A handful of foragers return home early one morning, their stomachs heavy with nectar. They have found a good source of food, but it will take more honeybees to collect it all.
Inside the hive a worker suddenly charges at a bee, pushing with her head and grabbing with her feet. She jumps on top of the bee and shakes her abdomen up and down. The bee responds to this strange behaviour by walking off to the hive entrance. There she will watch the waggle dances on the propolis dance floor and join the foraging efforts of her sisters.
The worker had demonstrated the dorsoventral abdominal vibrating dance or DVAV, a dance to recruit more bees to forage during a sudden or plentiful flow of nectar.
The DVAV might also be used on a queen bee to make her move towards the entrance when it is time to swarm.
This week in my winter study post it’s all about the social network. Honeybees have evolved a complex social network that involves communicating through dance, food and scents.
1 Trophallaxis (food sharing)
Unlike beekeepers who chat over tea and cake, bees exchange food and communicate by regurgitating into each other’s mouths. This makes me very thankful to be a beekeeper and not a bee!
Food sharing, or trophallaxis, is when two worker bees share the crop content (a mix of nectar and other substances) in their honey stomachs, which results in an exchange of information about each other and about the colony. The clearest account I have read of trophallaxis is given by Celia F Davis in The Honey Bee Inside Out (pages 106–7), making a potentially confusing topic actually simple to understand:
‘It starts with one worker begging for food or another offering it. A begging bee pushes its proboscis [tongue] towards the mouth of another bee. The other bee then opens its mandibles, pushes its proboscis forward and regurgitates a drop of nectar from its crop, which the begging bee takes. An offering bee will regurgitate a drop of nectar and offer it to another bee. The result of this is that the crops of adult workers throughout the colony will contain the same mix of nectar and other substances at the same concentrations.’
Celia F Davis. The Honey Bee Inside Out
This method of food exchange is very rapid. Studies found that coloured or radioactive nectar fed to a few workers was spread to more than half the workers in the colony within 24 hours.
What’s the point of trophallaxis? Well, it gives each bee the ‘common colony stomach’, says Davis, so that they all have the same smell. This is how bees from the same colony can recognise each other; for example, guard bees can recognise returning foragers as members of their colony. It also ensures that ‘all the bees in the colony have a continuing appreciation of the quality of incoming nectar and pollen sources and their abundance in the colony’, which in turn can affect:
- foraging behaviour
- brood rearing and division of labour between house (inside) bees
- queen’s rate of egg laying
Trophallaxis and other methods of communication
Trophallaxis can play a part in the exchange of scent (chemical) messages, when bees touch antennae during nectar sharing. Food sharing can also happen during the waggle dance when the dancer gives a taste of nectar to another bee to show how good it is.
Honeybees are very good choreographers and they use different dances to communicate including the DVAV, round dance, sickle dance and, everyone’s favourite, the waggle dance.
The waggle, or wagtail, dance is a figure of eight movement with a little waggle in the middle. It is performed by foraging honeybees who find a good source of forage (trees or flowers) and then fly home to tell everyone else.
It goes something like this…
The bee walks in a straight line waggling her bottom and buzzing her wings. She then turns and loops back to where she started. She walks along the straight line again, waggling her bottom and buzzing her wings, then loops back in the other direction creating a figure of eight on the dance floor. The straight line indicates the direction of the food and the number of waggles indicates the distance.
In the bee world, the vertical face of the honeycomb (imagine sections of comb hanging down inside the hive) represents the sun, and the angle of the straight line to the vertical indicates the position of the trees or flowers to the sun. For example, if the straight line is run at a 60 degree angle, then the food source is 60 degrees to the sun.
As the sun is always moving across the sky, the dancer calculates the sun’s movement by adjusting the angle of her dance every four minutes by one degree to the west.
If my clumsy attempt to describe the waggle has left you confused, then Sir David Attenborough explains it excellently in the BBC’s Trials of Life. Finding the way: waggle dance.
The round dance is performed as a simple loop. It doesn’t give directions like the waggle dance and simply says ‘Go get it!’ The round dance is used when a food source that has a particularly high sugar content is not far from the hive, for example: a field of oilseed rape, other hives or an M&M factory! There must have been a lot of excited French bees doing the round dance last year after discovering vast quantities of blue sugar syrup nearby.
The sickle dance is a figure of eight without the waggle in the middle. It is somewhere between the round dance and the waggle dance and it is used when the distance to the forage is somewhere inbetween. It says, ‘around the corner and up the next street’.
There are other dances that have been observed inside the hive.
- Jostling dance: a prelude to the waggle dance. Foragers returning from a successful trip will run and push other bees to let them know they are about to do the waggle dance.
