Researchers develop a fungus that kills mites that contribute to honey bee Colony Collapse Disorder.
- Honeybee colony collapse is due in part to Varroa mites that weaken honey bee immune systems.
- Chemicals that were once effective against the mites are no longer working as well.
- Researchers are stepping in with a newly cultured fungus that goes after the mites without bothering the bees.
Honey bees are vitally important to agriculture — by some estimates, they're responsible for pollinating more than 80 crops, adding up to about one third of the crops that we eat. The USDA says they add at least $15 billion of value annually to U.S. crops in the form of higher yields and increased harvest quality. Humanity has a vested interest in helping to maintain healthy honeybee populations.
One problem for honeybees is a phenomenon known as Colony Collapse Disorder (CCD), which was first identified in 2006. With CCD, all adult bees in a hive die, leaving behind a queen, some immature bees, and honey. According to entomologist Sammy Ramsey, bees remain under pressure from what he calls the three Ps: parasites, pesticides, and poor nutrition.
Varroa destructor mites are a big part of that first P. They feed on bees — sucking fat from their bodies — leaving them with weakened immune systems that make the bees more susceptible to disease. Now entomologists at Washington State University (WSU) have developed a new strain of a mold-like fungus, Metarhizium, that can eradicate the mites. It does so without miticides, chemicals against which the mites are becoming increasingly resistant. The team's study is published in Scientific Reports.
Metarhizium made for the hive environment
Metarhizium killing varroa timelapse youtu.be
According to author Steve Sheppard of WSU's Department of Entomology, "We've known that metarhizium could kill mites, but it was expensive and didn't last long because the fungi died in the hive heat." The team's innovation was breeding a strain that can thrive in a hive. "Our team used directed evolution to develop a strain that survives at the higher temperatures."
There should be no safety issues introducing Metarhizium into a colony as bees are highly resistant to its spores. When Metarhizium encounters a mite, it drills into it before proliferating and killing the mite from the inside, as shown above.
As they cultured their Metarhizium, the researchers screened over 27,000 mites to identify the most deadly variants. "It was two solid years of work, plus some preliminary effort," says lead author Jennifer Han. When they arrived at their final Metarhizium, "We did real-world testing to make sure it would work in the field, not just in a lab."
Not their first fungus
The new strain of Metarhizium is the second agent the researchers have developed to aid bee colonies. In 2018, they announced the development of a mycelium extract that reduced virus levels in bees.
Together with their earlier invention, fungus expert Paul Stamets says the team has put together "a real one-two punch, using two different fungi to help bees fight varroa. The extracts help bee immune systems reduce virus counts while the metarhizium is a potentially great mite biocontrol agent."
(Star Trek Discovery fans may note that the crew member who interacts with a universal mycelial network is named… "Paul Stamets.")
Two things have to happen now before WSU's Metarhizium can be released to agricultural hives. First, the team has to nail down the optimal steps by which beekeepers can introduce the fungus to their bee colonies. Second, the Environmental Protection Agency has to approve Metarhizium for use.
It's time to rethink how satellites and other objects are made and eventually destroyed.
- The objects humans send to space teach us a lot about the universe, but they are also cluttering it up. While some objects are close enough to be retrieved, others become dangerous, fast-moving bullets that can cause serious damage.
- In addition to cleaning up what's already there, MIT Assistant Professor Danielle Wood says that we need to think more sustainably about the technology used in future missions. "We have to ask the question, will we respect the rights of people and the environment as we go forward in space," Wood says.
- One possible solution is a wax-based fuel source (made of beeswax and candle wax) for satellites that would be less toxic and more affordable than currently used inorganic compounds, and that would help bring the objects closer to Earth for deorbiting and destruction.
First picture of worldwide bee distribution fills knowledge gaps and may help protect species.
Twelve different species of bees swarming a flowery meadow. Etching by J. Bishop, after J. Stewart.
Credit: Wellcome Collection, CC BY 4.0
How many bee species are there? Wait a minute: honeybee, bumble bee, erhm… five? Five hundred? Five thousand? Not even close: the total is well over 20,000 – which means there are more species of bees than of birds and mammals combined.
There's no shame (nor surprise) for bee civilians like you or me in not knowing that. What is surprising, is that even scientists who specialise in bees didn't quite know how those species are distributed all over the world. Until now.
