Tag Archives: colony collapse disorder

Saving the Honey Bee: Can New Genomic Clues Help Solve the Colony Collapse Mystery?

Image credits:
Daniel Olaleye.

Colony collapse disorder has been the scourge of U.S. beekeepers for more than a decade, contributing to a 30-40 percent plunge in commercial honey bee colonies since 2006. A threat to bees is a threat to people: bees help pollinate more than one-third of our crops, including almonds, apples, cucumbers, melons and squash. Their labors as pollinators produced $15 billion worth of crops in the United States in 2016 alone, according to the U.S. Department of Agriculture.

Scientists initially struggled to explain colony collapse disorder. But through careful detective work, they have identified a parade of horribles that may trigger the fatal syndrome, including climate change, pesticides and bee parasites – yet in order to save the bees, scientists need more than just identify the culprits. They need detailed genomic, cellular and physiological data on how these factors imperil bee health, and how the damage can be stopped.

One parasite to rule them all

For the western honey bee, no parasite is more destructive than the Varroa mites — Varroa destructor and Varroa jacobsoni. These tiny ectoparasites bite both free-flying worker bees and larvae in the hive. Scientists originally believed that Varroa mites feed on hemolymph, the bee equivalent of blood. However, newer research indicates that they may instead prefer a liver-like organ in bees known as the fat body. But their appetite explains only part of the havoc that these mites wreak: Varroa bites also deliver a horde of debilitating and fatal viral pathogens that can ultimately doom a bee colony to extinction.

 

Proximo Hi-C on the case

An international team of scientists led by Dr. Maéva Techer and Dr. Alexander Mikheyev at the Okinawa Institute of Science and Technology employed Proximo Hi-C to obtain complete genomes for V. destructor and V. jacobsoni — picking up genomic regions missed in previous versions of the V. destructor genome and assembling the first-ever complete genome for V. jacobsoni.

“Understanding the mechanisms of parasitism requires detailed information about the organization of the genome,” said Dr. Mikheyev.

Already, they have identified regions of both genomes that proved essential for Varroa mites to parasitize honey bees. The team hopes that these new and improved genomic tools will ultimately reveal cellular or physiological traits in Varroa that scientists could exploit at the molecular level to save honey bee colonies from infection and destruction.

“Our company’s mission is to empower genomic researchers to make breakthrough discoveries,” said Dr. Ivan Liachko, founder and CEO of Phase Genomics, which performed the analysis. “Our technology brings unique benefits to the field of genome assembly and we are very proud to be a part of a project of such global importance as this endeavor to help honey bees.”

The case of the blighted western honey bee

Fighting Varroa is a particularly crucial issue for the western honey bee, Apis mellifera, a relatively new host for Varroa mites. Varroa mites and their original hosts — the eastern honey bee, Apis cerana — are native to Asia, while the western honey bee hails from Varroa-free Europe. But when beekeeping practices brought eastern and western honey bees together in the 19th and 20th centuries, V. destructor jumped from eastern honey bees to their western counterparts and eventually spread globally. Over the past 20 years, V. jacobsoni has also started to infest western honey bee hives in Asia.

Western honey bees are particularly vulnerable to Varroa mites because they lack the behavioral, chemical and immune-based strategies of their eastern cousins to resist or tolerate infestation. The Varroa genomes harbor just the type of detailed information scientists need to help western honey bees.

Varroa mites take the lonely road to parasitism

In their first look at the new V. jacobsoni and improved V. destructor genomes, the team found something unexpected.

“The evolutionary trajectories of both mites, despite their similarities and close relatedness, were completely dissimilar,” said Dr. Mikheyev.

Both genomes had more than 200 genes under positive selection, sure signs of recent adaptation to their bee hosts. But less than 10 percent of the genes under positive selection in V. destructor were also under positive selection in V. jacobsoni. The researchers also discovered tandem duplications in dozens of genes, something they could only see using Hi-C. But again, there was high divergence between the Varroa species. About 63 percent of duplications were found only in the V. destructor genome, and just under half were unique to V. jacobsoni.

Some of the genes under selection or duplication in V. destructor were involved in cellular processes such as RNA splicing, alcohol response, membrane depolarization, and development of myofibroblasts and retinal cells. High-selection or duplicated genes in V. jacobsoni were involved in mitochondrial protein processing, vitamin K metabolism, pH response, and gonad development. The two Varroa species, it seems, took different cellular routes to bring bees to heel.

Despite these differences, many genes under positive selection in one or both Varroa species are involved in the same general physiological properties, such as metabolizing toxins, which could play a role in developing resistance to miticides. Genes undergoing duplication or positive selection in both Varroa mites are also involved in stress tolerance, molting, nutrition and reproduction.

From past to future

Image credits: Eric Ward.

This initial study is a work of history — revealing the genes under positive selection or duplication due to past and present selective forces on Varroa mites. Scientists need this detailed bounty of level of genomic data to help develop effective anti-Varroa measures.

“Curiously, in both species, genes involved in stress tolerance and detoxification were already under selection,” said Dr. Mikheyev. “This most likely happened before they ever faced miticides and suggests that they may have pre-adapted strategies for dealing with our chemical warfare strategies against them.”

The researchers have made both Varroa genomes publicly available, so other teams can mine the sequences for additional data about the evolution, adaptation and potential control of these parasites.

Dr. Mikheyev next wants to turn these genomic tools toward new goals, such as identifying genes that help Varroa mites switch hosts. That type of information may help scientists give the western honey bee a leg up over a new scourge that — so far — just won’t let go.

This is a guest article from Kaylee Mueller, of Phase Genomics.

How Colony Collapse Disorder Affects Honeybees and Humans

During the winter of 2006-2007, beekeepers around the country began reporting unusually high losses of their hives. Between 30 percent and 90 percent of honeybee hives disappeared virtually overnight.

As the Environmental Protection Agency (EPA) reported, a majority of worker bees in a colony would suddenly “disappear leaving behind a queen, plenty of food and a few nurse bees to care for the remaining immature bees and the queen.”

The strange occurrences had all the eerie mystery of a Wes Craven horror film, except it was insects that were dying, not people.

“As many as 50 percent of all affected colonies demonstrated symptoms inconsistent with any known causes of honeybee death,” the EPA said.

The widespread mysterious disease was labeled Colony Collapse Disorder (CCD) for want of a more precise term. Fears grew that this was a dire omen — honeybees would become extinct and with them, the flowers and plants that rely on bees for pollination and procreation.

