In this blog, I'll explore the "how" and "why" of honey production, including some fascinating details of honeybee life and the vital role pollinators play in nature.
Only honeybees make honey. It has been a unqiue source of sweetness for centuries - before there was Tate and Lyle there was honey. It's still a valuable human food today and as beekeepers, you can buy honey from us.
But hang on - honeybees have been around for millions of years. Much as we love it, they don't produce it for humans. So, why do they make honey?
By transforming nectar into honey, honeybees create an energy rich food store for their colony.
This blog explains how and why bees make honey and the biology behind it. It also explains the indispensable role bees of all kinds play in supporting biodiversity.
TABLE OF CONTENTS
WHY DO BEES MAKE HONEY - HONEY'S ESSENTIAL PURPOSE
Bees are vegetarians. They feed on the nectar and pollen produced by the flowers of flowering plants. They use the sugar in nectar to power everything they do. Think of nectar as a bee's energy drink.
Like other bees, honeybees rely on nectar. Unlike other bees, honeybees are active all year round. But from around November through to February, there are no flowers.
So, what do honeybees eat in winter? Honeybees eat honey.
Honey is a concentrated sugar solution. Sugar is packed full of energy so honey is a store of concentrated energy.
Honey isn't some handy by-product - it's a way for honeybees to store summer's energy into the winter. It's a matter of life and death.
HONEY - A YEAR ROUND COLONY FOOD SOURCE
During late autumn and winter there is a "skeleton crew" of about 10,000 bees inside a hive. They keep the hive ticking over - clustering around the queen to protect and keep her warm. They use their honey to keep themselves going during the cold, flowerless months.
More importantly though, they use honey to generate heat.
In the depths of winter, honeybees do something amazing - they start to get ready for spring.
They increase the temperature inside the hive from around 25 to 35 degrees C. This is warm - in fact, it's close to our own body temeprature. This is the temeprature they need to raise their young.
The bees vibrate their flight mucles to generate heat. It takes a massive amount of energy to produce the heat they need. This energy comes from honey and bees need at least 20kg of it to see them through the winter
The queen, who has laid few if any eggs over winter, starts to lay eggs again. They will develop into new bees.
These bees will be ready to start visiting flowers as soon as they appear in spring.
Unlike all the other species of bee, the honeybee's ability to store honey means that they don't need to hibernate. They get a head start in spring.
This is a major evolutionary advantage.
HOW BEES MAKE HONEY - STEP BY STEP
Honey starts out as nectar which is sugar - mainly a sugar called sucrose - dissolved in water.
Perhaps surprsingly, this is the same sugar we get from sugar cane and sugar beet. It's the sugar people put in tea, fizzy drinks and jam.
The amount of sugar in nectar varies from species to species. Sometimes it's as much as 70%. Even with 30% water there's way too much water for it to keep. Just like a sugary drink, the nectar will ferment if kept too long.
Honeybees have evolved a way to process nectar so that it can keep forever (almost).
At it's simplest, the process of honey production involves:
gathering the nectar
adding enzymes to it
evaporating water from it
storing the finish product in honeycomb
WORKER BEES - THEIR ROLE IN HONEY PRODUCTION
All the work in a hive is done by female worker bees. This includes collecting nectar and turning it into honey.
At its summer peak, a honeybee colony has a vast force of perhaps 30,000 workers all working to gather nectar. They can visit thousands of flowers in a day. Beekeepers call this activity foraging.
Bees are built for nectar collection. Each foraging bee sucks up nectar with straw-like mouthparts called the proboscis (No.1 in the diagram).
If they don't want to digest it to power their own flight, they store the nectar in their honey stomach (No. 29 in the diagram).
The honey stomach is a holding tank that allows the bee to transport nectar back to the hive.
FORAGING FOR NECTAR - THE START OF HONEY PRODUCTION
Foraging honeybees don't randomly visit every flower they come across (like butterflies and flies). They are much more efficient with their time and energy.
Worker bees learn quickly and have excellent memories. A forager rapidly learns the colour and shape of a flower. If it gives a good supply of nectar (or not) she will remember it and visit it repreatedly. This is called flower constancy.
Vision is not the only sense at work. A honeybee has an amazing ability to differentiate and remember scent. Presented with 1,816 scents, honeybees can discriminate between 1,729 of them.
As she gets closer to the flower, as well as colour, shape and scent, the bee recognises other features:
texture
electrical charge
humidity
temperature
taste
ENZYMES AND EVAPORATION - TURNING NECTAR INTO HONEY
Having found the flower she wants, the worker sucks up nectar with her proboscis. As she does so, she adds an enzyme.
