Bees use shark ‘supersense’ to help find food

This article is taken from European research magazine Horizon as part of our partnership to share natural environment science stories with readers of More than a Dodo.

Armed with sensitive antennae and wide-angled compound eyes, bees have a sophisticated set of senses to help them search out pollen and nectar as they buzz from flower to flower.

But new research is revealing that bumblebees may employ another hidden sense that lets them detect when a flower was last visited by another insect.

Professor Daniel Robert, an expert in animal behaviour and senses at the University of Bristol, UK, has discovered that bumblebees have the ability to sense weak electrostatic fields that form as they fly close to a flower.

‘A bee has a capacity, even without landing, to know whether a flower has been visited in the past minutes or seconds, by measuring the electric field surrounding the flower,’ Prof. Robert explained.

The discovery is one of the first examples of electroreception in air. This sense has long been known in fish such as sharks and rays, which can detect the weak electrical fields produced by other fish in the water. Water-dwelling mammals such as platypus and dolphins have also been found to use electric fields to help them hunt for prey.

But rather than hunting for fish, bees appear to use their ability to sense electrical fields to help them find flowers that are likely to be rich in pollen and nectar.

Bees develop an electrostatic charge because as they fly they lose electrons due to the air rubbing against their bodies, leading to a small positive electric charge. The effect is a bit like rubbing a party balloon against your hair or jumper, except the charge the bees accumulate is around 10,000 times weaker.

Flowers, by comparison, are connected to the ground, a rich source of electrons, and they tend to be negatively charged.

These electrostatic charges are thought to help bees collect pollen more easily. Negatively charged pollen sticks to the positively charged bee because opposite charges attract. Once the pollen sticks to the bee, it too becomes more positively charged during flight, making it more likely to stick to the negatively charged female part of a flower, known as a stigma.

Bees develop a positive electric charge as they fly, which helps them to collect pollen from negatively charged flowers. Image credit –

But Prof. Robert and his colleagues wondered whether there could be more to this interaction. When they put an electrode in a flower, they detected a current flowing through the plant whenever a bumblebee approached in the air. Their study revealed that the oppositely charged flower and bee generate an electrostatic field between them that exerts a tiny attractive force. 

To study whether the bees are aware of this electrostatic field, they then offered bumblebees discs with or without sugar rewards. Those with sugar also had 30 volts of electricity flowing through them to create an electrical field. They showed that the bees could sense electrical field and learn that it was associated with a reward. Without the charge, bees were no longer able to correctly identify the sugary disc.

Research by another group published shortly after Prof. Robert’s own work also showed that honey bees are also able to detect an electrical field. But exactly how the insects were able to do this remained a mystery, leading Prof. Robert to set up the ElectroBee project.

Very few animals have the capacity to read the stars and use it to find, north, south, east or west.
Professor Eric Warrant, Lund University, Sweden

He has discovered that fine hairs on the bees’ bodies move in the presence of weak electrical fields. Each of these hairs has nerves at its base that are so sensitive they can detect tiny movements – as little as seven nanometres – caused by the electrical field.

Prof. Robert believes that when a bee visits a flower, it may cancel out some of the negative charge and so reduce the electrostatic field that forms when bees approach. This change in the strength of the electrostatic field could allow other bees flying past to work out whether a flower is worth visiting before they land, helping to save time and energy.

Other signals, such as changes in the colour and smell of flowers, happen in minutes or hours, while switches in electric potential occurs within seconds.

Prof. Robert and his team are now testing their theory that the electric field helps bees know which flowers to visit by counting visits by bumblebees to flowers in a meadow this summer and measuring electric fields around the flowers.

Their findings could help scientists better understand the relationship between plants and pollinating insects, which may prove crucial for improving the production of many vital fruit crops that rely upon bees for pollination.

Prof. Robert is also investigating whether bumblebees use their electrostatic charge to communicate to their nest sisters about the best places to fly for pollen.

But while bumblebees use their extraordinary sensory power to find food just a few kilometres from their nests, another insect is using another hidden sense to make far longer journeys.

The Bogong moth can travel more than 1,000km to hibernate in caves during the Australian summer. Image credit – Lucinda Gibson & Ken Walker, Museum Victoria/Wikimedia, licenced under CC BY-SA 3.0

In Australia, Bogong moths (Agrotis infusa) flitter steadily from various parts of the country and make their way towards the Snowy Mountains in the southeast. They fly for many days or even weeks to reach the high alpine valleys of the highest mountain range in the country, sometimes travelling over 1,000km. Once there, the insects hibernate in caves typically above 1,800m for the Australian summer, before making the return journey.