Honeybees Provide Necessary Pollination for Many Human Foods

As the Agricultural Research Service explained, “About one mouthful in three in our diet directly or indirectly benefits from honeybee pollination. Commercial production of many high-value and specialty crops like almonds and other tree nuts, berries, fruits, and vegetables depend on pollination by honeybees. These are the foods that give our diet diversity, color and, flavor.”

Without honeybees, we would be bereft of much of our vegetation, creating even more malnutrition and starvation in the world.

Cause of Colony Collapse Disorder Still a Mystery

There have been many theories about the cause of CCD, including the frequency in recent years of hurricanes, tornadoes, wildfires, and smoke, and of course climate change. According to an online article in Vox citing the National Climate Assessment, average annual rainfall across the U.S. has gone up by five percent since 1990. These natural disasters may have upset the bees enough to cause them to flee their hives.

The EPA, however, has focused on the following factors that could contribute to CCD:

  • The invasive varroa mite (a pest of honeybees);
  • New or emerging diseases such as Israeli Acute Paralysis virus and the gut parasite Nosema;
  • Exposure to pesticides applied to crops or for in-hive insect or mite control;
  • Stress bees experience due to transportation to multiple locations across the country for providing pollination services;
  • Changes to the habitat where bees forage;
  • Inadequate forage and/or poor nutrition;
  • Potential immune-suppressing stress caused by one or a combination of the factors above.

Declines in Bee Populations Have Occurred throughout History

Like much media reporting today, the truth about CCD is quite different than the Doomsday scenarios. According to Norm Benson of Science 2.0, sudden declines in bee populations are nothing new. They can be traced back to Ireland in 950 AD and recurred again in 992 and 1493.

“In 1853, Lorenzo Langstroth, the father of American beekeeping, described colonies that were found ‘to be utterly deserted,’” Benson reported. “The comb was empty, and the only symptom of life was the poor queen herself.” He also noted, “In 1891 and 1896, many bees vanished or dwindled to tiny clusters with queens in the month of May, hence the name: ‘May Disease.’”

Why the Public Should Know about Colony Collapse Disorder

Entomologists, however, can see some benefit to calling the public’s attention to insect population declines such as Colony Collapse Disorder.

Writing in The Washington Post, Michael S. Engel, a paleontologist and entomologist at the University of Kansas, warned of the danger of singling out one group of organisms, such as honeybees, when discussing their impact on “the broader economy of nature.”

“Among all of life’s creatures, insects are some of the most vital, whether we notice their many services or not,” Engel pointed out. Just by “their staggering diversity and vast ecological connectedness,” insects are a fundamental, indelible part of virtually every ecosystem.

“Beyond pollination services, insects are also the food of many birds, mammals and fish,” Engel said. “Without insects, all of these would perish. Insects underpin, often unseen and ignored, the essential processes of our world.”

Bees Are Not Going Extinct and Crops Are Not in Trouble

Last year, Jon Entine, founder and executive director of the Genetic Literacy Project, argued that the apocalyptic warnings were premature. “Honeybee populations haven’t ‘crashed’ in the United States or elsewhere. Honeybees are not going ‘extinct.’ Crops are not ‘in trouble,’” he insisted.

Using U.S. Department of Agriculture (USDA) data, Entine posted a graph on the GLP website showing that honey-producing bee colonies in the U.S. are holding relatively steady at about 2.5 million colonies between 1995 and 2017. In fact, according to USDA figures, the U.S. honeybee population hit a 22-year high in 2016 before dipping slightly in 2017.

But the death knell reporting about CCD was so pervasive, it was often accepted without question that “the crucial pollinators could be edging towards extinction, plunging our entire food system into chaos,” Entine says. “The only problem is that it isn’t true.”

Entine offers several examples of false reporting about CCD:

The University of Florida IFAS Extension sums up the current state of CCD: “Colony Collapse Disorder may not be a new disorder. In fact, many colonies have died over the past 50-60 years displaying symptoms similar to those of CCD. The disorder as described in older literature has been called spring dwindle disease, fall dwindle disease, autumn collapse, May disease and disappearing disease. We may never know if these historic occurrences share a common cause with modern-day CCD.”

Anything that jeopardizes insect success undermines our own, Engel reminds us noting that “An insect apocalypse is our apocalypse.” We need to heed his warning.

About the Author

David E. Hubler is a veteran journalist and author. Prior to joining American Public University, he worked as an editor/writer for several news organizations including the Voice of America, United Press International and American Cities Business Journals. He received a bachelor’s degree in English from New York University and a master’s degree from the University of New Hampshire. His most recent book, “The Nats and the Grays, How Baseball in the Nation’s Capital Survived WWII and Changed the Game Forever” was published by Rowman & Littlefield Publishers.

 

Mushroom with antiviral properties could save the honeybees

Credit: Pixabay.

Since 2006, beekeepers in the United States have lost 30 to 90 percent of their colonies — and they haven’t recovered ever since. The ongoing decline in bee populations, which is experienced all over the world, has been attributed to ‘colony collapse disorder’ (CCD). This complex phenomenon is the result of many factors, perhaps as many as 61, according to one study. Over a third of our food supply depends on honeybees for pollination, so their loss could have dramatic effects on society and ecosystems at large.

For the past eight years, about 30% of colonies have been lost each winter

Besides pesticide use, habitat loss, climate change, and as most recently suggested, Glyphosate herbicides, scientists say that viruses are also among the prime drivers responsible for CCD. The Varroa mites, for instance, carry the “deformed wing virus”, which belongs to the family of Iflaviridae, so-called RNA viruses. Their genetic material only consists of one ribonucleotide strand, unlike the prevailing double-stranded DNA in mammals. When infecting honeybees, the virus causes the insects to develop deformed, non-functional wings, starving the colony.

A mycologist, however, might have found a way to save the bees from the virus carried by the mites. Paul Stamets is an expert at growing mushrooms and the author of a popular book on the subject. Thirty years ago, he first noticed that bees moved woodchips in his backyard to get closer to the mushrooms’ mycelium. At the time, Stamets thought that the honeybees were looking to extract sugars from the fungi, but it wasn’t until five years ago while researching the antiviral properties of mushrooms for humans that he made a striking connection: the honeybees may have been eating mushrooms to fend off viruses.

Stamets teamed up with researchers at Washington State University (WSU) and together devised a series of experiments in which they added small amounts of mushroom extracts to sugar water. The team exposed 50 bees from 30 different field colonies to the mixture at varying concentrations — and the results were simply stunning. Compared to bees that were fed only sugar water, bee colonies exposed to the mycelium broth experienced a 79-fold decrease in deformed wing virus after 12 days, and up to a 45,000-fold reduction in Lake Sinai virus, which is another virus linked to CCD.