By combining and filtering more than 5.8 million public records of bee occurrences, a team of researchers from China, the U.S., and Singapore have built up the very first comprehensive picture of bee diversity worldwide. And that picture presents a few surprises, both for laypersons and specialists.
Bee ignoramuses will be surprised to learn that the United States is the throbbing heart of bee diversity. The U.S. has far more bee species than any other region on Earth. And by the fact that large tracts of Africa and the Middle East remain terra incognita, in terms of apiary diversity.
Relative bee species richness in the New World. Note the low density in the Amazon Basin.
Credit: Current Biology, open access
In general, there are more bee species in the Northern Hemisphere than the Southern and—confirming previous hypotheses–more in arid and temperate climates than in the tropics.
That goes against the common pattern in biology known as the 'latitudinal gradient', which predicts that species diversity (of most plants and animals) increases towards the tropics and decreases towards the poles. Bees are an exception, with a higher species concentration away from the poles (in what scientists call a 'bimodal latitudinal gradient').
To give that difference some visual immediacy, imagine a graph with one hump in the middle (i.e. the latitudinal gradient) versus one with two humps, one on either side of the middle (i.e. the bimodal latitudinal gradient). In other words: dromedary (one-hump) versus camel (two-hump).
It seems counter-intuitive that bees would thrive better in arid deserts than in lush tropical jungles; but that's because trees–the dominant vegetation type in the tropics–provide less bee food than the plants and flowers that grow elsewhere.
Three ways of measuring species richness in the Americas: (A) richness of polygons, (B) sPCA and (c ) turnover. All suggest a large, distinct bee fauna in the southwestern U.S.
Credit: Current Biology, open access
Also, bees don't like it too wet, unlike their cousins the ants, whose populations peak in the humid tropics. The researchers think humidity may play a role in limiting bee distribution by spoiling pollen resources.
The relative absence of bees from the tropics has consequences for pollination, which in those regions is performed by a wide variety of alternative species: wasps, moths, and even cockroaches.
Previous datasets of global bee distribution were either inaccurate, incomplete, or difficult to interpret. This world map clearly establishes that bees prefer dry and temperate zones to wet and tropical ones. For bee scientists, it provides a much-needed baseline to predict the geographic distribution of bees and interpret the relative richness of species.
While much work needs to be done to fill additional knowledge gaps, this baseline is an excellent starting point, not just for greater understanding, but also for better conservation. Because bees are not just for making honey. In many countries, they're the top pollinator species. And they typically visit 90 percent of the leading crop types.
Carpenter bee (Xylocopa latipes) pollinating a flower in the Indian state of Kerala.
Yet over the past decades, bee populations have been crashing. In the U.S., honeybee populations have declined by 60 percent between 1948 and 2008. In Europe, 12 wild bee species are critically endangered.
That trend is potentially disastrous for agriculture. More than $550 billion in annual global crops are at risk from pollinator loss. The loss of bees as pollinators would lead to a collapse in crop yields and even entire ecosystems.
Better understanding bees increases our options for protecting them. This study will help pinpoint bee diversity hotspots in otherwise poorly examined parts of the world and help predict how bees will react to climate change–for example when certain regions will get wetter weather.
Protecting bee diversity is especially important and urgent in developing countries, where many of the knowledge gaps are located, and where many crops rely on native bee species for pollination.
Strange Maps #1060
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An active component of honeybee venom rapidly killed two particularly aggressive forms of breast cancer in a laboratory study.
- New laboratory studies by a team of scientists found that the active component of honeybee venom induced death in two forms of malignant breast cancer cells that are notoriously difficult to treat.
- The magic healing molecule in the honeybees' venom appears to be melittin, which rapidly killed cancer cells in under an hour.
- In the future, doctors could potentially use melittin alongside chemotherapy drugs to increase the efficacy of the treatment.
Since ancient times, the honeybee's (Apis mellifera) honey has been hailed for its medicinal properties. Now, scientists are discovering the miraculous healing potential of its sting in curing cancer. New laboratory studies by a team of Australian researchers have found that the active component of honeybee venom, melittin, rapidly killed two forms of malignant breast cancer cells that are notoriously difficult to treat while leaving healthy cells unharmed.
