Honeybees change nectar from flowers into honey, to make food for themselves. The average hive stores 9–14kg/20–30lb of honey by the end of the year. This represents a huge joint effort because a single worker bee produces only half a teaspoon of honey in her whole life. It takes nectar collections from around 2.6 million flowers, involving bee flights totalling around 88,000km/55,000 miles, to produce just 450g/1lb of honey.
The dates in this chapter are for temperate countries in the northern hemisphere. Adjust them by six months for temperate countries in the southern hemisphere.
Only a few of the 25,000 or so species of bee make honey, and most of these produce only tiny amounts.
Honeybees inhabit every continent except Antarctica. Apis melllifera is the most common type in Europe, the US, Canada and Australia. Honeybees live in large colonies and store a lot of honey. In contrast, the bumblebee (Bombus bombus) lives in a small colony that stores a tablespoon at most.
Honeybee varieties differ in honey-making ability, honeycomb colour and building, hive-care, immunity, tendency to swarm (form a new colony), multiplication, appetite and character. The most popular are Italians (brown-and-yellow-striped), Carniolans (black or grey) and Caucasians (grey). Thanks to migration and importation, though, many honeybees are mongrels today.
From here on I’ll generally call honeybees simply ‘bees’.
A bee colony – or family – consists of:
• A queen bee – the only fertile female. She lays eggs, keeps the colony happy, is the longest bee and lives 18 months on average, although she can survive up to six years.
• Up to 30,000-60,000 worker bees – small infertile females that groom and feed other bees, maintain the hive, collect nectar, pollen, propolis and water, and make honey. A spring- or summer-born worker lives six weeks at most, an autumn-born one six months.
• Several hundreds or thousands of drones – fertile males that are shorter and stouter than the queen, have large eyes but no sting, wax glands or pollen baskets, and live eight weeks at most.
Wild bees build nests in trees, logs, hedges, cliffs or walls. Removing their honey destroys their nest. Over the centuries, people have designed reusable nests – ‘hives’ – that enable harvesting of honey without bothering the bees too much.
Worker bees fill the hive with vertical, double-sided sheets of wax honeycomb. Each side consists of hexagonal cells, most of which are 5–7mm/1.5–¼in across. These receive worker eggs and store the colony’s food: honey, pollen and bee bread, a mixture of pollen, nectar, saliva and microorganisms. Slightly larger cells receive drone eggs, and very large, thimble-shaped ones receive queen eggs.
Many beekeepers supply honeycomb starter sheets so that bees don’t need to make so much wax and, as a result, have more energy to make honey. These sheets encourage workers to build relatively few drone cells, whereas honeycomb built entirely by bees has more drone cells. This triggers the queen to lay more drone eggs, and it’s said that having more drones makes a colony happier.
Honey is the bees’ main source of carbohydrate, pollen their main source of protein. But both contain many other vital nutrients.
As a young adult, the queen couples with up to 40 drones. These then die, but she stores their semen. In April and May, the queen lays up to 3,000 eggs a day, each smaller than a grain of rice. Her fertilized eggs become workers and queens, while the unfertilized ones become drones.
After mating, and for the rest of her life, the queen’s mandibular glands secrete a cocktail of 30 pheromones into her mouth. The scent of this ‘queen substance’ attracts workers to lick and feed her and to pass it on to other bees, which keeps them calm and cooperative.
The high-grade nourishment she needs comes from royal jelly, also called brood food or bee milk. This sweet, fatty, creamy-coloured substance contains whitish secretions from young workers’ mandibular glands and yellowish protein-rich secretions from their hypopharyngeal glands.
Three days after being laid, the eggs hatch into larvae (grubs). These produce brood (or ‘feed-me’) pheromone whose scent stimulates workers to feed them. All larvae receive royal jelly at first.
Four days after hatching, workers choose a larva’s food according to its cell size. Larvae in worker and drone cells stop receiving royal jelly and instead get bee bread, which is less nutritious. Larvae in queen cells continue to receive royal jelly – in fact, their cells are flooded with it – and this makes them develop into queens.