The fact that experiments were made in the field, not just in the lab, make the results even more exciting. They suggest that it’s possible to develop a sort antiviral vaccine for bees that could save colonies from CCD.

Stamets has now designed a 3D-printed feeder that dispenses mushroom mycelia extract and hopes that by 2019 it will become widely available to beekeepers.

The findings appeared in the journal Scientific Reports

Glyphosate.

Glyphosate might be killing bees by messing with their gut bacteria

Glyphosate.

Credit: Pixabay.

Glyphosate, a broad-spectrum herbicide, has been in wide use since the 1970s with farmers looking to control weeds. Its manufacturer, Monsanto, has always claimed that the chemical only affects plants, being harmless to animals. A new study, however, shows that Glyphosate may be indirectly killing bees by disrupting the microbial community living in their digestive system. As such, the most popular herbicide in the world may be another important factor contributing to the alarming decline in bee populations all over the globe.

“We need better guidelines for glyphosate use, especially regarding bee exposure, because right now the guidelines assume bees are not harmed by the herbicide,” said Erick Motta, a graduate student at the University of Texas Austin, who led the research. “Our study shows that’s not true.”

Glyphosate is a non-selective herbicide, meaning it will kill most plants — including crops and weeds. It works by blocking a specific enzyme, the shikimic acid pathway, which prevents the plant from making key proteins required for growth. The shikimic acid pathway is not found in animals, which is why glyphosate is deemed non-toxic to humans.

However, the enzyme is used by some bacteria. Researchers at the University of Texas in Austin wondered whether glyphosate might be affecting bacteria strains living in the intestines of honey bees (Apis mellifera). They collected 2,000 bees from a hive and fed them sugar syrup dosed with herbicide levels they might encounter in real life.

Three days after they returned to their hives, the glyphosate-exposed bees had fewer Snodgrassella alvi bacteria in their guts than those which were not exposed. Confusingly, the bees that got the highest dose of glyphosate had a microbiome closer to optimal levels compared to bees that received the lowest dose of the herbicide. The researchers say that this may be due to the fact that bees with the highest dose died, leaving behind the resistant variety.

Things become clearer in later tests that showed that glyphosate-laden bees had five times less of the S. alvi bacterium. And when the researchers cultured the bacteria in a petri dish, its growth was very slow or stopped altogether when exposed to a high dose of glyphosate.

Writing in the Proceedings of the National Academy of Sciences, the authors suspect that changes in the bee’s microbiome make the bees more vulnerable to infections. Only 12% of the bees fed with glyphosate survived an infection from Serratia marcescens compared with 47% that were not fed glyphosate. S. marcescens is a bacteria that is widely found in beehives and bee guts that can invade other parts of a bee’s body, leading to lethal infections.

“Studies in humans, bees and other animals have shown that the gut microbiome is a stable community that resists infection by opportunistic invaders,” Moran said. “So if you disrupt the normal, stable community, you are more susceptible to this invasion of pathogens.”

S. alvi lines part of the gut wall and, as such, could act as an insulating layer against the potentially lethal S. marcescens. Additionally, S. alvi also secrets a chemical that can disrupt the invading bacterium.

The findings offer an alternative explanation for the massive decline in bee populations seen all over the world. For instance, beekeepers in the U.S. lost 42.1 percent of their bee colonies in just one year, between April 2014 and April 2015.

“Since the 1980s, honeybees and beekeepers have had to deal with a host of new pathogens from deformed wing virus to nosema fungi, new parasites such as Varroa mites, pests like small hive beetles, nutrition problems from lack of diversity or availability in pollen and nectar sources, and possible sublethal effects of pesticides, ” the USDA notes. But deaths began to spike in the middle of the past decade, when a phenomenon in which bees deserted their hives and died en masse – later named colony collapse disorder – began sweeping hives worldwide. “Commercial keepers were particularly prone to summer losses.”

Previously, scientists have linked colony collapse disorder (CCD) with pesticides, habitat loss, climate change, parasites, stress, and lack of flowers. In this constellation of stressors threatening the most important pollinators on the planet, glyphosate may also pose an important risk.

“It’s not the only thing causing all these bee deaths, but it is definitely something people should worry about because glyphosate is used everywhere,” said Motta.

The findings also raise some important questions about glyphosate’s safety. Perhaps it is affecting the microbiome of other animals, including humans. Previously, the science has been conflicting in its assessment of whether the chemical is carcinogenic or not.

New Technology Could Keep Bees Buzzing for Years to Come

If it weren’t for bees and other pollinators, we wouldn’t have blueberries, tomatoes, avocados, almonds, apples, broccoli, vanilla and many more of the fruits, vegetables and nuts we eat daily. This list could go on and on. In recent years, mass die-offs of bees have become a more real and more urgent threat than ever before.

A forager collecting pollen. Image credits: Jon Sullivan.

Colony Collapse Disorder and other issues caused by many potential culprits — including insecticides, disease, climate change and mites — have been causing bee populations to dwindle. Although they now seem to be rallying a bit, it’s still important to take steps to protect them.

A New Bee Tracking Technology
Saving the bees is the motivation behind a new device that can help scientists keep tabs on the health of bee populations.

Created by researchers at universities in Missouri and North Carolina, the acoustic listening system can pick up the sounds bees make in a certain area and relay that data back to scientists. This information could warn researchers about a potentially declining bee population and let them know where to go to find out more.

The technology uses a small microphone to capture the pitch of the buzzing of bees as far as nine to 16 feet away. The microphones are attached to a device used to store the data, such as a USB drive. They can record for around 96 hours before they need to be recharged.

Benefits and Challenges

While the system isn’t perfect, it’s much cheaper and more efficient than sending teams out to survey bee populations on foot. The devices let researchers know where they should go to get the best information and warn them about trouble spots. The device is also more accurate than trying to count the bees visually.

The recordings collect detailed information about the frequency of the buzzing they pick up, which scientists can use to learn about the bees in the area. Bees that are different sizes or shapes or have different tongue lengths buzz at different pitches.

This information could be useful to farmers because different kinds of crops require different pollination methods. The system could let farmers know about a potential drop in the bee populations they need to pollinate their fruits and vegetables.

Another important benefit of the system is that it doesn’t disturb the populations it monitors. Other tracking methods involve trapping bees or taking samples. Although these methods are more accurate than some others, they end up harming or even killing the bees in the process of trying to help them.

