Bumblebees Are Dying Out Thanks To Climate Change
Other animals are moving north to flee the heat, but bumblebees are not adapting—they’re simply dying out
Citizen scientists tracking Ohio bumblebees
‘Nature’s barometer’ facing challenges, possibly due to humans’ effect
LUCIANA MUSETTI In North America, there are 46 recognized species of bumblebees, such as the brown-belted bumblebee. Twenty-five percent of bumblebees face extinction because of factors such as global warming, habitat loss and pesticides, some experts say.
By Nolly Dakroury The Columbus Dispatch • Monday July 27, 2015 4:54 AM
Luciana Musetti is fascinated by bumblebees.
“They play a vital role to our environment, and they are beautiful, too,” Musetti, an entomologist and curator of the Triplehorn Insect Collection at Ohio State University’s Museum of Biological Diversity, said in an email.
When she can, she photographs them. That’s why she was excited to have stumbled upon bumblebeewatch.org, a website for citizen scientists devoted to tracking bumblebee populations in North America.
“The idea of the website is, if we can track where populations are now, we can start making conservation efforts,” said Rich Hatfield, one of the founders of the website.
The site, launched in January 2014, relies on contributors to submit images of bumblebees, which are then identified by experts and posted online.
There are about 46 recognized species of bumblebees in North America, and at least 25 percent of them are facing extinction, said Hatfield, a biologist with the Xerces Society, a nonprofit invertebrate-conservation organization.
He said one factor contributing to the dwindling bumblebee population is climate change.
A recent study, led by University of Ottawa professor Jeremy Kerr, tracked bumblebees over the past 110 years. It found that there are fewer bumblebees in the southern ranges of their natural habitats. In some cases, some species of bumblebees and other insects travel northward to escape rising temperatures, according to the study published in the journal Science.
Sam Droege, director of the U.S. Geological Survey native-bee inventory monitoring laboratory in Beltsville, Md., said tracking population fluctuations is not easy.
“Someone has to physically go through the specimen,” said Droege, who also is a collaborator on the Bumble Bee Watch project.
Because universities and governments can’t afford to send researchers out to look for bumblebees, having citizen volunteers is invaluable, he said. Anyone with a camera or a smartphone can photograph a bumblebee doing its job in yards or a park.
One unique trait of the teddy bear of the bee world is that it can survive in cooler environments better than other pollinators such as its cousin, the honeybee. It also visits flowers in low-light situations.
The University of Ottawa study suggests that because the bumblebee is accustomed to cooler climates, it is more susceptible to climate change.
In 2014, about 5,000 contributors submitted more than 4,500 photos of bumblebees. Through June of this year, more than 1,100 photos have been submitted from 37 states and nine Canadian provinces. Experts have so far identified 37 species.
One of the most-endangered bumblebee species is the rusty-patched bumblebee, or Bombus affinis.
MaLisa Spring, an entomology graduate research fellow at Ohio State, said this species once was common in Ohio but hasn’t been seen here in more than 10 years. However, the bumblebeewatch.org site has a photo that suggests a rusty-patched bee was spotted in Ohio in July. The photo is still pending verification by an expert.
Bumblebees are important pollinators because they can be more efficient pollinating some plants — cranberries and blueberries, for example — compared with other pollinators, said Denise Ellsworth, program director at Ohio State’s Department of Entomology.
They use a technique called buzz-pollination, in which bees create vibrations through their wing muscles, helping release pollen more easily.
Ohio farmers rely on bees to pollinate more than 70 crops, including apples, strawberries and pumpkins. Nationwide, honeybees pollinate more than $14 billion in crops each year, according to the U.S. Department of Agriculture.
Spring said other factors contributing to the loss of bumblebees in North America include habitat loss and fewer wildflowers, such as clover.
Droege said pesticides are another contributing factor. Some pesticides, such as neonicotinoids, seem to affect the bees’ navigation abilities, keeping them from returning to their hives or nests.
He said it’s time people start paying attention to the bees and their important role. “We’re most concerned about bumblebees. They’re deserving of our attention.
Updated May 7, 2013, 6:22 p.m. ET
Bee Deaths Put Crops at Risk
Mounting Toll on Pollinating Insects Imperils Over $20 Billion a Year in Harvests
By BILL TOMSON and RYAN TRACY
A USDA study released Tuesday reports that 31% of bee colonies died this past winter. Here, a honey collection in Homestead, Fla., last month.