The enzyme breaks down the sucrose into two simpler sugars - glucose and fructose. This happens in the bee's honey stomach on the way back to the hive.
At the hive, the returning bee passes the nectar to one of her sisters. This worker, called a receiver bee, adds another enzyme which reacts with the nectar's glucose to produce hydrogen peroxide.
The hydrogen peroxide helps destroy bacteria in the nectar - one step on the way to helping it keep.
The next step is to get rid of water.
Individual bees strop the nectar. They draw up a drop of nectar and run it along their mouthparts. They expose it to the air - before swallowing it again. They do this many times - making the nectar more and more concentrated.
But it needs to be even more concentrated. This stage uses the honeycomb itself.
ABOUT HONEYCOMB - WHERE HONEY IS RIPENED AND STORED
Honeycomb is made with wax secreted by the bees themselves. It has many functions including its use in honey production and storage.
When concetrated enough, the bees put the liquid they have been stropping into individual honeycomb cells. In June, July and August whole areas of comb are filled with this sugary mixture.
Evolution has ensured that the bees make cells pointing upwards slightly - so that the still runny mixture doesn't dribble out!
The worker bees fan the combs with their wings to encourage more evaporation. Beekeepers call this ripening the honey. Working night and day, the hive hums with the sound of thousands of beating wings.
When the water content is about18% the nectar has become honey.
With so much sugar (82%) things like yeast can't grow. Unlike nectar, the honey will store in the comb without fermenting.
Finally, the bees seal each honey filled cell with a beeswax cap. Just like a lid on a jar, the cap keeps out moisture and dirt (from lots of honeybee feet).
The bees have used the properties of glucose and fructose, at hive temperature, to produce a concentrated mixture. Through their work, they have produced a supersaturated sugar solution - which we know as honey.
THE BIGGER PICTURE - FORAGING, POLLINATION AND BIODIVERSITY
So far, I've described things from the honeybees' perspective BUT this story has another important player - flowers.
Plants can't move and mate with each other like animals can, so flowering plants use bees (and other pollinators) to move about on their behalf. In his brilliant book "Bees" Christopher O'Toole calls this "mating by proxy".
Nectar is the bribe that flowers offer bees to get them to come and visit.
The bees come foraging for nectar and get covered in pollen. They eat pollen too - but that's another story.
Pollen contains the male genes of a plant. The pollen covered bee carries these genes to another flower of the same species where, hey presto, they meet up with that flower's female genes. The plant has been pollinated (fertilised). It can now make seeds and bear fruit.
READ MORE: What's in a flower and why does it matter?
A honeybee colony produces about 300kg of honey in a season. This takes about 7.5 million flower visits. That's a lot of pollination!
Honeybees are the focus here but there are at least 20,000 other kinds of bees in the world - more than all the species of birds and mammals combined. There are about 270 in the UK alone. Each species has its own special foraging relationship with flowers.
Bees are keystone species in ecosystems. They are essential to the pollination of the flowers, trees and shrubs we see around us. They also pollinate hundreds of our crops.
CONCLUSION
For anyone that likes honey, the how and why of honey production is an interesting side issue.
For the honeybee, the answer to the question "how and why do bees make honey" is much more serious. It means a winter survived and a colony ready for another spring.
Honey can be stored for years because:
It's high sugar concentration stops yeast growing
Hydrogen peroxide has an antimicrobial action - bacteria can't grow
Dirt , air and water are kept out by a beeswax cap
Honeybees make this amazing stuff through an incredible mix of chemistry, physics and teamwork plus some tailor-made biology.
Most importantly, without them and thousands of other bee species, the diverse, productive and colourful world we know today would not exist.
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References:
Diagram of the internal anatomy of a honeybee - Bee Anatomy at Ask a Biologist Arizona State University
Information about the chemistry of honey - The Honeybee Around and About by Celia F. Davis (2019) Beecraft Ltd
Information about the composition of nectar - Nectar composition and concentration of 26 species from the temperate forests of South America by Chalcoff, Aizen and Galetto in the Annals of Botany
Relevant books about bees:
Bees: A Natural History by Christopher O'Toole, (2013) Firefly Books
The Buzz about Bees : Biology of a Superorganism by Jugen Tautz (2008) Springer
Thanks to:
Photographs of honeybees courtesy of Gilles San Martin on Flickr under a Creative Commons Licence
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