Continued Testing

To start out, the research team on this project tested out their listening system in the Rocky Mountains of Colorado to avoid background noise. They’re now moving on to farms, which are likely to be noisier because they’re less remote.

The researchers are continuing to test their system, and are considering expanding its use for other applications. They’re even working on a smartphone app, so anyone can use the devices to listen to the bees.

It can be challenging to collect accurate information on bee populations and determine what might be causing problems in the health of bee colonies. This device could prove helpful, though, in helping us learn more about the bees we depend on for so much of our food. We should do everything we can to help protect the bees — both for their sake and for ours.

Bio:

Emily works as a conservation and sustainability freelance writer, covering topics primarily in climate change and endangered species. To read more of her work, check out her blog, Conservation Folks, or follow her on Twitter.

Bees get much needed win as US court rules against neonicotinoid pesticide

It’s been a very rough period for bees. Bee numbers have been dropping at alarming rates, and the growing consensus seem to be that only limiting pesticide use (especially for some pesticides) can save them. Now, a US court overturned federal approval for a new formulation called sulfoxaflor, basically banning the pesticide.

Pesticides killing bees

Image via Discover Magazine.

The main problem is with neonicotinoids – a class of neuro-active substances linked with a swarm of negative environmental effects, including honey-bee colony collapse disorder (CCD) and loss of birds due to a reduction in insect populations. Sulfoxaflor is a neonicotinoid; on May 6, 2013, the United States Environmental Protection Agency approved the first two commercial pesticide products that contain sulfoxaflor, marketed under the brand names “Transform” and “Closer”, to the Dow Chemical Corporation. However, the decision was appealed and now, the U.S. 9th Circuit Court of Appeals issued a ruling overturning the EPA’s approval of sulfoxaflor, finding that the EPA had relied on “flawed and limited” data, and its green light was unjustified given the “precariousness of bee populations”.

Circuit judge Randy Smith said:

“I am inclined to believe the EPA… decided to register sulfoxaflor unconditionally in response to public pressure for the product and attempted to support its decision retrospectively with studies it had previously found inadequate.”

This decision can also be appealed.

Neonicotinoids have grown popular for protecting crops and orchards from unwanted pests, but in recent years, there has been increasing evidence that they also damage pollinators and disrupt their navigation systems, with major impacts worldwide.

Neonicotinoid pesticides can disrupt bee navigation (Image: Zhang Bo/Getty)

Striking contradictions

The strange thing about the legality of neonicotinoids is that the European Union banned most of them in 2013, as part of an effort to protect bees. An even larger investigation on banning more pesticides will be launched this autumn. However, last month, the EU approved the use of sulfoxaflor, while leaving final decisions on its use to national regulators, despite the European Food Standards Authority warning that “missing information” about sulfoxaflor meant that “a high risk to bees was not excluded”. Meanwhile, in the US, most neonicotinoids are still allowed for use, but sulfoxaflor has been banned. This creates a lot of confusion and misunderstanding.

“The public will be justifiably confused and concerned,” says Matt Shardlow, CEO of Buglife, a British group that campaigns against neonicotinoids.

Answering Questions

The lead attorney on the above mentioned lawsuit challenging the EPA’s approval of the pesticide sulfoxaflor took the time to answer some questions on Reddit. Here are some of the most interesting insights:

Question: What can the average person do to help bees?

Answer: First off, when buying ornamental plants for your home garden, make sure that they don’t come pre-treated with neonics. Unfortunately, many big nurseries are still selling flowers that are sprayed with neonics.

Q: Why do you have to say in response the NPR article basically saying everything is fine and the numbers reported don’t really tell the story at all?

A: First, we cannot expect native pollinators to stand in for commercially kept honeybees. Native bees are great, but where are we going to find the 1.5 million colonies it takes just to pollinate California’s almond crop each January? Second, every indication is that native bees have been taking it in the ear as well, and that’s a huge environmental impact in its own right.

Q: Thanks a lot for fighting the good fight, my question is how much other stuff needs to be removed to save bees in your opinion?

A: The hope is that we will eventually find a way to get off the toxic treadmill of evermore reliance on pesticides. It’s a social change, and it’s not going to happen on its own. It’s going to take commitment and real action on the part of government, corporate America, and all of us.

Q: What is going to replace neonicotinoids? Is the alternative better or worse for bees and farmers?

The hope is that we will eventually find a way to get off the toxic treadmill of evermore reliance on pesticides. It’s a social change, and it’s not going to happen on its own. It’s going to take commitment and real action on the part of government, corporate America, and all of us.

Q: What do you think will really happen if bees go extinct?

A: The reality is that commercial beekeepers will go extinct (read, bankrupt) long before honeybees. But the impact on agriculture and our diet will be essentially the same, because many of our most important crops absolutely require commercially kept bees for pollination. Agriculture as we know it just wouldn’t be possible without commercial beekeepers.

 

Bees use natural vaccines for their youth

When it comes to vaccines, the young bees don’t really have a choice – they’re naturally immunized against specific diseases commonly found in their environment. For the first time, researchers have figured out just how they do it.

Busy Bee

Researchers from Arizona State University, University of Helsinki, University of Jyväskylä and Norwegian University of Life Sciences made the discovery after they studied a bee blood protein called vitellogenin (VTG). VTG, an egg yolk precursor protein, is expressed in the females of nearly all oviparous species. VTG provides the proteins that are a source of nutrients during early development of egg-laying (oviparous) vertebrates and invertebrates. For bees, vitellogenin molecules are deposited in fat bodies in their abdomen and heads. The fat bodies apparently act as a food storage reservoir. Now, scientists report that it also plays a key role in protecting baby bees against diseases.

“The process by which bees transfer immunity to their babies was a big mystery until now. What we found is that it’s as simple as eating,” said Gro Amdam, a professor with ASU’s School of Life Sciences and co-author of the paper. “Our amazing discovery was made possible because of 15 years of basic research on vitellogenin. This exemplifies how long-term investments in basic research pay off.”

The process may be simple, but identifying its underlying mechanism was anything but – it took 10 years to figure it out. Co-author Dalial Freitak, a postdoctoral researcher with University of Helsinki adds:

“I have been working on bee immune priming since the start of my doctoral studies. Now almost 10 years later, I feel like I’ve solved an important part of the puzzle. It’s a wonderful and very rewarding feeling!”