The winter of 2012-13 was another rough one for honeybees, threatening an industry that is integral to a large part of fruit and vegetable production in the U.S.
A study released Tuesday by the U.S. Department of Agriculture said the number of honeybee colonies declined 31% last winter, by about 800,000 colonies, the latest reported toll of the mass die-offs with multiple causes that have been plaguing the U.S. for several years.
The impact of the premature deaths is significant for the honeybee industry and the broader agriculture industry. Beekeepers can generally bring populations back up during the warmer months, but while they do so, honey production can suffer. Also, the largest single driver of demand for bee colonies is California’s almond crop, which requires bees for pollination and blooms toward the end of the winter when bee populations are at their nadir.
Overall, more than $20 billion of annual harvests rely on pollination, according to U.S. estimates, with the almond harvest alone valued at $4 billion a year.
“We are one poor weather event or high winter bee loss away from a pollination disaster,” said Jeff Pettis, the U.S. Department of Agriculture’s bee research leader.
While the 31% loss during the 2012-13 winter is roughly in line with most winter declines since 2006, when the USDA says beekeepers began reporting the widespread hive losses, it is worse than the 22% decline in the 2011-12 winter.
The Department of Agriculture and the Environmental Protection Agency said last week that “multiple factors” were behind the population declines, including parasites, disease, poor nutrition and pesticide exposure.
Last month, the European Commission said it would soon restrict the use of three seed-coating pesticides known as neonicotinoids while scientists review concerns about the chemicals’ impact on bee health.
The neonicotinoid pesticides under debate are widely used in the U.S., including on corn in the Midwestern states where many beekeepers keep their hives during the summer. The pesticides are considered less harmful to the environment than other insect killers because they are often applied to the seed and contained within the plant, rather than sprayed onto fields.
U.S. officials said they didn’t have enough evidence to ban neonicotinoids and warned that other pesticides could be more harmful to the environment.
“There are nontrivial costs to society if we get this wrong,” said Jim Jones, who heads the EPA’s chemical safety office.
Two makers of the pesticides, Germany’s Bayer AG and Switzerland’s Syngenta AG, have said scientific evidence doesn’t support claims that their products are behind large declines in bee populations. But they have acknowledged that the pesticides might be dangerous to bees if used improperly—for instance, if a farmer allows a cloud of pesticide-laced dust to blow over an area where bees forage.
Premature bee deaths have been plaguing Jim Doan, owner of Doan Farms in Hamlin, N.Y., for seven years. Mr. Doan said he spends much of the year trying to repopulate his bee colonies to rent them to fruit growers who need to pollinate their apricots, peaches, apples and other crops.
He said he lost about half of his bees this winter, and although he will likely be able to fulfill most of his pollination contracts this year, honey production—another important source of his income—will be weak.
In part because beekeepers are splitting their colonies to replace lost bees—and colonies with fewer bees make less honey—the¬ honey yield per colony is falling. It took 2.6 million bee colonies to produce 147 million pounds of honey in 2012, according to USDA data. Roughly the same number of colonies produced 184 million pounds in 2004.
About 70% of the honey consumed in the U.S. is imported, said Bruce Boynton, chief executive of the National Honey Board, and that number has been increasing.
Meanwhile, there were just barely enough bees to pollinate California’s almond orchards this year, according to Dennis vanEngelsdorp, a University of Maryland scientist. The weather was perfect this year for pollination—bright and sunny—and that gave weakened bee colonies extra time to do their work, he said.
Each year, beekeepers from across the country truck more than 1.5 million colonies to the almond orchards. They set down boxed hives among the trees, and the insects forage from flower to flower, picking up and distributing pollen that the trees need to reproduce.
The largest almond grower in California, Paramount Farming Co. of Bakersfield, began scrambling last year amid reports of die-offs to avoid a shortage of bees, said Gordon Wardell, the company’s apiculturist. “I had backup bees lined up,” he said. Eventually, he found just enough: about 91,000 colonies to pollinate 46,000 acres of almonds.
Joe Traynor, a California bee broker, said he had to reduce the number of bees he provided to farmers this year by 5% because of the shortage.
Dan Cummings, chief executive of Capay Farms of Orland, Calif., said he doesn’t expect almond production to suffer for lack of honeybees, but a scarcity of pollinators might push prices higher. Honeybees are his second-largest expense, after fertilizer.
