Tag Archives: bumblebee

Bumblebees apparently headed towards mass extinction

In a single human generation, the chances of a bumblebee population surviving in any given place has decreased by more than 30%.

Flowers — yum! Extreme heat? Not so much. Image credits: Carolien van Oijen.

It’s never easy to pinpoint the causes of a generalized problem. Bees have been struggling all around the world, and it’s likely due to several factors. Take, for instance, urbanization — the fragmentation and destruction of habitats has taken a massive toll on bees, and the flowers we plant in urban areas are often not the ones bees need to survive. Agricultural fields can also have a detrimental effect, and pesticides have been shown time and time again to be devastating for pollinator populations.

Furthermore, on top of all these stress factors, there is a surge of a dangerous bee parasite: the Varroa mite, which carries up to 18 debilitating bee viruses to which bees are virtually defenseless. There is, on top of all of this, another major threat to bees.

I’m talking, of course, about climate change.

Too hot to buzz

The study analyzed data from 66 bumblebee species across North America and Europe over a period of 115 years, testing how extreme heat affects bee species. The study was carefully designed to avoid the effect of changing land use.

Climate change-related change in bumblebee species richness from a baseline (1901–1974) to a recent period (2000–2014). Very few areas did not experience losses. Image credits: Soroye et al (2020) / Science.

They then developed a model simulating “climate chaos” scenarios, comparing how the bumblebee populations had moved over the years in response to rising temperatures. They found that bumblebee populations were indeed decreasing in accordance to how much temperatures were rising. Extreme heat, in particular, was devastating to these populations, as it exceeds the bees’ tolerance.

Bumblebees, a crucial pollinator, are already in a well-documented decline. This shows that climate change is a main driver of decline for bumblebees, which suggests that the insects might be heading for a mass extinction as temperatures continue to rise.

“Mitigating climate change–driven extinction risk among bumblebees requires efforts to manage habitats to reduce exposure to the growing frequency of temperatures that are extreme relative to species’ historical tolerances,” the researchers write in the study.

The authors’ concern was shared by other scientists. Jonathan Bridle and Alexandra van Rensburg of the University of Bristol described the findings as “alarming” in their commentary for the journal Science:

“The new study adds to a growing body of evidence for alarming, widespread losses of biodiversity and for rates of global change that now exceed the critical limits of ecosystem resilience.”

Ultimately, the researchers conclude, there’s no quick fix to this. If we want to stop this environmental disaster (and the massive economic losses associated with it), we’d better focus on reducing our greenhouse gas emissions.

Bumblebees carry heavy loads in ‘economy’ flight mode

Bumblebees can carry surprisingly heavy loads of nectar, a new paper explains, potentially bearing up to their own body weight in the sweet liquid. Furthermore, the insects use a more energy-efficient flight pattern when heavily encumbered.

Image credits Suzanne Williams.

The humble bumblebees definitely lift, the authors report. In fact, they may be the ‘big lifters’ of the insect world. The team set out to understand how the bumblebees manage to fly with such impressive loads, and uncovered the surprising flexibility and adaptability of their flight mechanics.

The burdens we bear

“[Bumblebees] can carry 60, 70, or 80 percent of their body weight flying, which would be a huge load for us just walking around,” said Susan Gagliardi, a research associate in the College of Biological Sciences at the University of California (UoC) Davis and co-author of the paper.

“We were curious to see how they do it and how much it costs them to carry food and supplies back to the hive.”

For the study, the team emptied a snowglobe (to be used as an experimental chamber) and released bumblebees inside it. Each insect had various lengths of solder wide attached to it in an effort to adjust its weight. High-speed video cameras were used to record their wing beats and movements, while the team charted how much energy each bee needed to expend.

“We have the bees in a little chamber and we measure the carbon dioxide they produce. They are mostly burning sugar so you can tell directly how much sugar they are using as they are flying,” Gagliardi said.