- Spasmodic dance: a variation on the jostling dance that includes food sharing, and presumably gives the same message.
- Trembling dance: while the DVAV dance recruits more foragers, the trembling dance seems to recruit more receiver and storage bees to help foragers unload nectar and pollen. Davis says: ‘A bee runs about on 4 legs and twitches and trembles. If it meets a bee performing a wagtail dance, it head-butts it and briefly pipes.’
Apparently, the time it takes for a forager to unload her nectar influences the type of dance that is performed. If the forager takes 20 seconds or less to unload nectar, the DVAV dance is performed to recruit more workers to forage. However, if the forager takes 40 seconds or more to unload, then the trembling dance recruits more bees to help process nectar being brought into the hive.
The dance language of bees is varied and complex, and care should be taken in the interpretation, says Davis. For example, the trembling dance can also be a request for grooming. Other dances, like the DVAV dance and the buzzing run, have also been connected with swarming.
The buzzing run is where a bee runs in a straight line while buzzing its wings and collides with another bee – they touch antennae, buzz and run off to collide with more bees. The dance has a cascading effect across the hive with bees buzzing, running and colliding until they swarm. Davis says that the buzzing run is performed again by the swarm before flying off to its new home, and it is then sometimes called the break dance.
As an aromatherapist, I envy bees living in a world of aromas. The hive is like a perfume factory with a scent for every occasion, including: to communicate, to stimulate and suppress behaviour, to coordinate activities, to attract and to alert among many other things.
These important scents are pheromones – chemical substances that are secreted to affect a specific reaction. A helpful definition of pheromones was coined in the 1950s:
‘Pheromones are substances which are secreted to the outside by an individual and received by a second individual of the same species in which they release a specific reaction which may be behavioural, developmental or physiological.’
The chemicals are made in glandular cells and secreted by glands, specifically exocrine glands, that secrete substances outside the body. (Humans, for example, have an endocrine system – endocrine glands – that secrete chemical substances such as hormones inside the body. A very basic biology lesson!)
In the hive, pheromones are released by queens, workers, drones, brood and even comb. As many pheromones used by honeybees have been covered in other posts, for the purpose of this part of the syllabus here’s a quick summary:
There is so much to explore about the world of pheromones that I may revisit this in another post.
Finally, a form of communication largely used by queen bees, although sometimes used by workers, is piping and it can be associated with swarming. Virgin queen are known to pipe inside their cells and it is thought that they are warning their sister queens-in-waiting that they have a rival for the throne! After emerging from her cell, an unmated or mated queen also makes this noise by resting her thorax on the comb and vibrating her powerful flight muscles.
Visit my blog index for more winter study posts.
A great revision post from Emily Heath of Adventures in Beeland: 5th Honeybee behaviour revision post: bee communication
Mid Buck Beekeepers Association Blog’s excellent revision notes for BBKA module 6
Celia F Davis. The Honey Bee Inside Out. Bee Craft Ltd, ISBN-10: 0900147075
Ted Hooper. Guide to Bees and Honey. Northern Bee Books, ISBN-10: 1904846513
The knowledge of bees gives rise to interesting possibilities in AI.
In a world where so many variables are in motion and change a map based on time and space requires an “axis mundi” a dependable slow changing variable upon which all over variables can be measured against. For the bees the axis mundi is a locus in their nest, they will use this point to orientate themselves and communicate their knowledge to their fellows, a shared constant in their hive-mind wordview. The sun is too changeable to provide an axis mundi, something else has to be the axis mundi. In Stonehenge they have an axis mundi which then acts as a point of reference to build a calender against the stars, sun, moon, landscape and positions of other megalithic sites. Hope I made sense.
I think my bee-size brain can just grasp it! Although, if they can create an AI as clever as the hive mind then the possibilities are incredible… I’m simply amazed that during the waggle dance a bee can not only indicate the direction of the flower in relation to the sun but also compensate for the movement of the sun between visiting the flower and flying back to the hive. Breathtakingly incredible!
How fascinating – I’m amazed how they share food. To me it seems an incredible waste of time and energy but I obviously don’t have a bee brain.
Last week I was standing in front of one of my hives staring inside the entrance with binoculors (I was about 2 metres away and with the naked eye can see bees, pollen and a lot of movement, but not much detail). I saw a bee land on the landing board and rush in about 1 or 2 inches into the hive and then wiggle like mad on the bottom board. I thought the waggle dance was done on the comb so this confused me. Actually, after reading your post it still does confuse me. I had no idea how many different dances bees had. Any thoughts on why a bee would have what looked a lot like a siezure on the bottom board?