How it works, and why it matters

IMG_2397

Each honey bee colony has only one queen, and she almost never leaves the nest, so the workers have to bring food to her. But the pollen that is used to create the “royal jelly” that the queen eats can also contain bacteria and pathogens picked up by the workers in the outside world. So when the queen eats it, the pathogens are transferred to her body, and pieces of bacteria are bound to VTG, and are also carried to the eggs. Unwillingly, the young bees are naturally vaccinated and protected from a swarm of diseases that might harm them.

Unfortunately though, there are still many diseases against which bees aren’t protected – but the good thing is that now that researchers understand how “bee vaccines” work, they can develop actual vaccines to protect the insects.

“We are patenting a way to produce a harmless vaccine, as well as how to cultivate the vaccines and introduce them to bee hives through a cocktail the bees would eat. They would then be able to stave off disease,” said Freitak.

During the past six decades, managed honey bee colonies in the United States have declined from 6 million in 1947 to only 2.5 million today; and recently, their numbers are dwindling more and more. Despite ongoing research and efforts, there is no definite solution against the problems they are facing. To make things even worse, colony collapse disorder is destroying beehives at an unprecedented level.

Pollinators (especially bees) are instrumental for a healthy economy and critical to food security, contributing 35 percent of global food production. We depend on bees, and we’re not taking care of them properly. Developing a synthetic, cheap bee vaccine could be huge.

“Because this vaccination process is naturally occurring, this process would be cheap and ultimately simple to implement. It has the potential to both improve and secure food production for humans,” said Amdam.

The findings appear today in the journal PLOS Pathogens.

 

 

Pollinating Bees are Worth Billions, and We’re Still Not Protecting Them

Wild bees provide environmental services worth $3,250 (€2,880) per hectare per year – accounting for billions, globally. Writing in Nature Communications, study authors quantify how much bees are doing for us, and stress that despite all their immense value, we still don’t have a concrete plan to stop their numbers from dwindling.

Image via Fabulous Arizona.

We’ve written extensively on the situation of bees – their numbers are dropping fast, and we still don’t know exactly why (it’s probably a combination of pesticide use, destruction of habitats, climate change and parasitic infections). Scientists have raised alarm signals about this since 2006, when beekeeper Dave Hackenberg inspected 2,400 hives wintering in Florida and found 400 of them abandoned — totally empty. Today, most bee species are in decline, with annual regional losses as high as 60 percent. When you consider that it’s not just about saving bees, it’s also about the services bees do for us, one can only ask: “Are we doing enough?”.

[Also Read: Bees make blue honey after eating M&Ms]

In this study, researchers followed the activities of nearly 74,000 bees from more than 780 wild species. They found that on average, wild bees contribute $3,251 per hectare ($1,315 per acre) to crop production, even more than “domestic” bees, which were worth $2,913 per hectare. The study helps put a “dollar figure” over an environmental service which is usually hard to estimate.

But not all bees are as useful – researchers were surprised to learn that 2% of wild bee species, the most common types, fertilise about 80% of bee-pollinated crops worldwide. In this way, bees are like football players.

“There are a few who really make a lot of money, like (Cristiano) Ronaldo and (Lionel) Messi, then another large group who can make a living from football. And then there’s 99.9 percent who just play for fun,” said lead author David Kleijn, of Wageningen University and Research Center in the Netherlands.

The rest, while still crucial for their local ecosystem, were not as involved in agricultural crops, but authors stress that their protection is just as important.

“Rare and threatened species may play a less significant role economically than common species, but this does not mean their protection is less important,” said David Kleijn, a professor at Wageningen University in the Netherlands, who led the study.

Image via Myrmecos

The research also focused on bee populations in the UK, and reports that 85 per cent of the UK’s apple crop and 45 per cent of the strawberry crop relies on bees to grow. Alone those two crops brought in £200 million to Britain in 2012. The UK is considering drastically reducing or eliminating pesticides to protect bee populations.

“Hundreds of thousands of us are asking why the government is even considering allowing harmful pesticides back on British fields. We’re calling for Environment Minister Liz Truss and the government to keep the ban on bee-killing pesticides, with no exceptions. “If we want future generations to be able to eat home-grown strawberries and Bramley apples, we have to keep bee-killing pesticides off our land.”

All in all, the science is consistent on this one – we need to find a way to protect bees; for their sake, and for ours.

“Crucially, the commonest wild bees are the most important, which gives us the ‘win-win’ situation where relatively cheap and easy conservation measures can support these and give maximum benefit for the crops,” said Pat Willmer, a professor of biology at Scotland’s University of St Andrews. “For example, planting wild flowers with wider grassy margins around crops, as well as less intensive or more organic farming, all enhance abundance of the key crop-visiting bees,” he told Britain’s Science Media Centre (SMC).

Pesticide limit may be the last resort to save the bees, White House says

With bee numbers dropping dramatically in the last years, it’s time to take some drastic measures, and a White House task force including participation from more than a dozen federal agencies has concluded that limiting pesticide use may be the last resort we have to maintain bee numbers.

Image via Eco Watch.

The humble bee plays a key role in agriculture; in the US alone, they provide environmental services through pollination estimated at $10-15 billion every year, according to the USDA.. If bees continue to vanish at these rates, then we can expect anything from rising prices in common foods to actual food shortages – it’s high time some drastoc measures are taken.

But there are even more reasons to worry – if bee populations are collapsing and we don’t know why, how long will it be before something else collapses? John P. Holdren, assistant to the president for science and technology, said in an interview that they are concerned about the “canary in the coal mine” phenomenon.

“If honeybee colonies are collapsing for a reason we don’t understand, what is that telling us about our overall impacts and understanding of the ecosystems on which we depend?”

While there are many elements factoring into the bees’ demise, pesticides were deemed the main culprit by most studies.

“Mitigating the effects of pesticides on bees is a priority for the federal government, as both bee pollination and insect control are essential to the success of agriculture,” the report said. “These complex considerations mandate care in all pesticide application.”

The strategy they are proposing will also monitor the way in which forests burned by wildfire are replanted, the way offices are landscaped and the way roadside habitats where bees feed are preserved. The destruction of their natural habitats is another one of the major problems. The plan calls for restoring 7 million acres of bee habitat in the next five years.

The report also highlights the fact that we don’t yet understand what is happening to bee populations, so they recommend an investment of $82.5 million in bee research. This has been hailed by people working in agriculture as well as biologists. After all, for all the work that bees put, and all the benefits we yield from that, it’s about time we started a major project to protect them.

“I have to say that it is mighty darn lovely having the White House acknowledge the indigenous, unpaid and invisible workforce that somehow has managed to sustain all terrestrial life without health-care subsidies, or a single COLA, for that past 250 million years,” said Sam Droege, a U.S. Geological Survey wildlife biologist and one of the country’s foremost experts on native bee identification.