Unlike our aircraft, which generate lift from the smooth flow of air over their fixed, horizontal wings, bees move their wings at a high angle to generate tiny wind vortices. These churning bodies of air curl around the insect’s wings and lift them up. The team explains that while the bee’s approach does generate more lift than the smooth-airflow approach out planes rely on, it’s also more unstable mechanically — the vortices are chaotic and they break down very quickly. Bees are only able to fly because they move their wings rapidly to re-generate the vortices.

We didn’t know, however, the energy-efficiency of this mode of flight. It seems reasonable to assume that the bees would use less energy the lighter their load is, but the team was surprised to find out this isn’t the case: bumblebees are actually more efficient per unit of weight when they’re heavily laden. In other words, they’re more “economical in flying” when they’re heavily loaded — “which doesn’t make any sense in terms of energetics,” says Stacey Combes. Combes is an associate professor in the Department of Neurobiology, Physiology, and Behavior at the UoC and the paper’s lead author.

The team explains that bumblebees have two ways to deal with heavy loads. They can either increase the amplitude of their strokes (i.e. how far the wings flap), which helps but isn’t enough on its own for the heaviest of loads, or increase the frequency of their wingbeats, which helps them stay aloft but costs more energy. However, they also observed an alternative flying mode being used — one the team calls their “economy mode” — in which the bees can carry lots of nectar while using less energy than faster flapping requires.

Exactly how they do this is still unclear, Combes said, although the team believes it may involve the wings rotating when reversing direction between strokes. However, it seems to be something that the bees themselves can choose to do, or not. The team explains that overall, when lightly-loaded or rested, the bumblebees were more likely to increase the frequency of their wingbeats. However, they switch to the ‘economy mode’ only when heavily loaded, which produces more lift without an increase in flapping frequency.

“It turns out to be a behavioral choice they are making in terms of how they support the load,” Combes said.

But why don’t they always fly in this mode? The team is still unsure, but it may be that high wingbeat frequency brings other advantages to the table that are more attractive to the bees in a lighter-load scenario.

“When I started in this field there was a tendency to see them as little machines, we thought they’ll flap their wings one way when carrying zero load, another way when they’re carrying 50 percent load and every bee will do it the same way every time,” Combes adds.

“This has given us an appreciation that it’s a behavior, they choose what to do. Even the same bee on a different day will pick a new way to flap its wings.”

The paper “Kinematic flexibility allows bumblebees to increase energetic efficiency when carrying heavy loads” has been published in the journal Science Advances.

Want to save the bumblebees? See what plants they like

Some plants make the bees go “yum” — let’s plant more of those.

By now, it’s no secret that bee numbers are dwindling. All around the world, these key pollinators struggling. The reasons are not entirely clear, but the increased use of pesticides plays a key role, as does habitat fragmentation by urbanization and intensive farming.

Another factor contributing to the decline of bees is the lack of flowers — or rather, the lack of flowers that bees like. Many urban gardens that look aesthetically pleasing and are carefully managed provide little support to bees, as pretty flowers aren’t necessarily what the bees like. Meanwhile, some meadow flowers (which might even be regarded as weeds) are godsent. To put it simply, bees don’t really like all flowers equally.

In a new study, researchers wanted to see what flowers bumblebees in California prefer. Identifying these preferences could help manage and restore meadows, gardens, and other habitats in a way that favors the development of bumblebees.

Researchers captured and released bumblebees at over 400 sample plots in the Plumas National Forest, recording which flower the bees were captured on.

The study also considered the availability of each plant to the bees, in addition to the exhibited preference.

“It’s important to consider the availability of plants when determining what’s selected for by bees,” says Jerry Cole, a biologist with The Institute for Bird Populations and lead author of the study. “Often studies will use the proportion of captures on a plant species alone to determine which plants are most important to bees. Without comparison to how available those plants are, you might think a plant is preferentially selected by bees, when it is simply very abundant.”

Thirteen different bumblebee species were analyzed. The big winner was A. urticifolia, a flowering plant in the mint family. This plant was most strongly selected by three species.