The magic molecule
Previously, honeybee venom has shown potential in treating other medical conditions such as eczema and tumors, and it has been known to have anticancer properties. How the venom works against tumors on a molecular level hasn't been understood, but science just got a lot closer.
It seems that the magic healing ingredient in the honeybees' venom is melittin — the zingy molecule responsible for producing the painful sting of a bee. Scientists at the Harry Perkins Institute of Medical Research in Perth, Australia and the University of Western Australia found that the melittin induced cancer cell death.
Their lab study, reported in the journal NPJ Precision Oncology, is the first to have looked into the effect the ingredient has on a range of breast cancers, the most common cancer in women worldwide. The two most aggressive and hard-to-treat types are known as triple-negative breast cancer (TNBC) and HER2-enriched breast cancer, which tend to mutate to resist existing treatments. The researchers found that melittin rapidly kills these cancer types and, critically, does so with no negative effects on normal cells.
"The venom was extremely potent," said research leader Ciara Duffy from The Harry Perkins Institute of Medical Research in a news release. "We found that melittin can completely destroy cancer cell membranes within 60 minutes."
The lab study also found that bumblebee venom (which does not contain melittin) did not kill those particular breast cancer cells.
How it works
Melittin disarms cancer cells by puncturing holes in their outer membrane. Another stunning effect: within just 20 minutes of exposure to melittin, the chemical messages cancer cells need to grow and divide are disrupted.
"We looked at how honeybee venom and melittin affect the cancer signaling pathways, the chemical messages that are fundamental for cancer cell growth and reproduction, and we found that very quickly these signaling pathways were shut down," said Duffy.
The molecule is able to do this by stopping the activation of receptors that signal growth factors in the cells' membranes. The large number of these receptors in HER2-enriched cancer cells and some TNBC cells is one reason for their uncontrollable growth. Melittin seems to halt the cell's proliferation by blocking those growth signals from getting through.
"Significantly, this study demonstrates how melittin interferes with signalling pathways within breast cancer cells to reduce cell replication," said Western Australia's Chief Scientist Professor Peter Klinken. "It provides another wonderful example of where compounds in nature can be used to treat human diseases."
Enhancing current cancer treatments
The team also tested to see if melittin could be used with existing chemotherapy drugs, as the pores in the membranes that it creates may allow other treatments to faster penetrate and kill cancer cells.
They tested the idea on a lab mouse with triple-negative breast cancer. They injected it with a combination of melittin and docetaxel — a drug used to treat a number of cancers including breast cancer. The mixture proved to be more effective at shrinking the tumors than either melittin or docetaxel alone.
In the future, doctors could potentially use melittin alongside chemotherapy drugs to enhance the efficacy of the treatment. This may allow them to reduce the dosage of chemotherapy drugs, and the adverse side effects that come with it.
The authors in the study point out that honeybee venom is inexpensive and easy to obtain, thus making it a fantastic option for cancer treatment in regions and countries with poorly resourced health services and care.
"Honeybee venom is available globally and offers cost effective and easily accessible treatment options in remote or less developed regions," the authors write. "Further research will be required to assess whether the venom of some genotypes of bees has more potent or specific anticancer activities, which could then be exploited."
Though exciting, this research is still in early, lab testing stages. The researchers will still need to perform clinical trials to assess the safety and efficacy of melittin for treating breast cancer in humans.
Declining bee populations could lead to increased food insecurity and economic losses in the billions.
Bees have endured a disastrous half-century. In the winter of 2018, U.S. beekeepers reported losing 37.7 percent of their honeybee colonies. It was the largest die-off reported since the Bee Informed Partnership began its survey in 2006, yet in that decade, average winter losses of managed colonies were 28.7 percent. That's near twice the historic rate and part of a 50-year trend of declining species richness in wild bees and other pollinators.
That's bad news for the bees and also anyone who depends on the food generated through their labor. That is, all of us. According to the USDA, approximately 35 percent of the world's food crops depend on animal pollinators to reproduce, with some scientists estimating that "one out of every three bites of food we eat exists because of animal pollinators."