Six days after hatching, a larva spins a cocoon, and workers then seal its cell with a wax lid (capping), ready for pupation. During this stage, which lasts 10 days for a worker, 13 for a drone and five for a queen, a wondrous metamorphosis turns the larva into an adult bee. The young adult then chews through its cocoon and cell and emerges into the hive.
Up to 2,000 new young adult workers emerge each day from the average hive.
From one to seven days old, a worker is a ‘nurse bee’. She cleans the hive. She solicits food by sticking out her proboscis (‘tongue’), encouraging older bees to offer regurgitated honey. Later, she feeds herself from honey and bee-bread stores.
When pollen protein has matured her mandibular and hypopharyngeal glands, she feeds royal jelly to all young larvae and older queen larvae. She feeds older worker and drone larvae with bee bread. And she grooms and feeds young adults.
From 7–12 days, she is a ‘house bee’. Her abdominal wax glands begin producing pinhead-sized scales of wax. Other bees collect her wax, soften it by chewing, then use it to build honeycomb and cap cells containing mature larvae or ripe honey. The latter is honey that has been dehydrated until its water content is about 20 per cent, so it resists fermentation. Once its cell is capped, its water content falls to about 18 per cent.
A house bee also strengthens, waterproofs and disinfects the hive, including the honeycomb, with propolis (see page 58).
From 12–14 days, a house bee converts nectar into honey. To do this, she accepts nectar from foragers, then for 30 minutes or so regurgitates a drop at a time, allowing invertase, an enzyme now produced by her hypopharyngeal glands, to break down sucrose into glucose and fructose. She holds each drop between her jaw and proboscis to encourage dehydration in the hive’s warm air. She puts it down for several hours to allow further evaporation. Then she or another house bee puts it into a cell.
She also collects pollen pellets deposited by foragers, moistens them further with saliva and nectar, puts them into a cell and packs them down by head-butting. She covers pollen-filled cells with honey. Bacteria (lactobacilli) from secretions she has added to the honey ferment the pollen into bee bread. She also ejects debris from the hive.
From two weeks, a house bee dehydrates honey in uncapped cells by fanning her wings. And she guards the hive’s entrance by sniffing other bees’ scent. If it’s foreign, she produces alarm pheromone to muster help.
At three weeks, she becomes a forager, flying out to collect nectar, pollen, propolis and water. She flies up to 1.6–3.2km/1–2 miles from the hive, sometimes three times as far, letting her scent receptors guide her to enticing scents, and her eyes to attractively coloured flowers. On a good dry day she might make 20 trips, each time visiting up to 1,000 flowers and sucking nectar through her proboscis and via her mouth into her honey sac (the expanded end of her gullet). She can feed on nectar by opening a valve in her honey sac to let some enter her stomach. She collects pollen by brushing it from her body with her middle legs, adding saliva and nectar to form tiny pellets, and packing these into hairy baskets on her back legs. She carries home 0.06g/0.002oz of nectar and 20mg/0.0007oz of pollen, equalling half her bodyweight. She collects water from ponds or other sources, or by choosing watery nectar, and carries it in her honey sac. She also collects propolis.
Once home, she lets other foragers smell and sample her nectar and pollen so they can decide whether to visit her sources. She regurgitates nectar for younger honeybees to ripen, and deposits pollen and propolis. She dances to alert other foragers to good nectar sources. A circle dance – first anti-clockwise, then clockwise – indicates nectar and/or pollen within 10m/11 yards. A waggle dance – half a circle one way, then a turn and a straight run while wagging her tail, then half a circle the other way – indicates they are more than 91m/100 yards away. The direction of the straight run indicates their location relative to the sun; the frequency of waggle runs defines their distance more precisely; her vigour communicates their quality.
Workers keep the hive at 28–35ºC/82.4–95ºF. They warm it by digesting honey and pollen, huddling together and shivering, and they cool it by distributing water and by fanning their wings near the entrance. They also wander around or rest, often breaking at midday when there is a lull in nectar production.