However, some previously unknown associations were also found. For instance, a bumblebee known as the two-form bumble bee (Bombus bifarius) seemed to prefer aster flowers (Eurybia integrifolia), while the black tail bumble bee (Bombus melanopygus) was spotted selecting Rydberg’s penstemon flowers (Penstemon rydbergii). The bees’ preference also varied depending on the time of year (some flowers were preferred more in the summer, others in the autumn).

“We discovered plants that were big winners for all bumble bee species but, just as importantly, plant species that were very important for only a single bumble bee species,” says Helen Loffland, a meadow species specialist with The Institute for Bird Populations. “This study allowed us to provide a concise, scientifically based list of important plant species to use in habitat restoration that will meet the needs of multiple bumble bee species and provide blooms across the entire annual lifecycle.”

It’s heartening to note that the results of the study are already being put to use. Planning carried out in the Plumas is considering the best flowers to expand and improve bumble bee habitats, says co-author Matthew Johnson. In addition, Forest Service personnel has also collected seed from plants, experimenting with the best way to use them in seed mixes. Researchers also want to involve high school students in this project.

This is just a step towards improving bee conservation, but a better understanding of their flower preference can help declining species in both urban and rural areas — with very little costs.

“This sort of knowledge can really increase the effectiveness of restoration for bumble bees,” says Loffland, “and in a way that is relatively easy and cost-effective to implement.”

Most countries have some NGO or conservation groups working with bees. If you’re interested in seeing what works best in your area, contact them. Many such groups even send free seed packages to use in your garden, to help support your local bee community.

Queen bumblebees take long breaks in the grass after hibernating

Scientists working in the UK have discovered a previously unknown behavior of queen bumblebees: they spend the majority of time hiding in the grass before starting a new colony.

Bumblebee queens spend a lot of time resting on the ground, researchers say. Image via Wiki Commons.

There are over 250 species of bumblebees, and most of them are social insects, forming colonies and relying on a single queen to produce offspring — as well as new queens, for new colonies. However, not much is known about queen behavior after it emerges from winter hibernation.

In order to address this, a team of researchers from the Queen Mary University of London placed small radar antennas on the backs of queens that had just emerged from artificially-induced hibernation, to see what these queens would do after emerging. The antennas were small enough to not impede the movements of the bees but allowed researchers to trace them.

Dr. James Makinson, who co-led the study, said:

“We wanted to see what queens actually do right after they emerge. By combining state-of-the-art tracking technology with wild bee observations, we were able to uncover a never before seen behavior of queen bumblebees.”

During the winter, queen bumblebees hibernate in the ground and when spring comes, they start looking for a suitable site for a nest. The traditional idea was that after hibernating, the queens start feeding and disperse quickly to find a new colony. But results contradicted this theory.

Queen bumblebee with an attached antenna. Image credits: James Makinson.

The radar data showed that the queens were spending most of the time on the ground. They would fly for 10-20 seconds in seemingly random directions and then spend 10-20 minutes on the ground, resting. This pattern was confirmed by observations on wild queen bumblebees.

Researchers then carried out computer models of this behavior, finding that it can explain how the queens end up starting a colony kilometers away from their hibernation site. Dr. Joe Woodgate, a co-lead author, said:

“Our study suggests that a few weeks of this type of behaviour would carry queen bees several kilometers away from their hibernation site and might explain how queens disperse from the nest in which they were born to the place they choose to found a new colony.”

“Better understanding the behavior of queens during this crucial period of their lives can suggest practices to improve their chances of successfully founding new colonies and help their survival,” he adds.

The dispersal of animals from their birth place has profound effects on the immediate survival and longer-term persistence of populations, researchers write, and this study is particularly important as bees all around the world are facing a steep decline, with no clear solution in sight. Plating bee-friendly plants in urban areas can provide much-needed oases for bees, and now, this study suggests that “green corridors” could further help them.

“Our findings suggest that creating pollinator friendly corridors between conserved landscape patches would be helpful. It would also be beneficial to plant pollinator friendly flowers and trees all year round, giving bumblebee queens ample access to food during their early spring emergence. And leaving vegetation, such as leaf litter and long grass, undisturbed until late in the spring would give queen bumblebees safe places to rest,” adds Makinson.