“I think we are going to have to work harder at [maintaining bees] and we are going to have to spend more money,” said Mr. Cummings, who is part of Project Apis m., a group funding research into making bees more viable.
Why are bees dying? The U.S. and Europe have different theories.
Beekeepers feel stung by insecticide manufacturer sponsoring OSU seminar
BROOKE LAVALLEY | DISPATCH FILE PHOTO
Dead bees cover the shingles beneath hives on a Pickaway County farm in early May of last year.
By Spencer Hunt
The Columbus Dispatch Tuesday March 5, 2013 6:08 AM
A company that makes an insecticide that many beekeepers say threatens their livelihood is co-sponsoring an Ohio State University seminar on protecting native bees.
Bayer Cropscience is giving Ohio State $5,000 to help defray costs for the March 14-15 OSU Extension Service seminar in Wooster on bumblebees and carpenter bees, and the environmental hazards they face.
Some critics say the company simply paid its way to get its message out.
Some Ohio beekeepers continue to blame the class of pesticide known as neonicotinoids for a mass die-off of honeybees reported in April. Their suspicion persists despite a state investigation that found no pesticide residue among the dead bees.
“I would say most beekeepers don’t really have a lot of confidence in this industry as being sympathetic to their cause,” said Jim North, a central Ohio beekeeper who found thousands of dead bees piled outside his Pickaway and Ross county hives last year.
Robyn Kneen, Bayer’s North American Bee Care Program manager, said she will discuss during the seminar the company’s commitment to promoting good bee care and pesticide-management practices.
She also said she will debate the notion that neonicotinoids are killing bees.
“There is no data to correlate that neonicotinoids would cause these types of losses,” Kneen said. “We just want to take the opportunity to put a different perspective in front of the public.”
According to an OSU news release, one of the seminar’s “highlights is Bayer Bee Care Program’s ‘ Beehicle,’ a specially wrapped vehicle that’s on a three-month journey across the Midwest providing bee stewardship workshops and expert presentations on issues impacting honeybee wellness.”
Neonicotinoids, which are used to coat seed corn, have been linked to honeybee deaths in other states and countries. On Jan. 31, the European Union proposed a two-year ban on the pesticides to better protect bees.
Denise Ellsworth, Ohio State’s honeybee-education program director, said Bayer seems sincere.
“They have been very upfront with me about wanting to support this effort,” Ellsworth said. “ They don’t have a finger in my agenda.”
Over a four-day span in April, millions of bees were found dead outside their hives in Delaware, Fairfield, Hardin, Miami, Pickaway and Ross counties. Beekeepers suspected neonicotinoids because the deaths occurred at roughly the same time corn was being planted.
Why are bees important? Ohio farmers rely on honeybees to pollinate more than 70 crops, including apples, strawberries and pumpkins. Nationwide, bees pollinate more than $14 billion in fruits and vegetables every year.
Ellsworth’s seminar is on native bees, including bumblebees and carpenter bees. She said the problems they face are similar to those honeybees face.
John George, president of the Ohio State Beekeepers Association, also doubts the validity of the Ohio Department of Agriculture investigation last year that found no pesticides in the dead bees.
“ It doesn’t pass the smell test,” George said.
Pesticides contribute to mass bee deaths
2 Studies Point to Common Pesticide as a Culprit in Declining Bee Colonies
Plight of the American bumblebee: Disappearing?
The photo provided by amateur Illinois bee spotter Johanna James-Heinz, shows a rusty-patched bumblebee, on Aug. 14, 2008, in Peoria, Ill. It is one of four types of bumblebees researchers say is in trouble. (AP Photo/Johanna James-Heinz)
Friday – 3/1/2013, 12:38am ET
AP Science Writer
WASHINGTON (AP) — It’s not just honey bees that are in trouble. The fuzzy American bumblebee seems to be disappearing in the Midwest.
Two new studies in Thursday’s journal Science conclude that wild bees, like the American bumblebee, are increasingly important in pollinating flowers and crops that provide us with food. And, at least in the Midwest, they seem to be dwindling in an alarming manner, possibly from disease and parasites.
Wild bees are difficult to track so scientists have had a hard time knowing what’s happening to them. But because of one man in a small town in Illinois in the 1890s, researchers now have a better clue.
Naturalist Charles Robertson went out daily in a horse-drawn buggy and meticulously collected and categorized insects in Carlinville in southern Illinois.