The only other insect known to migrate so far is the monarch butterfly in North America. But while the monarch butterfly relies in part on the sun’s position for navigation, the moths fly by night. Professor Eric Warrant, a zoologist at Lund University in Sweden, has been fascinated with how these insects, just a couple of centimetres in length, managed such a feat ever since he was a student in Canberra, Australia.

Moth mystery
He suspected that the moths might use the Earth’s magnetic field to find their way, so his team tethered moths to a stalk that allowed them to fly and turn in any direction before surrounding them with magnetic coils to manipulate Earth’s magnetic field.

For two years, experiments failed. While the moths did appear to be influenced by the magnetic field, they were using something else to navigate too – their vision.

‘It is a little like how we would go hiking,’ said Prof. Warrant, who is trying to unravel how the moths sense the Earth’s magnetic fields in his project MagneticMoth. ‘We’d take a reading from a compass, then look for something to walk towards in that direction, a tree or mountain peak.’

His research has already shown that the moths check their internal compass every two or three minutes and continue to make for a visual cue ahead. But what are the insects able to see at night?

Further research revealed something remarkable. When Prof. Warrant downloaded an open source planetarium programme called Stellarium and projected the Australian night sky above the moths, he discovered they were using the stars.

‘Very few animals have the capacity to read the stars and use it to find, north, south, east or west,’ said Prof. Warrant. ‘We (humans) learnt how to do it. Some birds do it.’

But insect eyes of bogongs mean they don’t simply follow one guiding star. Rather they are sensitive to panoramic scenes.

‘In the southern hemisphere, the Milky Way is much more distinct than it is here in the northern hemisphere,’ said Prof. Warrant. ‘It really is a stripe of pale light in which there are interspersed very bright stars.’ He believes that the moths are at least in part guided to their cool alpine caves by the light of the Milky Way.

Prof. Warrant believes that Bogong moths naviagte in part by using the Milky Way as a guide. Image credit – Dave Young/Flickr, licenced under CC BY 2.0

The discovery could also lead to the development of new types of navigation for our own species too. GPS, for example, relies upon a constellation of satellites that are vulnerable to disruption. Prof. Warrant believes studying an insect capable of flying 1,000km to a cave using a brain the size of a rice grain, could help us find alternatives too.

‘Animals seem to solve complex problems with little material and low amounts of energy,’ Prof Warrant said.

The research in this article was funded by the EU. If you liked this article, please consider sharing it on social media.

This post Bees use shark ‘supersense’ to help find food was originally published on Horizon: the EU Research & Innovation magazine | European Commission.

Top image: Fine hairs on bees’ bodies can sense tiny changes in electrostatic fields, enabling them to sense whether another bee has visited a flower before them. Image credit – Unsplash/George Hiles, licenced under Unsplash licence

Understanding beeswax

By Tuuli Kasso, PhD in Science Fellow at the Natural History Museum of Denmark, University of Copenhagen. Tuuli is a visiting researcher, who has used the Museum’s collection to help her understanding of beeswax. 

When working on the dissertation for my MSc in Archaeological Science last year, I explored the medieval craftsmanship of sealing wax. I was interested in the way the medieval wax seals had flaked, as the beeswax dried out. Drawing on my previous education in conservation techniques, I began a close investigation of the prestigious material, beeswax.

Medieval craftsmen used a range of dangerous materials to make sealing wax. The red pigment cinnabar, a mercury (II) sulphide, and red lead, are now known to be extremely poisonous.

Although some of the ingredients of sealing wax are very hazardous, there is nothing dangerous in beeswax… except the bees! Produced by honey bees, Apis mellifera, honey and beeswax were important commodities in the Middle Ages. Beekeeping was a skilful profession, housing colonies in woven hives, known as skeps. Colonies were carefully selected to overwinter for the next season.

Manuscript illuminations provide detailed information on the types and construction of beehives in the Middle Ages.England, 13th century. British Library Royal 12 C XIX f. 45.

Beeswax was also important in the Middle Ages for lighting, and beeswax candles were preferred for their pleasant smell. After the Protestant Reformation in the 16th and 17th centuries, the religious use of candles decreased, so demand for beeswax declined.

Even today, the Catholic and Orthodox Churches still require the candles they use to contain a proportion of beeswax.

On my quest to understand the degradation of beeswax in sealing wax and write my disseration, I was very lucky to use some samples from the entomological collections from the Oxford University Museum of Natural History. After some early mornings spent amongst the Westwood collection, I found the perfect specimens of natural honeycombs, from the 19th century. The old hand-written labels were also a lovely encounter when exploring the historical collections.

I compared the samples to modern beeswax and medieval seal samples, and learned that the degradation of beeswax is caused by multiple factors, triggered also by storage conditions. The composition of beeswax is very complex, and there are differences caused by the age of the bee in addition to geographical provenance.