If you see an exhausted queen bee on the ground, researchers suggest that you can rescue her by providing a teaspoon of sugary water (half water, half sugar, stirred). Simply put the solution on a teaspoon and place it gently near her antennae or mouth-parts, and then giving her time to drink it. The solution could give the bee that extra drop of energy she needs to be able to fly on its own and ultimately start a new colony. This small gesture could do a lot of good.

Image credits: David Attenborough.

Journal Reference: ‘Harmonic radar tracking reveals random dispersal pattern of bumblebee (Bombus terrestris) queens after hibernation’. Makinson et al. Scientific ReportsDOI: 10.1038/s41598-019-40355-6


New sensor backpacks could turn bees into crop-monitoring drones

Drones? No thank you — I prefer backpacking bees.


Image credits Suzanne D. Williams.

Engineers from the University of Washington (UW) plans to give farmers a powerful (and adorable) alternative to drones. The team has developed tiny sensor systems that can fit on the back of a bumblebee without restricting the insects’ ability to fly. Such a package only requires a tiny battery to operate for up to seven hours at a time, and can recharge while the bees sleep in their hive at night.

BEElievable readings

“Drones can fly for maybe 10 or 20 minutes before they need to charge again, whereas our bees can collect data for hours,” said senior author Shyam Gollakota, an associate professor in the UW’s Paul G. Allen School of Computer Science & Engineering.

“We showed for the first time that it’s possible to actually do all this computation and sensing using insects in lieu of drones.”

It’s not the first time researchers have thought of ‘sensorising’ bees. The insects have one massive advantage over drones: they fly on their own power. However, they can’t carry much weight, limiting the range of sensors they can be fitted with. This also makes GPS receivers (which require a lot of energy and, thus, heavy batteries, to run) completely out of the question. Because of that, the farthest researchers have ever gotten was to superglue simple RFID (radio-frequency identification) backpacks onto bees to follow their movement. However, such RFID packs were a proof-of-concept and of limited use — they only worked for distances of about 10 inches and didn’t carry any sensing equipment.

The UW team needed sensors that were able to both accurately tell their location and fit on the tiny backs of bees for this research to pan out. They decided on using bumblebees (genus Bombus) since they’re beefier and can handle the weight of a tiny battery, says co-author Vikram Iyer, a doctoral student at the UW. These batteries, while small, could power an array of sensors for much longer than a conventional drone could be kept operational. Furthermore, they can be wirelessly recharged every night when the bees go to sleep.

The backpack they developed weighs only 102 milligrams, which the team says is roughly the weight of seven grains of uncooked rice. Bees are placed in a cold environment for a short while to slow them down, and the packs are glued to their back. The researchers used a similar method to remove the packs.

“The rechargeable battery powering the backpack weighs about 70 milligrams, so we had a little over 30 milligrams left for everything else, like the sensors and the localization system to track the insect’s position,” said co-author Rajalakshmi Nandakumar, a doctoral student in the Allen School.

Because GPS receivers weren’t a viable option, the team developed a unique method of localizing the backpack-toting bees. They set up multiple antennas, each broadcasting signals from a base station across a specific area. A receiver installed in the backpacks could pick up on the intensity and direction of the incoming signal to triangulate its position in space.

The team tested their localization system by installing four antennas on one side of a soccer field and carried a bee-with-backpack around the field in a jar. As long as they stood within 80 meters (roughly three-quarters the length of a soccer field) of the antennas, their system could accurately triangulate the bee’s position.

Small sensors monitoring temperature, humidity, and light intensity were later added to the pack. These would allow bees to collect and log data (along with their location) as they buzzed around the farm.

“It would be interesting to see if the bees prefer one region of the farm and visit other areas less often,” said co-author Sawyer Fuller, an assistant professor in the UW Department of Mechanical Engineering. “Alternatively, if you want to know what’s happening in a particular area, you could also program the backpack to say: ‘Hey bees, if you visit this location, take a temperature reading.'”