 

Bee numbers dropping at incredible rates

Something is killing off the bees; it’s likely us, and we’ll all have to pay the price. In fact, in many areas of the world, we already are.

Total annual loss (%) 2014-2015 by state. Respondents who managed colonies in more than one state had all of their colonies counted in each state in which they reported managing colonies. Data for states with fewer than five respondents are withheld. Steinhauer et al, 2015.

 

“If you’ve ever eaten a strawberry or a blueberry, you ought to thank a bee,” comments Toni Burnham, the president of the Maryland State Beekeepers Association.

Something’s killing the bees

The statistics are extremely disturbing; beekeepers in the U.S. lost 42.1 percent of their bee colonies in just one year, between April 2014 and April 2015. This is just an analysis of the preliminary results, but the emerging trend is already worrying. It’s normal to lose some beehives, it happens every year, but the destruction of bee hives is not slowing down – it’s accelerating.

“Beekeepers do not only lose colonies in the winter but also throughout the summer, sometimes at significant levels. Responding beekeepers reported losing 42.1% of the total number of colonies managed over the last year (total annual loss, between April 2014 and April 2015). This represents the second highest annual loss recorded to date,” the report writes.

So what is killing the insects? The answer is complex and involves several factors.

“Since the 1980s, honeybees and beekeepers have had to deal with a host of new pathogens from deformed wing virus to nosema fungi, new parasites such as Varroa mites, pests like small hive beetles, nutrition problems from lack of diversity or availability in pollen and nectar sources, and possible sublethal effects of pesticides, ” the USDA notes. But deaths began to spike in the middle of the past decade, when a phenomenon in which bees deserted their hives and died en masse – later named colony collapse disorder – began sweeping hives worldwide. “Commercial keepers were particularly prone to summer losses.”

The words that seem to always pop up in this discussion are “Colony Collapse Disorder” (CCD). CCD is a phenomenon in which worker bees from a colony abruptly disappear. Beekeepers throughout the entire world have reported massive rates of CCD in recent years, but the mechanisms still remain unknown. Pesticides (especially neonicotinoids) are the main suspect, but loss of habitat, pollution and infection with various pathogens also likely contribute.

A study that came out in February 2015 concluded:

“Bees of all species are likely to encounter multiple stressors during their lives, and each is likely to reduce the ability of bees to cope with the others. A bee or bee colony that appears to have succumbed to a pathogen may not have died if it had not also been exposed to a sublethal dose of a pesticide and/or been subject to food stress (which might in turn be due to drought or heavy rain induced by climate change, or competition from a high density of honey bee hives placed nearby). Unfortunately, conducting well-replicated studies of the effects of multiple interacting stressors on bee colonies is exceedingly difficult. The number of stressor combinations rapidly becomes large, and exposure to stressors is hard or impossible to control with free-flying bees. Nonetheless, a strong argument can be made that it is the interaction among parasites, pesticides, and diet that lies at the heart of current bee health problems.”

Why we should care

Saving bee colonies is important not only for the bees themselves, but also for us. Something that many people tend to neglect is that as pollinators, bees provide valuable environmental services for agriculture. It’s estimated that in the US alone, pollination services are worth $10 billion to $15 billion a year. The worldwide value is incommensurable.

If bees continue to vanish at these rates, then we can expect anything from rising prices in common foods to actual food shortages. When you consider that some agricultural areas rely almost entirely on bees for pollination, the situation gets even more dire. The first ones who have to take measures are actually the beekeepers.

“As long as beekeepers are willing to put more money and hard labor into it, we can come back and rebuild our colonies and numbers,” explains Dr. Heather Mattila, a honeybee biologist at Wellesley College. “But whether this is all sustainable is an open question.”

But the problem is much bigger than this, and CCD is just another symptom of a larger issue. The way our global agriculture is developed is not sustainable, and we have to make the transition as soon as possible. Otherwise, the bee colony collapse disorder will be just another domino pieces, triggering many other negative changes after it.

Study Reference: Colony Loss 2014 – 2015: Preliminary Results.

buzzing airport

Airports all over the World are turning into Giant Bee Hives

Airports, some of the busiest places, are now becoming unlikely hosts for bees. Not content with mechanical winged contraptions, airports all over the world, from Germany to the US, are stepping up their sustainability game and installing apiaries. Next time you’re down the airport concourse to your gate, stop for a second and look outside. You might be in for a surprise!

Buzzing airports

buzzing airport

Beekeepers Bob Redmond, John Woodworth, and David Feinberg examine a hive at the SeaTac Airport in Washington. Photo © Rod Hatfield

Flying is not only costly for your pocket, but also to the environment.  It accounts for four to nine per cent of all global emissions – a disproportionate amount considering the number of people who fly versus those who drive, for instance. Low cost fairs and and an ever wealthier middle class coming out of developing countries mean there are more flights today than ever.  Since 1990, CO2 emissions from international aviation have increased 83 per cent. Recognizing the part they play in the man-made climate change framework, the industry has take steps to curb its emissions and overall carbon footprint. Some solutions include using more efficient engines or new fuels like biofuel/jetfuel mixes.

Airports themselves are also taking steps in reducing their carbon print. San Diego was the first US airport to adopt a formal sustainability policy back in 2008, and in 2012, the oceanside airport, became the first in the U.S. to install LEDs on its runways, guard lights, and airfield signs. Other airports focus their sustainable efforts on conservation, like LAX.  The airport has 307 acres of sand dunes voluntarily set aside as a nature preserve. Native plants and animals, including the delicate El Segundo Blue Butterfly (among the first insects put on the federal endangered species list back in 1976), are thriving again as part of this restoration project.

airport apiaries

Photo: Rod Hatfield

A popular trend among airports seems to be installing apiaries, odd as it may seem to some. The first to do so was  Hamburg Airport in Germany in 1999, quickly followed by Düsseldorf, Frankfurt, Dresden, Hannover, Leipzig/Halle, Nuremberg and Munich. Inspired by their success, other countries followed like  Malmo Airport in Sweden, Copenhagen, Chicago’s O’Hare, Seattle-Tacoma International and Lambert-St. Louis International.

airport apiaries

Photo: Rod Hatfield

Bees thrive in urban environments where there’s flower diversity and no pesticides. At the same time, urban spaces are crowded and bees are left with little room to mass a proper hive. That’s where airports come in – they have plenty of space.

airport apiaries

Photo: Rod Hatfield

In May 2011, the Chicago Department of Aviation (CDA) installed an apiary of 28 beehives at O’Hare. The project was managed by Brenda Palms Barber, the founder and chief executive of Sweet Beginnings, a nonprofit group that provides job training to men and women recently released from prison. Today, the apiary has expanded to 75 beehives which are home to over a million bees. It’s the largest apiary at any airport in the world and the first major on-airport apiary in the U.S. Each year, the O’Hare apiary makes thousands of pounds of honey which it process on site and distributes it at O’Hare in the Farmer’s Market in the Terminal 3 Rotunda. The honey you buy at the airport is really made there. Amazing!

airport apiaries

Photo: Rod Hatfield

In Europe, airports are also using the beehives as biological sensors. Pollen and honey are analyzed and used as biomarkers for pollution. Malmo airport first began to do this in 2009 and has since reported that each year levels of heavy metals, volatile organic hydrocarbons and polyaromatic hydrocarbons are well below European Union limits.