A selection of bee specimens from the Museum’s collection.

The recent catastrophic decline of bee populations has drawn focus to save the bees, and in my PhD research (University of Copenhagen and University of Cambridge) I will explore the recovery of ancient DNA and proteins of bees from beeswax, to cast light on the health of bee populations over time.

Image credit - Gilles San Martin, licensed under CC BY-SA 2.0

Decoding the honeybee dance

Image credit - Gilles San Martin, licensed under CC BY-SA 2.0

This article is taken from European research magazine Horizon as part of our partnership to share natural environment science stories with readers of More than a Dodo.

Unravelling one of the most elaborate forms of non-human communication – the honeybee’s waggle dance – could help researchers better understand insect brains and make farming more environmentally friendly.

It’s part of a field of work looking at insect neurology which is helping to unravel the complexity of their brains.

Bees have evolved a unique, and ingenious, way to communicate with each other – the waggle dance. By shaking their abdomens in a particular way, a bee can tell others in its hive the specific direction and distance of a food source or a new site for a nest.

‘If nectar or pollen is in the direction of the sun, a bee will run a figure of eight that is orientated towards the top of the hive. If pollen is found 90 degrees from the sun they will point that way instead,’ explained Dr Elli Leadbeater, a bee expert from the School of Biological Sciences at the University of London, in the UK.

The longer the bees spend dancing corresponds to the better quality of a food source, while the more time spent on each figure eight represents the distance from the pollen or nectar.

Researchers now believe that decoding this information-packed dance further could reveal a link between bees’ brains and how the surrounding environment affects them. In a project called BeeDanceGap, Dr Leadbeater is working to identify the exact genes in the bee brain that play a role in helping the insects understand this waggle dance.

To do this, researchers must first identify the best dancing bees in a test hive and watch them as they reveal a food source to other worker bees. The newly educated bees are then captured as they leave the hive so their brain tissue can be genetically analysed to determine which genes associated with learning and memory were activated from following the waggle dance.

Only a few individuals are used in this way and the genetic data provides a deep insight into the neurology of a bee’s brain – at a time crucial to their future.

The observation bee hive at the Oxford University Museum of Natural History gives visitors a glimpse into hive life.


Beekeepers around the world have reported that many of their bees leave and never come back, causing hives to suddenly collapse. Experts believe there are several factors contributing to this widespread loss of bee colonies, including climate change, parasites and habitat loss. Agrichemicals like pesticides and neonicotinoids, which are used to kill unwanted insects on farms, have also been strongly linked to the problem.

‘The rate pesticides or neonicotinoids are applied to crops don’t necessarily kill bees but they make them worse at foraging,’ said Dr Leadbeater.

If you do damage to just one part of the brain of a lot of individual bees, it can have huge consequences for the whole colony.
Dr Elli Leadbeater, University of London, UK

Neonicotinoid pesticides have been found to bind to parts in the insect brain, disrupting neural transmission. This leads to some brain cells either failing to develop or not functioning properly.

The EU recently banned neonicotinoids, which Dr Leadbeater believes is a huge step forward in protecting bees, but she said governments still need more rigorous ‘long-term environmental safety monitoring’. Without this, there is a risk that other agricultural products used in place of neonicotinoids could impact honeybees in a similar way.

But when the first results of BeeDanceGap are published later this year, they could contribute to building better criteria for testing future agriculture practices or products. Dr Leadbeater believes it will provide a new understanding of a bee’s brain, and so help identify problems sooner.

The impacts of quickly identifying problems go far further than just supporting beekeepers and their insect charges. Protecting honeybees, along with bumblebees and wild bees, is also essential to maintain a healthy and productive environment. These insects pollinate over 80% of crops and wild plants in Europe. According to Professor Martin Giurfa, from the Research Center on Animal Cognition at CNRS in France, ‘preserving little brains is about preserving biodiversity’.

Honey bees working inside a hive

More than machines

Honeybees have a higher social complexity than many other species. Alongside the waggle dance communication, each hive has a division of labour where different workers have responsibility for a variety of tasks – such as foraging for pollen, nursing the young, building hives and even removing the dead.

Prof. Giurfa is co-leading the BrainiAnt project, which looks at how this type of complex social behaviour evolved and how it affected the structure of insect brains. He said that when ‘you understand how bees perceive the world, it is easier to find ways to protect them’.

Through the work of researcher Dr Sara Arganda, the project is investigating a part of the insect brain called the mushroom body, where learning occurs and long-term memories are stored. Researchers analysed bee behaviour and gave them memory tests, such as navigating paths using colour cues, in order to learn more about the structure of insect brains.