The data is uploaded from the backpacks into storage via backscatter when the bees return to the hive. Backscatter is a method through which devices can share information by reflecting radio waves in the environment. Right now, the team says, their packs can store about 30 kilobytes of data (which is very little), and can only upload it once they return to the hive. Going forward, the team would like to develop backpacks with live-stream cameras so farmers can monitor plant health in real time. Such a pack, however, would require instant upload capabilities (or, at least, much larger data storage).

“Having insects carry these sensor systems could be beneficial for farms because bees can sense things that electronic objects, like drones, cannot,” Gollakota said. “With a drone, you’re just flying around randomly, while a bee is going to be drawn to specific things, like the plants it prefers to pollinate. And on top of learning about the environment, you can also learn a lot about how the bees behave.”

The team will present its findings online at the ACM MobiCom 2019 conference.


Insecticides and low floral diversity are driving bumblebees into the ground

Bumblebee queens are finding it harder and harder to cope — and, as they go, so do their colonies.


Image credits Tim Hill.

It’s not easy being royalty, at least not if you’re a bumblebee. Every year after emerging from hibernation, bumblebee queens must prepare the nest, lay eggs, and rear larvae — all on their own. Needless to say, it’s a highly demanding job. And, if they fail to live up to it, there won’t be any colony. New research worryingly shows that we might be putting more on the plate of these single moms than they can shoulder.

Queen of an empty castle

The research team at the University of California Riverside reports that exposure to widely-used insecticide substances, along with poorer diets caused by reduced availability of flowers, are taking a toll on the queens. Since each must get the colony up and running by herself, the team is worried this effect will have drastic consequences on the bumblebees — a critical pollinator that’s already wavering.

Bumblebees play a key role in both natural and agricultural settings. They’re fuzzy and fast, meaning they can carry quite a lot of pollen around. They’re not picky, meaning they’ll pollinate virtually every flower they can get to. A lot of our crops today — from tomatoes to blueberries — heavily depend on bumblebees as the main pollinator species. However, unlike honey bees, bumblebee colonies need to be reset each year, starting from a single queen — making the species incredibly vulnerable during this phase.

“Queens are probably already a bottleneck for bumblebee population dynamics,” said Hollis Woodard, an assistant professor of entomology at the University of California Riverside and paper first author.

“If a queen dies because of exposure to humanmade stressors, then a nest full of hundreds of important pollinators simply won’t exist.”

Previous research has linked insecticide use — including neonicotinoids, one of the most widely-used of such compounds — with a decline in pollinator numbers. Neonicotinoids are usually applied to seeds, the team writes, but they can seep into the soil. And that’s where bumblebee queens hibernate. The compounds can also accumulate in the mature plant’s tissues, including its pollen and nectar.

Another factor that’s impacting bumblebees is declining floral diversity. This is mostly due to the use of land for agriculture and broader global changes that affect ecosystem integrity, such as climate change. According to the team, bumblebees “collect pollen from a wide variety of plant species,” and there is evidence that they need a mixed diet. Dining on pollen from a single species just doesn’t cut it for the fuzzy insects.

The team tested the effects of temporary and sustained exposure to imidacloprid — a neonicotinoid — on a queen’s mortality, activity, and ability to set-up a healthy nest. They also ran the test to see what effect a single source of pollen would have on those factors.

Their results showed that queens were significantly less active and six times more likely to die after sustained exposure to the pesticide (37 days). A shorter exposure (17 days) somewhat reduced these effects. More worryingly, even if the queens survived, they produced only a third of the eggs and a quarter of the larvae of untreated queens.

Monofloral pollen didn’t have such drastic effects, but it still noticeably influenced a queen’s activity levels and the size of its brood.

“Ours is the first study to explore the impact of multiple stressors on bumblebee queens during an understudied but important phase of their lives. It joins a small but growing body of research suggesting there are unique effects on queens that can have dramatic consequences for future generations,” Woodard said.

Woodard believes the findings are grounds for U.S. policymakers to reconsider the use of neonicotinoids. The EU has already set a ban on the use of these substances, to come into effect by the end of 2018.

