread to commercial apiaries, the results could be similarly devastating. “If one person isn’t knowledgeable or just doesn’t understand how to recognize or treat for [pests and pathogens], that jeopardizes everybody in that system,” says Burfitt.

The greatest opportunity for contamination comes when honeybees rob nectar from each others’ hives, inadvertently taking fungal spores, mites, and viruses with them. The varroa mite, the most common problem facing beekeepers, introduces viruses and bacteria directly into the bloodstream of bees. A rarer threat, the American foulbrood turns normally glistening, white honeybee larva into brownish goo that smells like dirty socks

“People get all fired up about [starting their new hives]. It goes pretty well at first, but summer gets busy and they let it languish. If it craps out, this time of year, robbers come looking for weak hives. Robber bees come in, pests jump ship and join the new hives,” says Chris Rodesch, Salt Lake County bee inspector. This activity can initiate a cycle that quickly infects an entire neighborhood of hives.

However, Rodesch maintains that commercial bees experience more risk of exposure when they are rented to farmers to pollinate crops, a common and lucrative practice. They are often trucked long distances and forage alongside bees from other parts of the country.

Should an outbreak of a particularly pernicious virus occur, the Department of Agriculture and Food is equipped to notify registered beekeepers and offer advice on symptoms and treatment. The Utah Bee Inspection Act mandates that all beekeepers register their hives with the department within 15 days of setting them up.

Nevertheless, there are shortcomings to the system. The inspection act does not require beekeepers to submit notification of hive losses. Such a requirement could make a big difference in identifying pests and pathogens before they reach the level of outbreak.

Further, many of the state’s beekeepers are either unaware of the registration requirement or unwilling to register their hives. Rodesch says that only half of the hives that he visits are registered with the state.

“Unless you see a lot of hives it’s hard to know if what’s happening in yours is normal or something that needs to be addressed,” says Rodesch. “That’s why the [beekeeping] clubs are really important.”

Cory Stanley, an entomology professor and honeybee specialist with Utah State University gives live demonstrations of various hive management techniques throughout the state, “I think that it is important to let the young beekeepers know the value of asking questions.”

UD Apiary research aims to take sting out of nationwide bee colony collapse

In Honeybees, Wildlife and Ecology on August 2, 2012 at 1:56 pm

This article first was published by WDDE.org, Delaware’s NPR News Station on August 2, 2012.

Bee colonies across the country began mysteriously collapsing in 2006, and have had scientists urgently seeking a cause of the meltdown ever since. Now, researchers at the University of Delaware believe they’ve uncovered clues to solving this problem that threatens the delicate natural balance on which the nation’s food supply depends.

At UD’s Newark apiary, where 22 hives are home to more than 1.3 million bees, researchers are focusing on an invasive parasite that can be as devastating to a bee colony as its Latin name, Varroa destructor, implies. The mites are one of several culprits that may be combining to cause Colony Collapse Disorder, which has resulted in the die-off of tens of billions of bees nationwide.

Debbie Delaney, a UD assistant professor of entomology and wildlife ecology, says combating one possible source of the decline might be as simple as mimicking a bee’s natural behavior, at least for small-scale beekeepers like the 300 apiarists in Delaware who host the majority of the state’s honeybees in their backyards.

While State Apiarist Robert Mitchell describes the status of the honeybee population in Delaware as “adequate,” he adds that colony losses have taken a toll at a time when the demand for pollination services continues to grow.

“Honeybees are responsible for the pollination of $10 million worth of wholesale fruit and vegetable value in the state,” said Secretary Ed Kee of the Delaware Department of Agriculture in an email reply. “This valuable resource must be protected.”

UD Apiary research aims to take sting out of nationwide bee colony collapse
Various stages of varroa mites.
Photo by Zachary Huang, http://cyberbee.net/gallery.

The varroa mite is one of the “primary forces behind the decline of the honey bees,” said Katy Evans, a UD graduate student spearheading Delaney’s study.

These little external parasites attack both adult honeybees and their brood, or young, by latching onto them and feasting on their blood. That may sound familiar to people used to swatting at mosquitoes, but varroa mites are no minor nuisance.

Although we can just barely see them with the naked eye, Delaney explains that it is a whole different story from a bee’s perspective.

“It’s as if we had a dinner plate attached to us sucking our blood,” she said.

To get to that blood, mites have to penetrate the bee’s exoskeleton, leaving behind a wound that is open to infection from additional pests and pathogens. When feeding on drones, or male bees, the mites deplete the drones’ protein and sperm levels and eventually render the bee incapable of flying. In addition to feeding on drones, the mites attach themselves to the brood of young bees in the early stages of their development.

“To make it even more awful, they vector viruses,” Delaney added. Just like a mosquito carrying malaria, or a tick bearing lime disease, these mites can transport and deliver new diseases directly into their hosts’ bloodstreams.

Delaney’s research at the UD apiary stems from observations she made in her backyard hives. So far, her bees have been healthy: no signs of virus, good honey production, and a strong population. She says that some of her bees have varroa mites, but they haven’t damaged the colony overall. She believes that the few mites on her bees at home have not had a chance to multiply because she employs a technique called hive splitting, which is modeled after bees’ natural tendency to swarm and establish two separate hives if their population outgrows the hive.

