It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Tuesday, March 07, 2023
Bees follow linear landmarks to find their way home, just like the first pilots
Study suggests that honeybees search for linear landscape elements that match mental map of home area
Peer-Reviewed Publication
IMAGE: A HARMONIC RADAR TRANSPONDER ATTACHED TO THE THORAX OF A FORAGER HONEYBEE.view more
CREDIT: E BULLINGER, U GREGGERS, R MENZEL
In the earliest days of human flight, before the invention of the first radio beacons and ground-based electronic systems, and modern GPS, pilots commonly navigated by following roads and railways – striking linear landscape elements at ground level that guide towards a destination of interest.
Enter the honeybee. A century of research has shown that honeybees are navigators par excellence. They can navigate by their sense of smell, the sun, the sky’s pattern of polarized light, vertical landmarks that stand out from the panorama, and possibly the Earth’s magnetic field. They are also clever learners, able to recognize associations between disparate memories in order to generalize rules.
Now, scientists have shown that honeybees tend to search for their way home by orienting themselves in relation to the dominant linear landscape elements, just like the first pilots. The results are shown in Frontiers in Behavioral Neuroscience.
Dr Randolf Menzel, an emeritus professor at the Department of Neurobiology of the Free University of Berlin, and the study’s lead author, explained: “Here we show that honeybees use a ‘navigation memory’, a kind of mental map of the area that they know, to guide their search flights when they look for their hive starting in a new, unexplored area. Linear landscape elements, such as water channels, roads, and field edges, appear to be important components of this navigation memory.”
Tiny transponder
In late summer of 2010 and 2011 near the village of Klein Lüben in Brandenburg, Menzel and colleagues caught 50 experienced forager honeybees and glued a 10.5-mg transponder on their back. They then released them in a new test area, too distant to be familiar to the bees. In the the test area was a radar, which could detect the transponders at a distance of up to 900 meters. The most notable landmark in the test area was a pair of parallel irrigation channels, running southwest to northeast.
When honeybees find themselves in unfamiliar territory, they fly in exploratory loops in different directions and over different distances, centered on the release spot. With the radar, the researchers tracked the exact exploratory flight pattern of each bee for between 20 minutes and three hours. The bees flew at up to nine meters above the ground during the experiment.
The researchers had collected foragers from five hives: the home area around hives A and B resembled the test area in terms of the number, width, length, and angle of linear landscape elements, especially irrigation channels. The home range around hives D and E was highly dissimilar in this regard, while the home area around hive C was intermediate in similarity to the test area. Other landmarks by which honeybees are known to find their way, such as structured horizons or vertical elements that stand out, were absent in the test area.
Non-random search pattern
Menzel et al. first simulated two sets of random flight patterns, centered on the release spot, and generated with different algorithms. Since the observed flight patterns were highly different from these, the researchers concluded that the honeybees didn’t simply conduct random search flights.
The researchers then used advanced statistics to analyze the orientation of flights and their frequency of flying over of each 100 x 100 meter block within the test area. They showed that the honeybees spent a disproportionate amount of time flying alongside the irrigation channels. Analyses showed that these continued to guide the exploratory flights even when the bees were more than 30 meters away, the maximum distance from which honeybees are able to see such landscape elements. This implies that the bees kept them in their memory for prolonged periods.
“Our data show that similarities and differences in the layout of the linear landscape elements between their home area and the new area are used by the bees to explore where their hive might be,” said Menzel.
Navigational memory
Importantly, machine learning algorithms showed that the irrigation channels in the test area were most informative for predicting the exploratory flights of bees from hives A and B, less so for bees from hive C, and least for bees from hives D and E. This suggests that the bees retained a navigational memory of their home area, based on linear landscape elements, and tried to generalize what they saw in the test area to his memory to find their way home.
“Flying animals identify such extended ground structures in a map-like aerial view making them highly attractive as guiding structures. It is thus not surprising that both bats and birds use linear landmarks for navigation. Based on the data reported here we conclude that elongated ground structures are also salient components of the honeybees’ navigation memory,” concluded the authors.
A new study has shown that bumblebees pick up new “trends” in their behaviour by watching and learning from other bees, and that one form of a behaviour can spread rapidly through a colony even when a different version gets discovered.
The research, led by Queen Mary University of London and published in PLOS Biology, provides strong evidence that social learning drives the spread of bumblebee behaviour – in this case, precisely how they forage for food.
A variety of experiments were set up to establish this. The researchers designed a two-option puzzle box that could be opened either by pushing a red tab clockwise or a blue tab counter-clockwise to reveal a 50 per cent sucrose solution reward.
‘Demonstrator’ bees were trained to use either the red or blue tabs, with ‘observer’ bees watching. When it was the observers’ turn to tackle the puzzle, they overwhelmingly and repeatedly chose to use the same method that they had seen, even after discovering the alternative option. This preference for the taught option was maintained by whole colonies of bees, with a mean of 98.6% of box openings made using the taught method.