Since bumblebees and pollinators on a whole are so immensely valuable to humanity, I hope Woodard’s warning is heeded.

The paper “Effects of neonicotinoid insecticide exposure and monofloral diet on nest-founding bumblebee queens” has been published in the journal Proceedings of the Royal Society B: Biological Sciences.

Popular pesticides are killing of bumblebees by preventing them from laying eggs

More and more studies add evidence to a bleak theory: our pesticides are killing off the bees.

bee bumblebee pesticide

The Buff-tailed bumblebee (Bombus terrestris). Image credits: Alvesgaspar.

Pesticides vs bees

Bumblebees don’t get nearly as much love as honey bees, but maybe they should. Sure they’re wild and they don’t produce as much honey as their “domestic” counterparts, but they help pollinate numerous fruits, vegetables, and wildflowers. Bumblebee species are declining in Europe, North America, and Asia due to a number of factors — including habitat degradation, pathogens, and pesticide use. Now, a new study analyzed the latter factor, focusing on popular pesticides called neonicotinoids, and what they found isn’t pretty, as NPR puts it. The pesticides apparently deter bumblebee queens from laying eggs.

Neonicotinoids are a relatively new class of insecticides that emerged in the 1990s. Compared to some of their predecessors, they cause less toxicity in birds and mammals. However, in recent years, they’ve come under increasing scrutiny due to their environmental impact, especially on bees and other benign insects. Neonics (as they’re also called) are systemic and move throughout growing plants. This means that traces of the pesticide reach the pollen, which the bees consume. Quite often, neonics have been found in areas that haven’t been treated, such as meadows or wildflower patches.

Because they spread so much, the impact they have on bees is far reaching and hard to thoroughly assess — yet a growing number of studies associated these pesticides with honeybee colony collapse disorder (CCD) and loss of birds due to a reduction in insect populations. While these findings remain controversial, in 2013, the European Union (and some other non-EU countries) banned the use of such pesticides, and positive results were visible fast. The ban is only temporary for now, but the EU is considering making it permanent despite complaints from pesticide companies and some farmers which claim yields have gone down.

For most of the world, neonics are still going strong, and both bees and bumblebees are paying a huge price.

Bumbling around

For the study, researchers from the Royal Holloway University of London set up an experiment involving bumblebee queens. They fed the queens a syrup which contained traces of a neonicotinoid called thiamethoxam, similarly to what a queen would be exposed to in real life.

bee bumblebee pesticides

Honeybees and bumblebees are threatened by neonicotinoids alike. Image credits: Jon Sullivan.

These queens were 26% less likely to lay eggs when they were exposed to thiamethoxam. This isn’t saying that the population would only decline by 26% — but when they modeled the impact of this 26% decrease, they found a significantly increased likelihood of population extinction.

“Without the queen laying eggs, there is no colony,” says Nigel Raine, one of the scientists who conducted the experiment. Raine helped start the experiment, but has since moved to the University of Guelph in Canada.

The problem is that the pesticide exposure is impacting bumblebee populations in conjunction with other factors, such as inadequate resources or pathogens. It’s difficult to say just how much of an effect all these stresses working together will have, but so far, it seems to be devastating.

Bumblebees are in danger in many developed countries and it’s becoming clearer and clearer that pesticides are at least partly to blame.

“Bees play a vital role as pollinators in both agricultural and natural systems. However, there is increasing concern about the state of wild bee populations. Nearly 10% of European bee species are currently considered threatened and bumblebees are declining on a global scale. The cause of these declines is thought to be a combination of factors, particularly habitat loss, parasites and diseases, invasive species, and climate change,” researchers conclude.

Journal Reference: Gemma L. Baron, Vincent A. A. Jansen, Mark J. F. Brown & Nigel E. Raine — Pesticide reduces bumblebee colony initiation and increases probability of population extinction. doi:10.1038/s41559-017-0260-1

Football-playing bees exhibit complex learning

Researchers have trained bumblebees to score goals using a mini-ball. This highlights an unexpected and unprecedented ability of the insects to learn new, complex tasks.