Bees fly from the hive to collect nectars and pollens for food. Certain flower scents are especially attractive to foraging bees, and they particularly like blue and purple flowers. Indeed, a worker’s two complex eyes, each with nearly 7,000 little lenses, are particularly sensitive to blue, purple and ultraviolet (UV) light. Nectar reflects UV light, and a worker detects this as a dark area in a flower. The other three of a worker’s five eyes are simple eyes that sense polarized sunlight. Bees navigate by recognizing the landscape, and sensing the sun’s position and the Earth’s magnetic field.
A forager exhibits ‘flower fidelity’ by visiting only one type of flower per trip. Other bees in the colony may visit different types. Different nectars and pollens offer different proportions of their contents, encouraging a healthy diet.
Nectar is a powerful attractant produced from sap by glands in a flower’s nectaries. A hive’s honey store is built up from many individual loads of nectar.
Honeybees have a short proboscis, so favour easily accessible nectar: for example, from flowers with a single ring of petals, multiple small flowers or a large trumpet.
Nectar is a watery solution of sugars, plus traces of acids, minerals, proteins, enzymes and various aromatic and other substances. Plants make sugars by photosynthesis. This involves converting water and carbon dioxide into oxygen and sugars using energy from light absorbed by the green plant pigment chlorophyll. Foragers prefer sweeter nectar because house-bees accept it more readily.
Nectar sugars vary in type and proportion according to a plant’s species, and the soil, climate, weather and season. Sugars form 40-45 per cent of nectar by weight on average, but the proportion varies in different nectars. For example:
| • Primrose | 5 |
| • Plum | 15 |
| • Apple | 25 |
| • Lime | 35 |
| • White clover | 40 |
| • Kale | 50 |
| • White horse-chestnut | 70 |
| • Marjoram | 76 |
Nectar volume varies with flower species, soil moisture, air humidity and temperature, and rate of nectar flow. Nectar flow rises at certain times of day according to a flower’s size and species. Temperature extremes can reduce or halt nectar production; warm weather increases it. Many wild flowers are excellent nectar producers.
This table (right) gives examples of the range of amounts of honey a colony of bees can make from 1 acre/2.5 hectares of land growing one type of plant:
Bees not only produce honey from nectar but also from honeydew, a sweet, dark or greenish liquid or crystalline substance excreted by aphids, leafhoppers and scale insects onto leaves or branches after eating sap. It’s called honeydew because its droplets glisten like dew. Many honeys are made from both nectar and honeydew.
The manna referred to in the Bible was almost certainly honeydew.
The nutrients in pollen include proteins (which strengthen bee-wing muscles), carbohydrate (which builds fat stores to provide energy for flying and warming the hive) and fats, vitamins, minerals and plant pigments (which promote general health).
Bees need pollens from a range of plants for optimal health. This is because the concentrations of nutrients vary in different plant species. Also, different plant pigments boost immunity in different ways.
Pollen can be yellow, orange, red, brown, black, green and even blue.
| PLANT | KG HONEY PER ACRE | LB HONEY PER ACRE |
| Tansy (phacelia) | 82–682 | 180–1,500 |
| Black locust | 364–545 | 800–1,200 |
| Lime | 364–500 | 800–1,100 |
| Rosebay willowherb (fireweed) | 364 | 800 |
| Coriander | 91–159 | 200–350 |
| Clover | 91–136 | 200–300 |
| Lemon balm (melissa) | 68–114 | 150–250 |
| Milkweed | 54–114 | 120–250 |
| Echium | 91 | 200 |
| Mint | 68–91 | 150–200 |
| Heather | 45–91 | 100–200 |
| Borage (starflower) | 27–73 | 60–160 |
| Cornflower | 45–68 | 100–150 |
| Thyme | 23–68 | 50–150 |
| Willow | 45–68 | 100–150 |
| Lavender | 32–54 | 70–120 |
| Hawthorn | 23–45 | 50–100 |
| Sunflower | 14–45 | 30–100 |
| Valerian | 27–32 | 60–70 |
| Elderberry | 9–27 | 20–60 |
| Goldenrod | 11–23 | 25–50 |
| Aster | 14–23 | 30–50 |
| Coltsfoot | 11–16 | 25–35 |
| Opium poppy | 9–14 | 20–30 |
A colony’s activity varies with the seasons. The nearer the equator, the more even are the nectar and pollen supplies and therefore the honey production.