But is it a good idea to keep bees at airports? They seem to like it and mind little of the noise. In all events, the beehives are typical placed a few miles away from the runaway. Oddly enough, a Delta flight departing Pittsburgh International Airport for NYC was delayed after thousands of bees swarmed to the plane’s body. The buzzing critters bumrushed the craft’s wing just as the plane’s crew was preparing to fuel it. The Pittsburgh airport does not have in fact an apiary, and the bees likely came from some place nearby looking for a new nest.

airport apiaries

Photo: Rod Hatfield

While airport apiaries might have little impact per se, they do raise awareness on an already troubled populace. In the past couple of years, bees around the world have been dying in great numbers. Each year, on average, there are 30% less bees, with the rate dwindling a bit in recent years. Though not yet entirely certain, environmental factors like pesticides, disease or habitat loss have been attributed to the massive die off, called colony collapse disorder.

If you’d like to learn more, check our this interview Science Friday made with Bob Redmond, a beekeeper and director of The Common Acre, which manages the apiary at Sea-Tac airport in Washington State.

Neonicotinoid chemicals and bees

Pesticides threaten bees, birds and worms alike

A new study has shown that neurotoxic pesticides blamed for the huge drop in bee numbers are also equally affecting butterflies, worms, fish and birds.

Killing the Bees

Neonicotinoid chemicals and bees

Poor fellows! The decline of bees around the world is increasingly linked with neonicotinoid chemicals.

Analyzing two decades of research on the topic, they found out that two classes of pesticides – neonicotinoids and fipronil – show “clear evidence of harm”.

“We are witnessing a threat to the productivity of our natural and farmed environment,” said Jean-Marc Bonmatin of France’s National Centre for Scientific Research, co-author of the report entitled the Worldwide Integrated Assessment.

These nerve-targeting poisons are supposed to be protecting food security – but that’s really the opposite of what they’re doing in the long run. Bees are responsible for pollinating a huge amount of the global food, and these pesticides are “imperilling the pollinators, habitat engineers and natural pest controllers at the heart of a functioning ecosystem.”

In case you’re not aware, bee populations are dwindling. All around the world, bee populations are dropping more and more, and until recently, scientists still wasn’t sure why this was happening. Now, even though there isn’t a general consensus, there are very strong indications that it’s pesticides that trigger this drastic reduction in bee numbers. To make things even clearer, in countries which have banned these pesticides, bee numbers are starting to rise again.

More threats

But as huge as the bee damage is, other creatures are threatened just as much by the insecticides. As they seep into the underground or waters, neonics affect freshwater snails and water fleas, then birds, and finally fish, amphibians and certain microbes. They have also been linked with autism.

However, the most damage is done to terrestrial invertebrates such as earthworms. We don’t really think about earthworms, because, well, they’re not pretty, and most people don’t see them as useful – but that’s a shallow point of view. Earthworms are crucial in ecosystems, as they provide crucial soil-enrichment and aeration. With dropping worm populations, the local plants will be under even more stress, and the results will be devastating.

“The combination of their widescale use and inherent properties, has resulted in widespread contamination of agricultural soils, freshwater resources, wetlands, non-target vegetation, estuarine and coastal marine systems,” the authors wrote.

 

Insecticide is killing honeybees, causing colony collapse disorder

A Harvard study shows insecticides with neonicotionoids are devastating honeybee colonies, triggering colony collapse disorder.

Image via Wired.

Recently, we’ve written a lot about bees – because it’s a big deal. The National Agriculture Statistics Service reported that there were 2.44 million honey-producing hives in the United States as of February 2008, down from 4.5 million in 1980 – and it’s not much better in other parts of the world. Since three quarters of the world’s food require pollination, we’re talking about more than just bee populations. But it gets even worse: it’s also greatly affecting wild pollinators, and we still don’t know exactly why it’s happening (even though it’s pretty clear that we are the ones causing it, and there are some main suspects). Now, a new study from Harvard University claims to have figured out that problem, pointing to insecticides as the culprit.

“We demonstrated that neonicotinoids are highly likely to be responsible for triggering ‘colony collapse disorder’ in honeybee hives that were healthy prior to the arrival of winter,” said Chensheng Lu, an expert on environmental exposure biology at Harvard School of Public Health and who led the work.

Neonicotinoids are a class of neuro-active insecticides chemically similar to nicotine, and have been linked to damage caused to bees in insects for several years. Countries in the EU are already starting to ban the use of neonicotinoids, as the European Commission recommended a restriction of their use across the European Union but as usually, the US and Asia are lagging behind when it comes to environmental issues.

Connecting the dots

It was suspected for a long time that insecticides are directly connected with CCD, but due to the complexity of all the factors involved, it was pretty hard to directly connect the two. Now, researchers believe they’ve done that.

They monitored health of 18 bee colonies in three locations in central Massachusetts from October 2012 till April 2013. They treated two colonies with imidacloprid, two with clothianidin, and two were untreated control hives.

“Bees from six of the 12 neonicotinoid-treated colonies had abandoned their hives and were eventually dead with symptoms resembling CCD,” the team wrote. “However, we observed a complete opposite phenomenon in the control colonies.” Only one control colony was lost, the result of infection by the parasitic fungus Nosema and in this case the dead bees remained in the hive – this was not related to CCD.

This is a smoking gun for researchers, who were thrilled to report the findings.

“It is striking and perplexing to observe the empty neonicotinoid-treated colonies because honey bees normally do not abandon their hives during the winter,” the scientists wrote. “This observation may suggest the impairment of honey bee neurological functions, specifically memory, cognition, or behaviour, as the results from the chronic sub-lethal neonicotinoid exposure.”