More than a century later, Laura Burkle of Montana State University went back to see what changed. Burkle and her colleagues reported that they could only find half the species of wild bees that Robertson found — 54 of 109 types.
“That’s a significant decline. It’s a scary decline,” Burkle said Thursday.
And what’s most noticeable is the near absence of one particular species, the yellow-and-black American bumblebee. There are 4,000 species of wild bees in America and 49 of them are bumblebees. In the Midwest, the most common bee has been Bombus pensylvanicus, known as the American bumblebee. It only stings defensively, experts say.
But in 447 hours of searching, Burkle’s team found only one American bumblebee, a queen.
That fits with a study that University of Illinois entomologist Sydney Cameron did two years ago when she found a dramatic reduction in the number and range of the American bumblebee.
“It was the most dominant bumblebee in the Midwest,” Cameron said, saying it now has pretty much disappeared from much of its northern range. Overall, its range has shrunk by about 23 percent, although it is still strong in Texas and the West, she said.
“People call them the big fuzzies,” Cameron said. “They’re phenomenal animals. They can fly in the snow.”
Her research found four species of bumblebees in trouble: the American bumblebee, the rusty-patched bumblebee, the western bumblebee and the yellow-banded bumblebee.
A separate Science study by a European team showed that wild bees in general have a larger role in pollinating plants than the honey bees that are trucked in to do the job professionally.
Those domesticated bees are already in trouble with record high prices for bees to pollinate California almond trees, said David Inouye at the University of Maryland.
Scientists suspect a combination of disease and parasites for the dwindling of both wild and domesticated bees.
Farmers’ lack of bees might be solved by going wild
Wild bees pollinate orchards more efficiently than rented honeybees, and for no cost, a study finds. They may provide the solution to the mass die-off of the domesticated bees from disease.
After observing bees in hundreds of fields on multiple continents, scientists calculated that wild bees, like the one shown here, were twice as effective as domesticated honeybees at prompting flowers to produce fruit. (Rufus Isaacs / February 28, 2013)
By Geoffrey Mohan, Los Angeles Times
February 28, 2013 | 5:10 p.m.
Farmers who have watched helplessly as a mysterious disease wiped out millions of domesticated bees needed to pollinate their almonds, apples and other crops may have an easy solution: make their crops more accessible to wild insects that do the job for free.
Not only are they cheaper, they fertilize blossoms with much greater efficiency, new research shows. After observing bees in hundreds of fields on multiple continents, scientists calculated that free-living bees were twice as effective as domesticated honeybees at prompting flowers to produce fruit. In addition, the proportion of flowers that matured to fruit improved in every field visited by wild insects, compared with only 14% of fields visited by rented honeybees, according to a report published online Thursday by the journal Science.
The findings have important implications for agricultural and land-use policies worldwide, said study leader Lucas A. Garibaldi, an agricultural scientist at the National University of Rio Negro in Argentina: Unless habitats for wild insects are protected and nurtured, farmers around the world could face a future of drastically lower yields.
Scientists have long warned that plowing landscapes into vast, single-crop fields and orchards eliminates the range of soil, wildflowers and other vegetation that is crucial to support multiple species of wild pollinators, including bees, flies, beetles and butterflies. As these insect populations have dwindled, farmers have resorted to using rented interlopers, generally Apis mellifera, during flowering season.
“Honeybees cannot replace the service wild bees provide,” Garibaldi said. “Biodiversity in agricultural landscapes matters and can help increase production.”
Garibaldi and his colleagues from North and South America, Europe, Australia, Africa and the Middle East analyzed data that had been collected in earlier studies based on direct observation of insect activity in small swaths of 600 fields in 19 countries. Researchers generally counted insects, flowers and pollen grains over varying periods of time on crops that represented different landscapes and management techniques. Some fields were heavily dependent on domesticated bees; in others, wild insects prevailed.
Even in fields dominated by domesticated bees, farmers often get more effective pollination services from native insects, said study coauthor Rachael Winfree, a pollination ecologist at Rutgers University in New Brunswick, N.J.
“At 90% of farms studied in New Jersey and Pennsylvania, native wild bees are fully pollinating the watermelon crop,” making rented bees unnecessary, Winfree said. But farmers don’t realize this.
‘“They’re thinking they need them but they don’t,” she said.
In California, the $3-billion almond industry spends $239 million annually to rent more than 1 million bee hives every year. To get that many pollinators, growers have been renting honeybees — an increasingly expensive practice as colony collapse disorder wipes out bees by the millions, for reasons that remain poorly understood.