UD Apiary research aims to take sting out of nationwide bee colony collapse
Bee larva with 5 varroa mites on one side.
Photo by Zachary Huang, http://cyberbee.net/gallery.

Delaney is currently testing a theory that some natural beekeepers have claimed for years. During a hive-splitting period, bees don’t reproduce, and varroa mites have no baby bees to feed on. So the mite population dies off and takes so long to rebound that they never achieve numbers large enough to harm the colony.

Bill Leitzinger, amateur apiarist from Middletown and president of the Delaware Beekeepers Association has used the hive-splitting technique to control varroa mites in his hives for ten years. Leitzinger says when he was growing up, his father used chemicals to address mites and other problems around his few hives. He decided to do things differently.

“I have never used chemicals,” he said. “It used to be I was the weird one. Now most beekeepers are trying not to use chemicals.” He noted that the natural beekeeping movement evolved in response to research showing that chemicals applied to the hive can seep into the wax and remain in the hive for several years.

Delaney points out that miticides are not the only chemicals that remain in the wax. Pesticides and fungicides applied to plants miles away can stick to honeybees’ bodies during nectar collection and hitch a ride back into the hive where they, too, remain in the wax for years to come.

Recent research indicates that insecticides and parasites in non-lethal amounts can have a combined effect that becomes lethal. Delaney speculates that the combination of miticides and insecticides could have a similar effect. She hopes that her research will confirm that hive splitting is a viable alternative to chemical miticide application.

“If we can reduce in any possible way any type of pest that gets into the hive matrices or that the bees come in contact with, then I think that’s a very good thing,” Delaney said.

Harvard Study Shows Link Between Common Pesticide and Honeybee Colony Collapse Disorder

In Honeybees, Wildlife and Ecology on April 13, 2012 at 12:33 pm

This article first was published on Seedstock.com on April 10, 2012.

Researchers at Harvard School of Public Health have linked imidicloprid, a common agricultural pesticide to honeybee Colony Collapse Disorder, a mysterious phenomenon resulting in devastation of entire hive colonies. The dramatic decline in honeybees because of this phenomenon has worried scientists, farmers, and beekeepers alike, as honeybees play a vital role in pollination and fruit production in both natural and agricultural ecosystems. The results of the study were announced in early April in a Harvard School of Public Health press release and will be published in the June issue of the scientific journal Bulletin of Insectology.

Colony Collapse Disorder

Florida beekeepers first reported the bizarre symptoms of Colony Collapse Disorder in the winter of 2006-2007. In 30-90% of beekeepers hives, the worker bees, or drones, spontaneously abandoned the hive, leaving behind their queen and their young. Without the workers to sustain the hive, the queen and young soon died. The phenomenon was like nothing beekeepers had ever seen before.

“If the honey bees died because of pathogen infection or disease you would see many, many dead bees both inside and outside the hives,” says Chengshen Lu, HSPH assistant professor of environmental exposure biology and lead author of the study. In cases of Colony Collapse Disorder, beekeepers have not found any dead bodies inside the hive and very few near the colony at all.

Lu says that he and his colleagues were able to replicate Colony Collapse Disorder in a study in Worcester County, Massachusetts. The study consisted of four bee yards, each containing four hives exposed to varying levels of imidicloprid and one hive left untreated as a control. After 23 weeks, all but one of the treated colonies collapsed. While those treated with the highest dose succumbed first, even those treated with low concentrations (smaller than the amounts used in agriculture) collapsed.

About Imidicloprid

Imidicloprid is a neonicitinoid, a class of pesticides designed to attack the nervous system of pest insects. Originally approved for landscaping in 1994, imidicloprid has since become one of the most widely used agricultural pesticides. Lu explains that when imidicloprid is applied to seeds, it will grow with the plant, finding its way into all parts of the plant, including nectar, pollen, and fruit. Bees foraging for nectar drink the imidicloprid-laden nectar and transport imidicloprid-rich pollen back to the hive.

In the case of commercial bees, beekeepers frequently supply the hive with high-fructose corn syrup during winter months to extend honey production. (Lu and his colleagues used this same technique to administer exact doses of the pesticide in their study). Because much high fructose corn syrup is derived from corn that has been treated with imidicloprid, these synthetic feeds are also a source of poison for the fuzzy pollinators.

All in the Timing

Lu believes timing has masked the link between imidicloprid and Colony Collapse Disorder. In his study, the hives appeared healthy for months after exposure. Twelve weeks after dosing, bees were buzzing around productively. He says that previous studies have looked for evidence of immediate toxicity. “If they don’t see an immediate problem, they wrap up the study and move on to the next,” he says. He adds that while understanding this delayed response brings a much-anticipated answer to one mystery, it begs an equally mysterious question: Why does it take so long for the poison in the imidicloprid to affect the honeybees?

Lu says that the delay between exposure and symptom expression is longer than the life cycle of a worker bee, typically 30-40 days. “It takes a couple of generations to make the toxicity occur in a dramatic way.” That means that the bees that are dying are not the same bees that were first exposed to the poison. Lu aims to investigate this delay this year in an additional study.

What’s Next?

The EPA already lists imidicloprid as toxic to bees in high doses, but in the absence of evidence that chronic exposure could be harmful, still permits its use. Lu says that he has sent the EPA a copy of this study as a courtesy and hopes that it will encourage the agency to consider its recommendations.