The sentience of bees: Investigations at Lars Chittka’s bee lab
Professor Lars Chittka’s book The Mind of a Bee is making an impact far beyond the world of entomology. And so it should. Lars and his researchers in the Queen Mary University of London bee lab have been trying to understand just how a brain the size of a sesame seed produces such sophisticated behaviours. As interest in the sentience of animals rises up the political agenda, this work takes on added significance.
Professor Lars Chittka’s book The Mind of a Bee is making an impact far beyond the world of entomology. And so it should. Lars and his researchers in the Queen Mary University of London bee lab have been trying to understand just how a brain the size of a sesame seed produces such sophisticated behaviours. As interest in the sentience of animals rises up the political agenda, this work takes on added significance.
Images of bees playing with balls provide cute pictures for the media, but they also lead to profound questions. With human diets inevitably about to change, probably to include eating insects, work on insect sentience has far-reaching implications. For beekeepers, that bees might be sentient has either been a shock or confirmation of years of beekeeping experience. There is a lot going on in those bee brains that our big brains are only beginning to get our heads around.
So, it was with excitement and curiosity that fellow co-editor Richard Rickitt and I travelled to the Queen Mary bee lab to speak to Lars Chittka and his team of researchers about their work. Lars had allowed us to speak, with no limitations, to any researchers who happened to be in the unit that day.
It would not be too much of a flight of fancy to say that a buzz greets visitors as they enter the lab, which comprises two linked large rooms with Lars’s office off to one side and daylight coming through the large window overlooking a balcony roof at one end. When we arrived, several researchers were busy studying bumblebees in cages with all manner of Heath-Robinson style home-made appliances straight out of a Blue Peter studio – for such cutting-edge research, there is little ready-made kit.
Although Lars arrived in the lab in 2002, the unit has a much longer history of bee research. In the 1970s, Lesley Goodman (acclaimed for her beautiful book Form and Function in the Honey Bee) sat in the very same office that Lars occupies today. Until a few days ago there had even been a long-established apiary on the balcony visible from the lab. With regret, Lars had just given up the bureaucratic struggle with university health and safety personnel who couldn’t quite come to terms with a few tens of thousands of stinging insects sitting high up above students milling below.
The unit hasn’t abandoned the study of honey bees, but bumblebees are more practical research subjects for indoor behavioural experiments, and are just as ‘intelligent’ (except, of course, they lack the famous dance language of honey bees).
The bee lab researchers and subjects
Today in the bee laboratory, about ten different MSc, PhD and postdoc projects are underway, each junior researcher having their own project which they direct, rather than being part of a larger multi-researcher project. However, their overall focus is on the psychology and learning behaviour of bees and that is unique in the UK, says Lars. A dominant theme that has emerged from the team’s work is that of the sentience and consciousness of bees – do they have the capacity to enjoy activities and do they suffer pain? That ethical concern extends to the sensitive and careful treatment of bees in the lab.
The laboratory subjects are bumblebees supplied by commercial pollination operators. They are kept in a range of fairly large Perspex-topped containers for observation, with their covered nests in corners of the observation boxes. The walls of many of the boxes are decorated with wallpaper patterns so as to help the bees orientate. They survive and breed during all seasons in these conditions. Now that the honey bees have left the building, any work on Apis mellifera is done by individual researchers in their home apiaries.
With that thought, we were introduced to each of the students and their projects. They were at various stages of their PhD research, so their findings had to be couched carefully and, of course, we could only scratch the surface and hear about certain aspects of their years of research.
Are bees sentient?
Having overseen these experiments and very many more, what is Lars Chittka’s assessment of the sentience of bees? Can we be sure they are sentient?
“Unfortunately, at present this question cannot be answered with a formal scientific proof for any non-human species – or indeed for an AI (artificial intelligent) system. We can only use common sense and probabilities. We can observe the apparent capacity of bees to feel pain, to behave as if anxious after predator attacks, to go out of their way to ‘play’ with objects, and to have dopamine-dependent positive emotion-like states. They also appear capable of solving certain problems by thinking rather than trial and error. They know their own body dimensions and appear to ’know what they know’. Taking all of this together, I am now about 80% certain that they are conscious, sentient beings.”
Lars Chittka
Born near Frankfurt in 1963, just 20 months after the construction of the Berlin Wall, and growing up mostly in northern Germany (then West Germany), Lars Chittka had an early interest in psychology but went to the nearby university in Göttingen to study biology before taking the bold step of transferring to the Free University of Berlin. That’s career suicide, said his professor, it’s terrible; they just plot revolutions there. Getting over the shock, the professor did admit that there was one good lab there – the one studying honey bees. One good lab is good enough for me, thought Lars.
As a teenager Lars would enjoy reading Psychology Today and since then his work in biology has been influenced by psychology themes. In the mid-2000s, in the biology department at Queen Mary, he responded to a call for new undergraduate degree suggestions with a successful proposal for a psychology programme. Alongside academics with expertise in cognition in animals, he learned a lot in what is now called the Department of Biological and Experimental Psychology, the department of which the current bee lab is a part.
Samadi Galpayage
Do bees play and do they benefit from it?