In some California orchards, the data showed that pollination by rented honeybees got a significant boost when wild bees were present, possibly because the wild insects prompted the hired guns to fly more frequently among different varieties of trees in an orchard, said Claire Kremen, a UC Berkeley conservation biologist who contributed to the study.
However, she noted that most almond fields don’t receive that benefit because habitat for wild insects has been destroyed.
Laurence Packer, who studies wild bees at York University in Toronto and wasn’t involved with the new report, praised the work for its breadth and geographical scope. The findings are important and should be taken seriously, he said.
“Honeybees aren’t all they’re cracked up to be,” Packer said. “Other bees are far more important than people thought.”
Originally published Monday, September 24, 2012 at 11:43 AM
Washington state’s first ‘zombie bees’ reported
The infection is as grim as it sounds: “Zombie bees” have a parasite that causes them to fly at night and lurch around erratically until they die.
The Associated Press
The infection is as grim as it sounds: “Zombie bees” have a parasite that causes them to fly at night and lurch around erratically until they die.
And experts say the condition has crept into Washington state.
“I joke with my kids that the zombie apocalypse is starting at my house,” said Mark Hohn, a novice beekeeper who spotted the infected insects at his suburban Seattle home.
Hohn returned from vacation a few weeks ago to find many of his bees either dead or flying in jerky patterns and then flopping on the floor.
He remembered hearing about zombie bees, so he collected several of the corpses and popped them into a plastic bag. About a week later, the Kent man had evidence his bees were infected: the pupae of parasitic flies.
“Curiosity got the better of me,” Hohn said.
The zombie bees were the first to be confirmed in Washington state, The Seattle Times reported (http://is.gd/ji7UNX ).
San Francisco State University biologist John Hafernik first discovered zombie bees in California in 2008.
Hafernik now uses a website to recruit citizen scientists like Hohn to track the infection across the country. Observers also have found zombie bees in Oregon and South Dakota.
The infection is another threat to bees that are needed to pollinate crops. Hives have been failing in recent
years due to a mysterious ailment called colony collapse disorder, in which all the adult honey bees in a colony suddenly die.
The life cycle of the fly that infects zombie bees is reminiscent of the movie “Alien,” the newspaper reported. A small adult female lands on the back of a honeybee and injects eggs into the bee’s abdomen. The eggs hatch into maggots.
“They basically eat the insides out of the bee,” Hafernik said.
After consuming their host, the maggots pupate, forming a hard outer shell that looks like a fat, brown grain of rice. That’s what Hohn found in the plastic bag with the dead bees. Adult flies emerge in three to four weeks.
There’s no evidence yet that the parasitic fly is a major player in the bees’ decline, but it does seem the pest is targeting new hosts, said Steve Sheppard, chairman of the entomology department at Washington State University.
“It may occur a lot more widely than we think,” he said.
That’s what Hafernik hopes to find out with his website, zombeewatch.org. The site offers simple instructions for collecting suspect bees, watching for signs of parasites and reporting the results.
Once more people start looking, the number of sightings will probably climb, Hohn said.
“I’m pretty confident I’m not the only one in Washington state who has them,” he said.
Dramatic decline of bees caused by modern pesticides damaging their ability to home in on their hives, say researchers
By TAMARA COHEN
PUBLISHED: 13:02 EST, 29 March 2012 | UPDATED:13:02 EST, 29 March 2012
Bees are in dramatic decline, and scientists believe the answer may be in their homing instinct.
They have found the latest generation of pesticides is stopping the foragers finding their way back to the hive.
French researchers tagged 650 honeybees with tiny microchips attached to their necks which tracked all their movements.
Homing in on the answer: Researchers say pesticides are preventing bees from finding their way back to the hive
Half the bees were exposed to low doses of insecticide similar to what they would find in the wild, and when released, these ones were found to be two or three times more likely to die away from their hive.
Meanwhile British researchers, who have been working on bumblebees at Stirling University in Scotland found that when growing colonies were exposed to these chemicals, they were smaller than those not treated.
After six weeks the bumblebees – exposed to the same type of pesticide called a neo-nicotinoid – were up to 12 per cent smaller as it appeared less food was coming back to the nest.
Of even more concern to the Scottish scientists was that the number of new Queens – which go out and find new nests after winter – decreased by 85 per cent, which suggests a huge decrease in the number of new nests.