The importance of social learning to the acquisition of puzzle box solutions was also illustrated through the control group, which lacked a demonstrator. In this group, some bees managed to open the puzzle boxes, but did so far fewer times than those who benefitted from seeing another bee do it first. The median number of boxes opened in a day by the observer bees with a demonstrator was 28 boxes a day, whereas it was only 1 for the control colony.
In an additional experiment, the researchers put both ‘blue’ and ‘red’ demonstrators into the same populations of bees. In the first population, 97.3% of the 263 incidences of box-opening by observers by day 12 used the red method. In the second population, observers preferred the blue method over the red on all days except one. In both cases, this demonstrated how a behavioural trend might emerge in a population in the first place – for the most part, due to experienced bees retiring from foraging and new learners arising, rather than any bees changing their preferred behaviour.
Similar results from similar experiments have been used in species such as primates and birds to suggest that they, like humans, are capable of culture. If bumblebees are capable of this, too, this could potentially explain the evolutionary origin of many of the complex behaviours seen among social insects. It might be possible that what now appears instinctive could have been socially learnt, at least originally.
Dr Alice Bridges, the lead author from Queen Mary University of London, said: “Bumblebees – and, indeed, invertebrates in general - aren’t known to show culture-like phenomena in the wild. However, in our experiments, we saw the spread and maintenance of a behavioural “trend” in groups of bumblebees – similar to what has been seen in primates and birds. The behavioural repertoires of social insects like these bumblebees are some of the most intricate on the planet, yet most of this is still thought to be instinctive. Our research suggests that social learning may have had a greater influence on the evolution of this behaviour than previously imagined.”
Professor Lars Chittka, Professor of Sensory and Behavioural Ecology at Queen Mary University of London and author of the book ‘The Mind of a Bee’, said: “The fact that bees can watch and learn, and then make a habit of that behaviour, adds to the ever-growing body of evidence that they are far smarter creatures than a lot of people give them credit for.
“We tend to overlook the “alien civilisations” formed by bees, ants and wasps on our planet – because they are small-bodied and their societies and architectural constructions seem governed by instinct at first glance. Our research shows, however, that new innovations can spread like social media memes through insect colonies, indicating that they can respond to wholly new environmental challenges much faster than by evolutionary changes, which would take many generations to manifest.”
JOURNAL
PLoS Biology
Puzzle-solving behavior spreads through bumblebee colonies
Bees that learned from others were more adept and preferred the learned solution over alternatives
IMAGE: BUMBLEBEES CAN LEARN BY WATCHING A TRAINED BEE DEMONSTRATING ONE OF TWO WAYS TO SOLVE PUZZLE FOR A SUGARY REWARD, THEN COPY THE BEE TO SOLVE THE PUZZLE IN THE SAME WAYview more
CREDIT: DIEGO PEREZ-LOPEZ, PLOS (CC-BY 4.0, HTTPS://CREATIVECOMMONS.ORG/LICENSES/BY/4.0/)
Bumblebees learn to solve a puzzle by watching more experienced bees, and this behavioral preference then spreads through the colony, according to a study publishing March 7th in the open access journal PLOS Biology by Alice Dorothy Bridges and colleagues at Queen Mary University of London, UK.
Social animals like primates are skilled at learning by watching others, and previous work has shown that individual bees can learn tasks in this way, but it remained unclear whether these new behaviors would then spread through the colony. To investigate, researchers tested six colonies of bumblebees (Bombus terrestris) using a puzzle box that could be opened by rotating a lid to access a sugar solution. The bees could rotate the lid either clockwise or anticlockwise by pushing one of two different colored tabs.
The researchers trained bees to use one of these two solutions and then released these ‘demonstrator’ bees into a foraging arena alongside untrained bees and filmed them over a period of six to twelve days. Foraging bees with a demonstrator opened more puzzle boxes than control bees, and used the same puzzle solution that the demonstrator had been taught 98% of the time, suggesting that they learned the behavior socially rather than stumbling upon a solution themselves. In experiments where multiple demonstrators were each taught a different solution to the puzzle, untrained bees initially learned to use both methods, but over time they randomly developed a preference for one solution or the other, which then came to dominate in that colony.
The study is the first to document the spread of different behavioral approaches to solving the same problem in bees. The results provide strong evidence that social learning is important for the transmission of new behaviors through bumblebee colonies, as has previously been shown in primates and birds, the authors say.
Bridges adds, “These results in bumblebees, which are tiny-brained invertebrates, echo those previously found using similar experiments in primates and birds - which were used to demonstrate the capacity of those species for culture.”
Bees feeding from a puzzle box opened by pushing the blue tab
CREDIT
Alice Bridges (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)
Citation: Bridges AD, MaBouDi H, Procenko O, Lockwood C, Mohammed Y, Kowalewska A, et al. (2023) Bumblebees acquire alternative puzzle-box solutions via social learning. PLoS Biol 21(3): e3002019. https://doi.org/10.1371/journal.pbio.3002019
Author Countries: United Kingdom, China
Funding: This study was funded by an Engineering and Physical Sciences Research Council programme grant, “Brains on Board” (ref. no. EP/P006094/1 to L.C.) and a Queen Mary University of London PhD studentship (to A.B.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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