Originally considering a medical degree, Samadi Galpayage became more interested in ecology and evolutionary biology and changed tack. Having obtained a biology degree at the University of Bristol and a Masters at Queen Mary, she is now working towards a PhD. Watching animal behaviour fascinates her, and that is fortunate because her work involves patiently watching, videoing and recording bumblebees moving balls.
We interrupted Samadi during one of her tests to see if the bumblebees living in her laboratory box could be developing their motor and or cognitive skills by rolling wooden balls around as a form of play. After one group of bees, marked with a numbered disc on the thorax for identification, had had ten days of playtime, they were given snapdragon flowers laced with unscented sugar syrup to see if they could get to the nectar in this flower, a notoriously difficult one for bees to manipulate. Doors to the relatively large play area enabled different groups of bees from the same colony to be given the opportunity to play in different chambers, one containing mobile balls and another immobile balls.
Although Samadi’s data set was relatively small when we met her, she had already noticed that there might be some difference (not yet statistically significant) that bees which had practised at ball rolling tended to enter the flowers more quickly. She has also noticed what she interprets as different bee personalities – some were bold, some hesitant. She has also spotted a difference in activity levels related to age (also commonly observed in mammals) – younger bees tend to move the balls around more than older ones – and also that males play for longer periods than females.
Relatively low-cost, mainstream technology – in the form of the smartphone camera – gave Samadi high-quality footage which she could analyse later.
In future, Samadi hopes to continue to work in cognition andto further explore why we think humans are so special compared to other animals. Considering the tiny size of bumblebee brains and their capabilities, Samadi says she has found her work very humbling.
Samadi was helped in her work by Chisom Aniebo, a voluntary intern and soon-to-be second-year psychology student. Chisom had never expected to be working with animals, let alone insects, but has been captivated by their behaviours and astonished that they can be trained.
Vince Gallo
How do honey bees build comb?
Vince Gallo, now retired from paid work but not letting up in the slightest, has brought his engineering knowledge and prodigious software-writing skills to the world of biology.
A beekeeper for many years, Vince’s natural curiosity led him to question and test what he was reading in the bee books. He realised that there must be some mechanism to explain the sophisticated organisation within the hive – a gradation of the workforce based on the differing responsiveness of individual bees to particular stimuli. For such “an immense logic”, he wanted to write some simulation software.
From a simulation of the activities of one virtual bee, he scaled up to 10,000 bees, each with a little bit of randomness built into their behaviour. Using gaming software, he produced a visual representation of bees’ movements in three dimensions and particularly focused on comb construction and its use – where the queen lays and where the workers put nectar and pollen.
At first, he began to develop rather exotic theories about why brood should be in the centre of a comb in free-living colonies. However, he soon realised that is too easy a question and “monumentally boring”. The answer? As laying stops, the brood nest contracts and where else would you expect the brood to be – in the middle of course!
However, that led Vince to more difficult and stimulating questions. How do bees build comb and produce cells with hexagonal structures? Investigating how bees build cells with straight sides, Vince realised that’s not really how it happens. Through image analysis over time (with sophisticated video and imaging techniques which he now shares with others in the lab), he has been surprised, alarmed even, to see how sections of comb migrate by a cell width or two within the hive.
The hexagonal structure of cells, Vince explains, is even more complex than it first appears. A circular cell becomes hexagonal as soon as cells are built alongside it – the opposing cell sides are initially built to have a curved outer surface. He has shown that bees, when forced to build cells that don’t have a cell adjacent to them, build curved walls. However, as soon as there is cell alongside, the wall becomes flat. The bees working on either side have had to come to a compromise – a flat surface results. The same would happen with a cell built on the other side of the comb, but because the cell bottoms don’t align exactly, a triple-faceted cell bottom usually results.
“So, you’ve got bees assessing conditions, you’ve got decision making, and you’ve got learning or cognition. Whatever you call it – thinking – is a very contentious topic. But there is evidence that they are going through some assessment process.”
A few weeks later, Vince obtained his PhD and Dr Gallo now plans to continue funding his own work to explore aspects of the bee brain further.
Matilda Gibbons
Do bees feel pain?
To investigate if bumblebees feel pain, Matilda Gibbons was recording the temperatures bees will put up with to access solutions of differing sugar concentrations. This was one of a series of experiments about bumblebees and pain thresholds that would be documented in her PhD thesis.
In one experiment, the bees had a choice of standing on different coloured pads to access a sugar solution reward. But each colour of pad was heated to a different temperature and the sugar reward varied – a relatively high sugar solution concentration on the hottest pads, a lower concentration on the cooler pads. How hot a pad would they tolerate to obtain the greatest reward?
In another experiment, Matilda had studied the behaviour of bees in response to probes of varying temperatures. In this test, she also administered analgesics to the bees
(a novel and tricky technique in itself)
to see if that raised the pain thresholds
of the bees.
These two experiments, which focus on two of the main eight generally recognised pain criteria, had never been tried on bees before, so Matilda’s research design had to be very innovative.