The only bees to survive winter are the queen and up to 10,000 workers. Hopefully, the colony has enough stored honey and pollen to feed them until enough early nectar and pollen is available. If not, the beekeeper can supply honey and pollen stored from the previous year in case of need.
Food supplements are second best. Patties of protein-rich substitute food made from soybean meal, milk, minerals, vitamins and high-fructose corn syrup are much better than sugar syrup. But even they are not nearly as nutritious as the bees’ own honey and pollen.
Longer days, rising temperatures and good food supplies enable the queen to start laying, so plenty of workers will be available to collect nectar and pollen. Primed by good supplies of early nectar, the workers build honeycomb ready to store food for the growing brood. Supplies of protein from early pollens such as from coltsfoot and hazels are vital for healthy larvae.
Sources of nectar and pollen include certain trees (including willows and fruit trees), crops (such as avocado, borage, cotton, echium and winter-sown oilseed rape – canola), weeds (such as clover, coltsfoot and dandelion) and garden and wild plants (such as blackberry, crocuses, daffodils, elderberry, manuka, rosemary and tansy).
Most collected nectar and pollen feeds the growing colony. If nectarflows are very good, though, beekeepers can harvest surplus honey. As spring-flower nectar and pollen supplies dwindle, some beekeepers move their hives to areas that will be rich in summer flowers.
By mid-May, egg-laying is at its height.
The average hive population peaks in mid-July, with up to 50,000 workers and up to 1,000 drones, plus a brood of 6,000 eggs, 9,000 larvae and 20,000 pupae. As brood-pheromone production by larvae is at its height, foragers have ample stimulation to collect food. Summer plants tend to have particularly sugary nectar that quickly builds honey stores. Sources include certain crops (such as blueberries, borage, buckwheat, lucerne – alfalfa, and spring-sown oilseed rape), weeds (such as dandelion, milkweed, purple loosestrife, rosebay willowherb or ‘fireweed’, sea lavender, smartweed, star-thistle, trefoil, and vetch) and garden and wild plants (such as aster, borage, goldenrod, heather, honeysuckle, lavender, melissa or ‘lemon balm’, sunflower and thyme).
Bees need plenty of nectar whose honey will remain runny for months in the comb and thus be easy to eat. Honey from certain nectars (such as aster, clover and oilseed rape) crystallizes within a few days and is difficult for bees to dilute and eat. If such nectars form the bulk of their spoils, bees may go hungry later in the year. Beekeepers harvest such honeys promptly so that they can remove it from the comb.
In some areas and in some seasons, late-summer nectar-producing flowers are scarce. Usually, though, a colony can store enough honey and pollen to sustain remaining bees through winter and get the new brood off to a good start in spring. If there is more than enough honey for the bees, beekeepers harvest some for themselves. If bees are making monofloral honey, beekeepers collect the surplus as soon as this nectarflow ends. Beekeepers in Scotland, for example, may transport their bees to moorland in later summer to collect nectar from heather.
The most northerly parts of temperate zones have few bee-friendly flowers from October to March. They include echium (second flowering), goldenrod, gorse (out for much of the year and visited mainly for pollen), heather and ivy. Falling temperatures make bees increasingly reluctant to forage, while shorter days reduce foraging time.
The queen lays fewer and fewer eggs. The last ones of the year become the workers that will raise the spring brood. To conserve food stores, workers kill remaining drones by starving them, pushing or excluding them from the hive or biting off their wings.
Some beekeepers wait until early September before removing their first honey of the year. Indeed, the US honey harvest traditionally begins on Labor Day (the first Monday in September). Two or more collections of surplus honey can usually be made each year, the last sometimes as late as in October, though some beekeepers make many more collections.