Neo-nicotoinoids, based on the chemical nicotine, were introduced as an insecticide in the 1990s, and have become the most popular for crops and gardens in the world.
Although bumblebees were already in decline, their numbers have fallen faster and honeybee populations are thought to have halved since the 1980s in Britain.
Both types of bees live in colonies where some of the inhabitants are foragers who travel up to a mile a day looking for new plants and bringing food back. Their lifespan can be just a week.
Mikael Henry of the National Institute of Agricultural Research in Avignon, France, said the chemicals seem to be attacking the bees’ navigation abilities, and if it continues at this rate, many colonies will not recover.
While pesticides are tested to make sure they do not kill bees – he believes they may be wiping them out indirectly.
He said: ‘Our study raises important issues regarding pesticide authorisation procedures.
‘So far, they mostly require manufacturers to ensure that doses encountered on the field do not kill bees, but they basically ignore the consequences of doses that do not kill them but may cause behavioural difficulties.’
Dr Dave Goulson, who worked on the Scottish study, also published in the journal Science, said: ‘We have seen big changes in the bees’ size and in particular in the number of queens, which is remarkable.
‘Putting these studies together, it suggests the answer may be the navigation abilities are being affected by base levels of neonicotinoid pesticides and this is having a substantial population impact.
‘Bumblebees pollinate many of our crops and wild flowers. The use of these pesticides on flowering crops poses a threat to their health and urgently needs to be re-evaluated.’
Neonicotinoids are applied to the seeds of plants rather than the plant itself which was thought to be more environmentally friendly.
They contain compounds which are thought to interfere with the bees central nervous system, and is having an impact on their memory and learning including finding their way back home – even from a short distance away.
The British Beekeepers Association advocates trying to improve rather than ban these pesticides, as new ones may prove to be even worse for bees.
Double dose of pesticide poses new danger for bumblebees
Government study suggests long-term exposure to chemicals can destroy colonies
MICHAEL MCCARTHY | MONDAY 22 OCTOBER 2012
The combination of two pesticides commonly used on UK fields can have damaging effects on the behaviour of bumblebees and cause their colonies to collapse, new research by British scientists has found.
And long-term exposure to individual pesticides – for up to a month – is also likely to have damaging effects, the scientists say. They argue that current safety tests are insufficient, as guidelines only demand pesticides are tested on bees for four days.
The findings, which come from a Government-funded study, represent the fifth major piece of research to appear this year linking the worldwide and worrying declines of bees to pesticides, and in particular to the use of the relatively new nerve-agent pesticides, the neonicotinoids.
This new study is considered particularly important because bees forage widely so are likely to encounter more than one type of pesticide.
The research was carried out at Royal Holloway College, University of London, as part of the Insect Pollinators Initiative, a £10m British programme looking at threats to pollinating insects such as bees, butterflies, moths and hoverflies.
Published last night in Nature online, the study reports that exposure to two commonly used pesticides, one a neonicotinoid and the other from a different pesticide family, a pyrethroid, at concentrations approximating what might be found in the field, impaired the natural foraging behaviour of bumblebees. This led to increased numbers of deaths and in some cases the failure of colonies. The compounds involved were made by major agrochemical manufacturers: the most widely used neonicotinoid, imidacloprid, manufactured by Bayer and already implicated in problems with bees in earlier studies, was one, while the pyrethroid was lambda-cyhalothrin, originally developed by Syngenta.
The Royal Holloway researchers found that bees exposed over a month to imidacloprid were less able to collect pollen effectively, which meant that their colonies had less food available and so could not raise as many workers.
On average, the percentage of workers leaving the colony and then getting lost was 55 per cent higher in those receiving imidacloprid than those that were not exposed to pesticides.
Two of the test colonies that were exposed to both pesticides together collapsed completely.
“The risk of exposure to multiple pesticides, or of the same pesticides being applied to different (adjacent) crops, is currently not considered when evaluating the safety of pesticides for bees,” the researchers say.
On long-term effects, they say: “Considering that we did not detect significant effects until two to four weeks into our study, the current… guideline of a maximum exposure of 96 hours for testing acute effects of pesticides on honeybees appears to be insufficient.”
A spokesman for Syngenta said yesterday: “There’s no evidence that pesticides damage the health of bee populations but yet again we see unrealistic research being used to prove the opposite.”