That many crops depend on pollination to reproduce is well-established; however, how much pollination proves a limiting factor to crop yield is less understood. If wild bee and managed honeybee populations continue to decline, will the amount of food available to feed us decline, too? That's the question a Rutgers-led team of researchers sought to answer.
From bee to farm to table
A bar graph showing the percentage of pollination limitation for the seven crops studied.
The research team selected seven crops to study: apples, almonds, pumpkins, watermelons, sweet cherries, tart cherries, and highbush blueberries. These were chosen because each is highly dependent on insect pollination for reproduction. The researchers then established a nationwide study across 131 U.S. and British Columbia farms. They selected only commercial farms in top-producing states—for example, Michigan and Oregon farms for blueberries. This way, their sample would represent the conditions and farming practices in which a majority of these crops are grown.
After collecting data on pollinator visitation rates and crop production, the researchers measured the data through three statistical models. They also analyzed the contribution differences between wild bees and managed honeybees as well as the economic value of the bees' service.
"We found that many crops are pollination-limited, meaning crop production would be higher if crop flowers received more pollination. We also found that honey bees and wild bees provided similar amounts of pollination overall," Rachael Winfree, a professor in the Department of Ecology, Evolution, and Natural Resources at Rutgers University-New Brunswick and the study's senior author, said in a release. "Managing habitat for native bee species [and] stocking more honey bees would boost pollination levels and could increase crop production."
Of the crops studied, apples, blueberries, sweet cherries, and tart cherries were hit hardest when pollination decreased. Watermelon and pumpkin yields weren't as limited by pollinators, possibly because these crops sport fewer blooms and flower in summer when the weather is less inclement. Almonds proved the outlier as the crop is the earliest bloomer yet not pollination limited. The researchers speculate that this is due to the almond industry's intense reliance on managed honeybees.
"Our findings show that pollinator declines could translate directly into decreased yields or production for most of the crops studied, and that wild species contribute substantially to pollination of most study crops in major crop-producing regions," the researchers write.
For the seven crops studied, the researchers estimate the annual production value of pollinators to be more than $1.5 billion. They also found that wild bee species provided comparable pollination, even for crops in agriculturally intensive regions.
Their findings were published in the most recent Proceedings of the Royal Society B: Biological Sciences.
Ecological and edible incentives
A protester shows a handful of bees that died by pesticides. The protest was held during the Bayer AG shareholder meeting in 2019.
(PhooMaja Hitiji/Getty Images)
The concern extends beyond these seven. Crops such as coffee, avocados, lemons, limes, and oranges are also highly dependent on pollinators and may prove pollination limited. If declining bee populations are tied to such yields, it could mean barer supermarket shelves and increased prices. While that may only be an annoyance to some, to poor and vulnerable communities who already struggle to secure salubrious, affordable food, such a deficit would present another barrier to the vital micronutrients necessary for a healthy life and diet.
Unfortunately, the threats to bees are numerous. Parasites, agrochemicals, monoculture farming, and habitat degradation all play a role, and neither stressor works in isolation. Sublethal exposure to neonicotinoids, an insecticide, can cause impairments in bees, while monoculture farming serves up a monotonous and unhealthy floral buffet. Both impede bees' immune systems, rendering them vulnerable to parasites such as Varroa destructor, a mite that can transmit debilitating viruses as it feeds on bees' fat bodies. And all of these stressors will likely be inflamed by climate change in the years to come.
Some have proffered mechanical solutions, such as Japan's National Institute of Advanced Industrial Science and Technology where technicians are developing robotic bees. These micro-drones are covered in gelled horsehair and have successfully cross-pollinated Japanese lilies. Other experiments include pollen sprays. However, the large-scale viability of tech-centric solutions seems questionable. After all, wild bees currently perform their ecological services pro bono and are as effective as managed honeybees. Any technological solution implemented in their absence would add to the agricultural costs and likely increase prices anyway.
Ecological amelioration will be necessary. To combat habitat fragmentation and strengthen biodiversity, many cities are implementing green-way strategies. For example, the Dutch city of Utrecht has decked its bus stop roofs with plants and grasses to create bee and butterfly shelters, while other cities are looking to foster bee-friend roadsides. And government initiatives incentivize farmers and landowners to adopt bee-friendly management practices. These solutions aren't only a matter of ecological conservation but also food security and public health.