Short days prevent the queen laying eggs. The average colony shrinks to 10,000 bees at most. These stay active and eat the hive’s food stores. If there isn’t enough honey, or a beekeeper has taken too much, substitute food is vital or the colony will die.
If any nearby flowers blossom in January and the temperature is above 10ºC/50ºF, workers go out to forage.
If stored honey is very viscous, or has crystallized, bees dilute it with water before eating it.
Pollination enables a plant to reproduce itself by producing seeds. It involves the transfer of pollen from the anthers (male organs) of one flower to the stigma (female organ) of another of the same species.
Flowers produce nectar to attract bees and other insects (and animals) to pollinate them. As a bee collects nectar, pollen collects on her hairy body. Her flower fidelity means she visits flowers of the same species and inadvertently pollinates them at the same time.
Most insect-pollinated flowers can be pollinated by a variety of insects. White clover, for example, is pollinated by honeybees, bumblebees and solitary bees. Others rely on only one sort of insect: for example, cocoa flowers are pollinated only by midges. Certain plants are pollinated by other animals (such as birds and bats); wind (for example, cereals, other grasses, most conifers and many deciduous trees); or humans (for example, greenhouse melons). And certain crops, including broad beans and coffee beans, can self-pollinate.
However, honeybees are the main pollinators of many plants, including many crops (such as almonds, apples, avocados, blueberries, cherries, cranberries, lettuce, oilseed rape and sunflowers). In 2011, a United Nations Environment Programme report noted that bees help pollinate more than 70 per cent of those 100 crops that supply 90 per cent of the world’s food. In countries with a temperate climate, about a third of vegetable, fruit and nut crops, plus most wild flowers, depend on bee pollination.
A lack of bees limits the harvest from bee-pollinated crops. Some such crops, including almonds and blueberries, can crop without pollination, but this delays ripening; encourages damage by disease, poor weather, pests and pesticides; and produces fewer, smaller or seedless fruits.
All this has led to the vast industry of migratory beekeeping. Farmers pay beekeepers to transport bees sometimes thousands of miles to pollinate crops such as almonds, apples, blueberries, borage, field beans and oilseed rape. In the US, more than 2.5 million hives are rented to farms each year. One million, for example, go to almond orchards in California; 50,000 to blueberry fields in Maine; and 30,000 to apple orchards in New York State.
In recent years, bee numbers have declined steeply. Around a third of the bee population was lost in the US in 2007–2008. The number of bees in the UK has halved from the 1960s to 2012. Large losses have been reported in Egypt, China and Japan.
This is alarming because a third of our food comes from crops that rely mainly on bees to pollinate them. A lack of bees not only makes harvests small, unreliable and late, but wildflowers dwindle because there are so few seeds, and there is less honey for bees – and humans – to eat.
The death of the queen bee is associated with one in four colony losses, while ‘colony-collapse disorder’ in which a whole bee colony goes missing, presumed dead, accounts for about 7 per cent of losses in the US, rather fewer in Europe.
The subject of colony collapse is much debated and theories abound as to the cause. One suggestion is that lead-containing crystals in bees’ abdomens sensitize them to the growing number of electromagnetic fields surrounding us, influencing their behaviour and encouraging disease. Another is that infestation with Varroa destructor mites, or infection with viruses, fungi or bacteria, makes bees more vulnerable to disease. Yet another is that vehicle-exhaust fumes react with airborne scent molecules from flowers, making them confusing and unattractive to bees.
But the three most important reasons for the declining number of bees seem to be malnutrition, insecticides and stress. Because these are so important for the future of worldwide honey production, we’ll look at each in detail.
A main cause is shrinkage of wildflower habitats reducing the volume and variety of nectars and pollens. In the UK, for example, wildflower populations have fallen by 95 per cent since the destruction of hedgerows accompanying the need for food production after World War 2. Weedkillers and single-crop farming are also to blame. Worryingly, one in five species of wildflower risks extinction.