Footballing bees are much smarter than you think. Credit: Copyright Iida LoukolaClose

Professor Lars Chittka from Queen Mary University of London (QMUL) works at the intersection between sensory physiology, learning psychology, and evolutionary ecology. He previously showed something very interesting about bees — that they too get false memories. Honeybees and bumblebees rely on scent, taste, and color to find food (nectar), so they map this sensory information for later use, but they don’t always get it right. Just like us, sometimes they make mistakes and sometimes they get lost. Now, Chittka and his colleagues wanted to see how bees can react to a completely new situation and how they learn to adapt to it. Again, they found similarities to us.

“We wanted to explore the cognitive limits of bumblebees by testing whether they could use a non-natural object in a task likely never encountered before by any individual in the evolutionary history of bees,” said Dr Clint Perry, joint lead author and also from QMUL’s School of Biological and Chemical Sciences.

They trained bees to play football to get some delicious food. The first stage of the training was to show the bees how to identify and find the ball. After that, they had to move the ball to another location. The bees were split into three groups. Some of them watched a previously trained bee accomplish the task, the second group watched a “phantom demonstration” (a magnet moving the ball around), while the third group received no information at all. They simply had to figure it out — which they did, even though the first two groups had an easier time learning the task. But the most impressive feat was that they kicked the ball in a different way than they were taught, indicating that they had an understanding of what they were doing and not merely copying what they had seen. Joint lead author Dr Olli J. Loukola, said:

“The bees solved the task in a different way than what was demonstrated, suggesting that observer bees did not simply copy what they saw, but improved on it. This shows an impressive amount of cognitive flexibility, especially for an insect.”

During the initial demonstrations, researchers used a single ball, but after a while, they used three balls, sometimes of varying colors. The bees always chose the ball that was closest to the center (where they had to bring it), showing that they were actively trying to ease their tasks. Even when this involved walking backward (when the demonstrator bee had walked forward), they still preferred the closest ball. Scientists weren’t really expecting them to learn so quickly and effectively but this may be due to the fact that we haven’t really seen bees under mental pressure. Dr Loukola added:

“It may be that bumblebees, along with many other animals, have the cognitive capabilities to solve such complex tasks, but will only do so if environmental pressures are applied to necessitate such behaviours.”

Another interesting takeaway from this study is that you don’t really need a big brain to be smart. Tool usage (especially unnatural tool usage) is a hallmark of cognitive complexity abilities. At one point in the past, tool use was ascribed to humans alone, then was extended to primates, next to marine animals, and later to birds. It seems pretty clear that we have to extend this to insects as well. Lars Chittka concludes:

“Our study puts the final nail in the coffin of the idea that small brains constrain insects to have limited behavioural flexibility and only simple learning abilities.”

Journal Reference: Olli J. Loukola, Clint J. Perry, Louie Coscos, Lars Chittka — Bumblebees show cognitive flexibility by improving on an observed complex behavior. Science, 2017 DOI: 10.1126/science.aag2360

Bumblebee becomes the first endangered bee in continental US

For the first time in history, a bee in continental US has been listed as endangered: the rusty patched bumblebee.

Image credits: Steve Evans from Citizen of the World.

Bees all around the world are going through a dramatic decline, largely due to the effect of pesticides causing a condition called Colony Collapse Disorder (CCD). Two decades ago, the rusty patched bumblebee would have been a common sight in the US but now, it’s endangered with numbers declining in 87% of its historical habitat range.

The proposal was first made in September 2016 and was just now implemented by the U.S. Fish and Wildlife Service under the Endangered Species Act. Discussing this decision, Service Midwest Regional Director Tom Melius said,

“Our top priority is to act quickly to prevent extinction of the rusty patched bumble bee. Listing the bee as endangered will help us mobilize partners and focus resources on finding ways right now to stop the decline.”