The project strengthened the argument that bee brains are more complex than previously thought. ‘Most findings are saying that insects are more than simple machines, which comes from studies in the honeybee,’ said Prof. Giurfa. ‘(But) the entrance region of the mushroom body shows a level of complexity and the studies show that this complexity is not rigid, it is plastic.’

This means its structure is changing all the time, which mirrors how human brains work. ‘(Bee) brains are capable of sophisticated performances such as learning concepts and rules; they are incredible organs and they need to be defended,’ said Prof. Giurfa

To further advance understanding of the mushroom bodies and how they function in different species, the project is being co-led by Professor James Traniello at Boston University in the US, an expert in ant evolutionary neurobiology.

Ants, which are related to honeybees, have brains that may be 100 times smaller, and due to their minute size, provide insights into how insect brains are structured.

‘What happens to neural tissue at an extremely small size?’ asked Prof. Traniello. ‘Are you losing neurons, are neurons becoming more efficient in their actions, how many neurons do you have to string together to form a circuit that enables behaviours as complex as what you would see in ants? How does the collective intelligence of an ant colony impact the structure of the brain?’

If BrainiAnt can answer these questions, it would provide a clearer picture of the evolution and function of ant brains.

‘The next step is trying to understand the genes that are involved in regulating brain size, compartment variability, metabolism and other functions,’ said Prof. Traniello.

He added that a better understanding of neural tissue could also help to guide attempts to genetically engineer bees so their brains are resistant to environmental threats like neonicotinoids. Although far off, it could mean that bees, and the benefits they bring to the environment, will have a more secure future.

The research in this article was funded by the EU.


The issue

One in ten pollinating insects is on the verge of extinction, and a third of bee and butterfly species are in decline.

On 1 June, the European Commission launched a proposal to tackle this problem at an EU level. It includes a new monitoring process to collect quality data and identify trends, action plans to protect insect habitats and incentives for businesses such as those in the agrifood sector, to contribute to conservation.

The proposal, known as the EU Pollinators Initiative, has a number of short-term actions to be taken before 2020, at which point the progress will be reviewed.

This post Decoding the honeybee dance could lead to healthier hives was originally published on Horizon: the EU Research & Innovation magazine | European Commission.

The bully bee


Young volunteers Genevieve Kiero Watson and Poppy Stanton tell the tale of the Museum’s resident Wool Carder Bee and their investigative bee work in our Life Collections…

A small guardian patrols its territory among the luscious bed of Lamb’s-ears that grow at the front of the Museum. This feisty critter, the Wool Carder Bee (Anthidium manicatum), is just one of the roughly 270 bee species that buzz around Britain. Having spotted this unusual hovering bee we seized the opportunity to identify, photograph and explore the species a little further.

The male of this solitary bee species is fiercely territorial, fighting off other males as well as any other insects it considers to be intruders. Techniques used in combat vary from skilful aerial hovering to ferocious wrestling. But perhaps its greatest weapon is a series of stout spines found at the tip of the abdomen. These are used to bully an intruder into submission, or even to kill it. In so doing, the male protects the precious supply of pollen for the smaller females which in turn collect it on stiff bristles on the undersides of their abdomens.

Females, being slightly less aggressive, are in charge of constructing the nests, which are built in existing cavities such as beetle holes. Hairs shaved off plants, such as the favoured Lamb’s-ear, are used to create the brood cells for the next generation.

Male Wool Carder Bee on Lamb's ear in the Museum's front garden
Male Wool Carder Bee on Lamb’s ear in the Museum’s front garden

The Museum houses many specimens of the Wool Carder Bee and our job was to pull out the data from each one to help with an ongoing online survey about this species. Although making friends with hundred-year-old bees was enjoyable, trying to comprehend the miniscule handwritten labels accompanying them was altogether more trying.

Every label explains where and when the bee was captured, who collected and identified it, and gives the reference for its current collection. All this on a slip of paper no bigger than half a stamp.

One of the Musuem's Wool Carder Bee specimens, circled, featured in a display of all 270 species of British bee in the Bees (and the odd wasp) in my Bonnet exhibition by artist Kurt Jackson
One of the Museum’s Wool Carder Bee specimens, circled, featured in a display of all 270 species of British bee in the Bees (and the odd wasp) in my Bonnet exhibition by artist Kurt Jackson

After recording data from 120 labels we began to find the grid reference of the location each was originally collected. This too was challenging as many place names have changed in the last hundred years. Ultimately, the information will be used by the Bees, Wasps & Ants Recording Society (BWARS) to improve the distribution map for the Wool Carder Bee.

Why not see if you can spot the Wool Carder Bee in your garden? Characteristics to look out for include small spines on the tip of the abdomen and lateral lines of yellow spots on either side of the abdomen. The bees themselves are about 11-13mm long for females, and 14-17mm for males. Good luck!