The waggle dancers share food because it gives the watching foragers a clue of what they are looking for, how it tastes and smells. In scientific experiments using robot waggle dancers, the foragers attacked the robot when it failed to give them a nectar sample.
The sharing of food also helps give the colony a common smell, which is helpful for bees in distinguishing between hives and cutting down on forager drifting.
I couldn’t have explained it better, thanks Emily! And as someone who is mathematically-challenged I found the waggle initially confusing too Laura, although the BBC video cleared it up for me 🙂
Bee speak, it is interesting to learn. I really like your first image, Emma. The bee is being a very cooperative girl.
Thanks, Donna! She was being very cooperative on a rare sunny day last year, though I’ve noticed our bees are quite curious about the camera 😉
Fantastic post, you have really brought the dances to life. Did you do all the dance graphics yourself? They are so clear and easy to understand.
About the last ‘Honeybee pheromones’ graphic – there have been some recent discoveries on 2-heptanone, and the latest research indicates that it is unlikely to be an alarm pheromone, as first thought. Until as recently as 2011, it was thought to be mainly used by guard bees to ward off robbers or used by foragers to scent-mark recently visited and depleted flowers.
However, 2012 research by a team of researchers from Greek and French organisations in collaboration with Vita (Europe) Ltd, the UK-based honey bee health specialist, has contradicted these theories. Their work uncovered for the first time that the 2-heptanone compound has local anaesthetic properties. Independent tests have verified these findings.
Amazingly, honey bees can use their mandibles to bite smaller parasites like varroa mites and wax moth larvae, in the process secreting 2-heptanone into the bite wound. The compound’s paralysing effect works for up to nine minutes, giving the time bee to eject the enemy from the hive – a particularly effective defence against pests which are too small to sting.
The ‘grooming’ behaviour which some beekeepers believe helps ‘hygienic’ honey bees to control varroa populations may reveal itself to be biting behaviour.
For more on this discovery:
BBKA News, No:210 – February 2013, ‘In the News: Secrets of the Honey Bee Bite Revealed’, p17.
HoneyBeeSuite, ‘Watch out! They bite!‘, Rusty, 17 Oct 2012
PLOS ONE journal, ‘The Bite of the Honeybee: 2-Heptanone Secreted from Honeybee Mandibles during a Bite Acts as a Local Anaesthetic in Insects and Mammals’, 16 Oct 2012
The Telegraph, ’Bees can bite as well as sting‘ , Louise Gray, 17 Oct 2012
I’m not sure whether the latest findings discredit the previous beliefs on warding off robbers and scent-marking or not (although some of the articles I’ve read suggest they do). You might want to check this on the BBKA forum. I’m sure mentioning the latest research would get you extra brownie points in the exam though.
That’s amazing, Emily, thanks! Hopefully I’ll remember all that for the exam. Just shows how much there is to discover about these amazing creatures. Next up is 6.7 the behaviour of foraging bees and work methods in the field including orientation – difficult to find much on this specifically in the books, although hoping I don’t have to write an essay for every part of the syllabus as there is quite a bit of crossover on some points.
The Bucks notes should help. Also ‘Plants and Honey Bees: their relationships‘ by David Aston & Sally Bucknall (2004) is a good one on foraging, I could lend you it if you like. Maybe I could swop it for The Honey Bee Inside Out, think that has some info on diseases?
That sounds great, Emily. I’ll bring along The Honey Bee Inside Out tomorrow. Still deciding whether or not to go to talks on Saturday as having such a busy week, this Saturday may be my only time to catch up on jobs. Although wouldn’t mind hearing Karin’s talk in the morning.
Wow, some great comments here – thanks. Visitors around this Sunday so not much blogging doing – although will catch up with everyone this evening 🙂
I learned something new about scenting! I have seen many bees stick their abdomen up in the air, but I did not know the exact reason, now I do. 🙂 How do you get access to all the BBKA modules? Are they available online with a membership? They have great information.
BBKA exams, modules and assessments are available here: http://www.bbka.org.uk/learn/examinations__assessments
You can download the syllabus and reading list, and there is also a correspondence course, although there aren’t module notes – Emily and I are just posting our own revision notes as we go along!
Thank you for the link and for taking the time to post your notes! They are very helpful and I have learned a few things from reading them. Here is the US it is a little different to become a master beekeeper, you have to go through a university rather than through a beekeeper’s association. I’m actually not too concerned with becoming a master beekeeper myself, but I do enjoy reading the material and learning more about bee behavior and management techniques.
Wow, that was an amazing post
Thanks! Just hope I remember everything for the exam 🙂
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