The other main cause is the poor nutritional quality of food substitutes such as sugar syrup given to bees if honey stores are low or beekeepers have harvested too much. Malnourished bees are more vulnerable to insecticides, infections and parasites.
A colony needs only 9–14kg/20–30lb of honey to survive the average winter, but can store much more given enough space and successful foraging. In an average year, the average colony in a UK Modified National Hive produces a surplus of 10–14kg/22–30lb. In a good season, a strong colony can produce an extra 18–27kg/40–60lb. And some colonies produce an extra 36–45kg /80–100lb or more. One Australian beekeeper took 285kg/629lb per hive when the flow of eucalyptus nectar was particularly good.
Good beekeepers remove only the honey likely to be surplus to the bees’ needs. Others take as much as possible and give the bees substitute food. The best substitutes contain protein, carbohydrate, fat, vitamins and minerals. But even these are limited in their range and quality of nutrients and other phytochemicals compared with pollen and honey. The poorest substitute, sugar syrup, provides vastly less nourishment.
However, it must be said that if bees can’t make enough honey for their needs, or if honey sets so firmly in the comb that they can’t eat it, substitute food given by beekeepers can save their lives.
At worst, certain insecticides used on farms, gardens, recreational areas, parks, forests, marshes, swamps and hives kill bees outright. Repeated low doses weaken their resistance to infection.
Bees can become stressed by poorly designed hives, overly frequent inspections and lengthy travel when migratory beekeepers take them to pollinate and produce honey from far-away crops.
The way things are going, there will be fewer and fewer bees, less and less honey and a crash in bee-pollinated crop production. But with individual and communal action we can prevent this horrendous scenario.
We can encourage wildflowers by sowing them in gardens, parks, on banks and verges, and around crop-bearing fields. Mowing several times in the first year discourages perennial weeds from taking over. A well-chosen mixture of species can prolong flowering by 6–8 weeks and provide more food for bees.
Farmers can sow bee-friendly wildflowers such as wild carrot that flower after a main crop such as wheat and, as an added bonus, reduce the need for weedkillers. They can also cut hay late to give wild flowers more chance to bloom. State-funded set-aside schemes are good since unploughed farmland encourages wildflowers.
Gardens, parks and other display areas can be planted with bee-friendly flowers. These include alyssum, asters, borage, candytuft, catmint, coreopsis, daffodils, single dahlias, echium, French marigolds, goldenrod, heather, honeysuckle, larkspur, lavender, lemon balm, nasturtium, rosemary, scabious, sea holly, sedum, sunflowers, sweet william, thyme and tobacco plants.
Bee-friendly flowers are preferable to ones that are showy but offer little nectar (such as begonias, busy lizzies, double dahlias and bedding geraniums). Note that bees favour flowers in clumps and sunny places.
Instructions should be followed precisely, with applications timed so levels are low during flowering; open flowers should never be sprayed; and spraying should be done only in the evenings or on dull days when fewer bees are about. Good communication between farmers and beekeepers enables hives to be moved before crops are sprayed.
Insecticidal seed dressings called neonicotinoids are of greatest concern. As a seed develops into a plant, they spread through the whole plant and into its nectar and pollen.
Repeated low-level exposure seems to damage bees’ navigational skills and memory. They may then lose their way to the hive and die. Studies in France, Scotland and the UK have linked neonicotinoids with bee deaths. Researchers at Royal Holloway College in London, for example, studied nearly 1,000 bees from 40 colonies throughout the UK. Each was tagged with a microchip and some were given a cocktail of pesticides mimicking those commonly encountered on crops. After release, those given pesticides were much less likely to return.
However, one major manufacturer says that neonicotinoids are safe for bees and withdrawing them does not improve bee health.
The dilemma for national regulators is that without pesticides we might lose 30 per cent of our crops. But with them, an ongoing decline in bee numbers could give the same result. A great many people would favour bees rather than pesticides. But big business has a lot of clout.
Honey production is under threat in many countries, but we know some of the ways in which we can help. We just need to act.