It’s truly heartbreaking to see such a staple species nearing extinction – and the bumblebee isn’t the only one. Several other bees and pollinators are facing similar issues, although they haven’t yet been listed as endangered. These pollinating species play a key role in their ecosystem, and their demise brings with it incalculable costs. For economically important crops such as tomatoes, cranberries, and peppers alone, it’s estimated that pollinators provide environmental services of $3 billion in the US alone. Bumblebees are especially good pollinators and even plants that self-pollinate produce more and bigger fruit when pollinated by bumble bees.

“The rusty patched bumble bee is among a group of pollinators – including the monarch butterfly – experiencing serious declines across the country,” Melius said. “Why is this important? Pollinators are small but mighty parts of the natural mechanism that sustains us and our world. Without them, our forests, parks, meadows and shrublands, and the abundant, vibrant life they support, cannot survive, and our crops require laborious, costly pollination by hand.”

The reasons for the decline of the bumblebee are already classic:

  • loss of habitat;
  • disease and parasites;
  • use of pesticides that directly or indirectly kill the bees;
  • climate change, which can affect the availability of the flowers they depend on.

Aside from what officials do, the general public can also take measures to help pollinators. Planting local, native flowers, even in small urban areas can do wonders for the tiny pollinators. The use of pesticides should also be avoided, if possible (or at least limited). Foster natural landscapes and leave grass and garden plants uncut after summer to provide habitat for overwintering bees. The U.S. Fish and Wildlife Service advises:

“Grow flowers, including flowering trees and shrubs. Have a mix with something in bloom from early spring through fall. Include native milkweeds for monarch butterflies.

Bumble bees and many other pollinators (bees, moths and butterflies) need a safe place to build their nests and overwinter. Leave some areas of your yard unmowed in summer and unraked in fall, in your garden and flower beds leave some standing plant stems in winter.

Provide a pesticide free environment.”

Closeup of a bee flying by a green plant. Credit: Jon Sullivan, Public Domain licence

Bumblebees detect flowers’ electric field with their tiny hairs

Research showed flowers, and plants in general, generate an electric field. This field attracts pollinators like bees, in addition to other “advertising” methods employed by plants, like fragrances and ultraviolet emissions. Now, researchers have found out how bees are able to tune in to these fields and recognize the flowers. Apparently, their tiny hairs bend in the presence of the field, and this feeling is used to distinguish between individual flowers.

Closeup of a bee flying by a green plant. Credit: Jon Sullivan, Public Domain licence

Closeup of a bee flying by a green plant. Credit: Jon Sullivan, Public Domain licence

Scientists used to believe that animals could sense natural electric fields only in the water. Examples include sharks, eels. A few years ago, Gregory Sutton and colleagues at the University of Bristol, UK, showed that this isn’t necessarily the case.

His team devised an experiment in which some artificial flowers were connected to an electric potential of 30 Volts and sprinkled with sugar water. Another group of artificial flowers were sprinkled with a bitter liquid, but had no voltage supplied. Attracted by the sugary treat, the bees learned to visit the charged flowers. When the voltage was canceled, the bees foraged randomly as they could not differentiate between the flowers anymore.

Most recently, Sutton and colleagues revisited this problem to try to understand how the bumblebees could sense the field. Using very sensitive lasers that could measure even the slightest movements of the insects’ antennae, the researchers repeated the experiment.

Bumblebee hairs. Credit: University of Bristol

Bumblebee hairs. Credit: University of Bristol

The results suggest that when bumblebees are up to 55 centimeters away, the tiny hairs covering their bodies start to move. This motion is extremely subtle, but it can be sensed by the bees, the team reported in Proceedings of the National Academy of Sciences.

“We were excited to discover that bees’ tiny hairs dance in response to electric fields, like when humans hold a balloon to their hair. A lot of insects have similar body hairs, which leads to the possibility that many members the insect world may be equally sensitive to small electric fields,” Sutton said in a statement.

The researchers aren’t sure yet if bees really use this “in the field”, considering colour and smell are very powerful pollinating signals already. This means that the bees, and other insects most likely, could use electric fields for other purposes like navigation or communication.