So, the plan of action is simple (at least in the first stages) – stop using the damn neonicotinoid insecticides! They’re destroying bee populations. In European countries where this class of insecticides are banned, the cases of CCD have started to drop significantly, but in the UK, where the ban on neonicotinoids wasn’t implemented, CCD cases are peaking. The same goes for the US and China. After these substances are banned, we will probably see a stabilization of the bee (and wild pollinators) populations, and actually start thinking about how to regrow these populations. The solution is simple – we just have to do it.

Scientific Reference: Sub-lethal exposure to neonicotinoids impaired honey bees winterization before proceeding to colony collapse disorder.

Photo of small native bee species Andrena bradleyi on a highbush blueberry flower. Click to enlarge. (Photo credit: Hannah Burrack.)

Measuring how effective certain insects are at pollinating

We’ve written extensively about the impending global disaster triggered by the crippling of bee populations worldwide at the hand of Colony Collapse Disorder (CCD). Just recently, I wrote an article discussing the findings of a new paper that suggests the leading factors that cause CCD are most complex than previously thought – namely, a whole brew of pesticides and fungicides have been found to dramatically alter bee colonies. Now, North Carolina State University are proposing a set of guidelines for assessing the performance of pollinator species in order to determine which species are most important and should be prioritized for protection.

Photo of small native bee species Andrena bradleyi on a highbush blueberry flower. Click to enlarge. (Photo credit: Hannah Burrack.)

Photo of small native bee species Andrena bradleyi on a highbush blueberry flower. Click to enlarge. (Photo credit: Hannah Burrack.)

Whether we’re talking about flowers, vegetables or crops most of the pollinating is made by insect species. Clearly, insects play a key role in the biosphere, and the dramatic downfall of some of these pollinating species, namely bees, poses a dramatic threat to both plant life and the food chain. Which species are the best pollinators, though? This question may be important to answer to foster conservation efforts and better distribute resources to where they’re most needed or where these can be used most effectively.

“Widespread concerns over the fate of honey bees and other pollinators have led to increased efforts to understand which species are the most effective pollinators, since this has huge ramifications for the agriculture industry,” says Dr. Hannah Burrack, an associate professor of entomology at NC State and co-author of a paper on the new guidelines and related research. “However, various research efforts have taken a wide variety of approaches, making it difficult to compare results in a meaningful way.

“We’ve developed a set of metrics that we think offers a comprehensive overview of pollination efficiency, which would allow researchers to compare data from different crops and regions.”

The NC State study looked at four primary metrics when assessing pollinating capabilities of species.

  • Number of seeds produced for one flower.
  • Abundance, which measures the number of each type of bee observed in the area.
  • Weather behavior: how active is the bee species during various weather conditions (cold, cloudy, windy etc.)
  • Visitation rate: number of flowers visit function of the amount of time spent at each flower.

There’s no such thing as a perfect bee, apparently

 “The perfect bee would produce a lot of seeds and visit a lot of flowers, even in poor weather – and there would be a lot of them,” Burrack says. “But as far as we know, the perfect bee doesn’t exist.”

I pilot study was made at a site made up of  highbush blueberry crops in North Carolina. Small native bees had extremely high single-visit efficiency rates and were active during inclement weather, however it also found that th3se  did not have high abundance nor appear to have high visitation rates.

“This highlights the importance of incorporating multiple metrics,” says Dr. David Tarpy, an associate professor of entomology at NC State and co-author of the paper. “Because researchers looking only at visitation rates or abundance may think the small native species are unimportant, when they actually appear to be important pollinators for blueberry growers.”

It’s possible that using these metrics, scientists can make a pollinating species effectiveness measure for their own local ecosystem, and thus have a broader picture. By measuring these key metrics, it may be possible also to assess how pesticides or lack of them influence these metrics.

The findings were reported in a paper published in the journal  Environmental Entomology.

Italian ban on pesticides has major benefits on bee health

chemicals

In case you didn’t know, bee popullations all around the world are dwindling. The disorder which is causing this massive decline in bee numbers is called CCD – colony collapse disorder. In 2012 alone, a phenomenon called colony collapse disorder (CCD) wiped out about half of honeybee hives [read more here]. What happens in CCD is that basically worker bees go away from the hive and never return; it’s not yet clear why this happens and what are the exat causes, but there is a strong link with the more intensive use of pesticides.

The pesticide industry is huge however, and, naturally, they started voicing skepticism about this – things reached a critical level when Italy announced the ban on some pesticides last year. But the ban passed, a year passed after it, and now we see the results.

bee2

The status of the bee popullations has improved dramatically. Francesco Panella, President of the Italian Association of Beekepers, says:

On behalf of beegrowers working in a countryside dominated by maize crops, I wrote to the Minister of Agriculture to confirm the great news, for once: thanks to the suspension of the bee-killing seed coating, the hives in the Po Valley are flourishing again. We cannot underestimate that there are over one million hectares of maize crops, predominantly in Northern Italy, which means one crop out of every seven which are grown every year in our country. This year’s magnificent and unusual spring growth of bee colonies means a very good production of acacia honey in Northern Italy. We are now anxious to ensure that the temporary ban of neonicotinoid seed coating becomes definitive

There have been three papers on the matter, each detailing a different type of pesticide, though none of them are peer reviewed. However, Marco Lodesani, director of the honey bee and silkworm unit at the Agricultural Research Council (CRA-API) in Bologna, elaborates:

What did we learn in the past few years about the causes of CCD and the link with neonicotinoids?

Until recently, studies focused on the immediate, lethal effects of pesticides on bees. In other words, they looked at the dose that is needed to kill bees if they are exposed to a certain insecticide.

However, it is now clear that sub-lethal doses have a chronic effect that may be even more critical. When bees fly over the dust from coated seeds, they accumulate small doses of neonicotinoids that do not kill them. But it affects both each individual and the colonies in more subtle, long-term ways. For example, contaminated bees have a weaker immune response. This makes them more susceptible to viruses, which are a major cause of death.

Other effects are neurological and include learning problems, impaired orientation, or the inability to remember colours and odours. All of these aspects are crucial for the social organisation of colonies.

Are these chronic effect taken into account by the industry when testing for the safety of new compounds?

Not really. Testing is largely based on assays that look at the acute toxicity of compounds. But with CCD you do not necessarily expect to see bees decimated right in places where they use pesticides. You need to look at sub-lethal effects that are more insidious and difficult to study, but still involve entire colonies.

Via Planet3