And what do people think of Matilda’s work? It varies, she says: “A friend said: well of course bees don’t feel anything, they are way too small to feel pain. But my mum said the opposite: well, of course they feel something. Why would you ever doubt that? They’re animals; of course they can feel pain.” Perhaps Matilda’s work can settle that disagreement and a few others besides.
During her psychology degree at King’s College London, Matilda had been drawn to the neural rather than the social aspects of the subject. Seeing an advertisement for a PhD post in Lars’s lab, she was immediately attracted to it because it combined topics she was interested in: animal welfare, insects and science. When we spoke, in her final year as a PhD student, she was hoping to continue to work in the field, especially with mammals.
Andrew Crump
Can bees connect events?
As one of several experiments, five or six in all, Dr Andrew Crump wants to discover if bumblebees can make a connection between two events separated by a period of time, and if they realise that one event can be the precursor to the second.
Andrew is studying what is known scientifically as trace conditioning, first described by Pavlov with his salivating dogs. In human terms, an example of trace conditioning might be how we can learn to connect a succession of flashes of light followed by a puff of air to the eye by closing our eyes when a flash is detected (unless we are distracted in the meantime – an added complication).
If bumblebees can react to a similar pairs of stimuli, it would show a degree of learning capability and suggest that they can consciously realise that the first seemingly unimportant stimulus is significant.
In determining consciousness, Andrew explains that there isn’t one golden bullet, but there are indicators that can build up an overall assessment of consciousness. And, he says, it seems just as difficult to find evidence to disprove that bees have consciousness as to prove it.
After a first degree at Oxford, Andrew obtained his PhD at the Queen’s University of Belfast biology department. His work motivation comes from a disagreement with those who say that we can’t know anything about what an animal feels – he believes that these are questions at least worth asking.
Although the practical scientific part of Andrew’s work is being carried out in Lars’s bee unit, he is also in the London School of Economics philosophy department. In that context, his work has a policy development dimension. His research is part of the LSE Foundations of Animal Sentience project, where a team has already been contributed to the policy development for the UK’s 2022 Animal Sentience Act (see Chris Palgrave’s article in BeeCraft, June 2022). That act of parliament recognised crabs and lobsters as being sentient. Insect sentience hasn’t yet been addressed in legal terms, but that may change in the future.
Alice Bridges
Can bees learn from each other?
Days before her PhD viva, Alice Bridges told us about social learning in bumblebees and how a behaviour acquired by one bee spreads throughout the group and maintained like a behavioural tradition.
Alice has demonstrated this social learning by presenting a bee with a puzzle box representing a flower which the bee had to open to obtain food. Through ‘incremental training’, she started by presenting the bees with an easy task (only the last stage of getting to the reward), but then she made the task progressively more difficult as the bee had to learn the earlier stages to reach that final prize. Once the bee had been trained to complete the whole task, it was put back in its colony and all the bees were filmed to see if the trained bee’s behaviour would spread throughout the group. And that’s exactly what happened: bees learned the same method of opening the boxes as was shown to them by the demonstrator.
There were some surprises. Although every so often individual bees would solve the problem using the alternative method, they would always revert to the method that the trained bee had ‘shown’ them. Even more surprising, some bees which were given puzzle boxes without a demonstrator also worked out how to open them – although they weren’t as good as bees that had a demonstrator to copy.
Alice explains that it’s hard to say if the observer bees are watching the demonstrator bees purposefully. By a form of social learning called ‘local enhancement’, bees are drawn to each other, so they will inevitably be exposed to the behaviour of other successful bees and may be able to scrounge some of those bees’ reward leftovers. In that way, the watching bees receive the food reward – and that’s how the behaviours may spread.
Once, Alice even observed that a demonstrator bee stopped a successful behaviour apparently because the other bees were stealing part of her reward. However, when the other bees were not around, that demonstrator bee would return to her successful behaviour. Sadly, that set of observations couldn’t be explored further because the pandemic struck – with all the lockdown consequences for work in the lab.
Meanwhile, Alice even saw some observer bees, realising that the demonstrator bee could get a reward, hang around that bee until it had successfully reached the reward, then pull it back and go over the top of it to steal the reward!
The cultural aspect of the learning fascinates Alice. She told us of communities of orca whales that have developed different eating habits across the world by learning from each other within the group – some groups had become fish eaters, others seal eaters. Such cultural differences were once thought to be characteristic only of humans, but Alice thinks the phenomenon maybe much more widespread throughout the animal kingdom.
Days later, Dr Alice Bridges did indeed complete her PhD successfully despite the pandemic lab lockdowns and even having to undergo desensitisation after a severe reaction to
a bumblebee sting.
We thank Professor Lars Chittka and the Queen Mary University bee unit researchers for their openness and patience in answering our questions and wish them well in their studies. For us, it was a very special day and one that will resonate for a very long time, significantly affecting how we manage our honey bees.
Stephen Fleming, co-editor
Stephen Fleming is co-editor of BeeCraft, the international award-winning honey bee and beekeeping magazine. A beekeeper for more than 30 years, he is a researcher by training and obtained a PhD at the University of Reading. He has been interested in environmental issues since he was a child and beekeeping continues to open yet more doors that increase his understanding of the natural world.
