BBKA module 6: honeybee behaviour. How honeybees use nectar, pollen, propolis and water

purple crocus bee

My friend Suzanne says, ‘I always know that spring is coming when I see my first big fat bumblebee popping out of a yellow daffodil.’ Last week I saw my first honeybee foraging for luminous orange pollen inside a bright purple crocus. Spring is coming.

Following my last post on the behaviour of the foraging honeybee, it made sense to continue studying the collection, storage and use of nectar, pollen, propolis and water by the honeybee colony. So I’ve skipped ahead to 6.9 on the syllabus to bring these sections together.

6.9 The collection of nectar and water and their use by the colony

A honeybee sees a flower very differently to humans. As Alison Benjamin and Brian McCallum describe in A World Without Bees, the two compound eyes on the front of her head are sensitive to ultra violet light ‘expanding the already vibrant colours of the plant world into an explosion of differing hues, and directing the honeybee towards the area of the plant where the nectar and pollen are stored’. The honeybee’s eyes can see lines that guide her to the heart of the flower in a similar way that ‘the lights of an airfield direct planes to the landing strip’. Here’s what happens when she collects nectar for the colony.

nectar collection infographic

6.11 The conversion of nectar to honey including the hydrolysis of sucrose, the evaporation of water and the role of the honeybee in accomplishing these changes

So that’s an overview of how the honeybee collects nectar, processes and stores the nectar as honey, and how the honey is used by the colony. The next flow chart specifically looks at the conversion of nectar to honey.

nectar to honey

Collection and use of water

Honeybees also collect water to bring back to the hive. They tend to collect water from unusual, or what we would consider ‘unclean’, sources such as puddles, drains, bird baths, cow pats and, on occasion, and at the risk of causing annoyance to neighbours, from hanging laundry. The stomach in which water is stored has a valve that microscopically filters and cleans the water that they bring back to the hive.

Water is not stored by the colony so it is collected and used when needed to:

  • dilute honey to be eaten
  • mix with pollen to make brood food (70% water) to feed larvae
  • dissolve hardened granulated sugars
  • cool the hive when temperatures are very high.

6.10 The inter-relationship of nectar, honey and water in the honeybee colony

So this is how nectar and water are brought into the hive and stored and/or used. The simple diagram below brings together their inter-relationship in the honeybee colony.

NECTAR-HONEY-WATER

There is a lot more to learn about nectar, water and honey (as shown on the syllabus for module 3 honeybee products and forage!) but for module 6 I’m focusing on honeybee behaviour.

6.12 The collection, storage and use of pollen by the honeybee colony

Emily and I enjoy watching our bees fly back home with baskets full of brightly coloured pollen. In January and February this is usually a sign that the queen has started to lay eggs again, because the pollen is needed to feed larvae and young bees who need the protein in pollen to develop their bodies. Throughout the year seeing our bees fly home with pollen is usually a good indicator that the colony is ‘queen-right’, meaning that the queen is present and that she is laying, and if our colony has recently re-queened it can be a sign that the new queen has mated successfully and is laying new brood.

p10009021.jpg

And the different colours of pollen packed into the cells in the honeycomb are not only beautiful to look at, but also give us an idea of what flowers our bees like to visit.

Emily and I use a pollen chart throughout the year to identify the pollen of various flowers brought home by our bees. This tells us what is flowering now and what our bees like to eat.

Emily and me keep a pollen chart in the roof of our hive to identify the different-coloured pollen brought home by our bees.

Foragers use a variety of methods to collect pollen from different flowers. Mark L Winston describes this in The Biology of the Honey Bee according to the type of flower:

Open flowers. The worker bites the anthers with her mandibles and uses the forelegs to pull them toward her body.

Tubular flowers. Workers insert the proboscis into the corolla searching for nectar, and pollen is collected incidentally when it adheres to the mouthparts or forelegs.

Closed flowers. The bee forces the petals apart with her forelegs and then gathers pollen on the mouthparts and forelegs.

Spike or catkin flowers. The bee runs along the spikes or catkins, shaking off pollen onto her body hairs.

Presentation flowers. The pollen is collected by workers pressing their abdomens against the inflorescence, causing a pollen mass to be pushed out of the flowers.’

Honeybees can often be seen in flowers their bodies covered with bright yellow or orange pollen grains, which they then ‘dust off’ and brush into baskets on their hind legs.

Here’s another infographic summarising the relationship between bees and pollen.

pollen collection infographic

And finally, propolis…

6.13 The collection and use of propolis by the honeybee colony

Our ladies were too busy sticking propolis on frames to notice we had opened the hive

On a mild day in September 2011, Emily and I visited the apiary while the other beekeepers were away to do some secret beekeeping. We had to work hard with the hive tools to prise open the hive, which was very sticky. When we looked inside our bees were so busy chewing and sticking propolis all over the hive that they completely ignored us!

Propolis, or ‘bee glue’ is a resinous substance collected from sticky buds or tree bark, and seen as shiny blobs on the third legs of foragers flying home. It is most often seen by beekeepers in late summer and in autumn when bees use it to insulate the hive for winter – it makes all the hive parts very sticky and inspections can become difficult.

Here’s why the bees like it though.

pollen collection infographic

My next (and penultimate) revision post before the exam will be written from the point of view of one of our queens and it’s all about swarming and supercedure, something Emily and I know a lot about!

Related links

BBKA module 6 honeybee behaviour: 6.1 the role of the worker bee
BBKA module 6 honeybee behaviour: 6.2 to 6.3 the life of the queen
BBKA module 6 honeybee behaviour: 6.4 a honeybee year
BBKA module 6 honeybee behaviour: 6.5 Social organisation of a honeybee colony and worker policing
BBKA module 6: honeybee behaviour 6.6 The social network including bee dances
BBKA module 6: honeybee behaviour 6.7 the foraging bee

BBKA module 6 honeybee behaviour: 6.5 Social organisation of a honeybee colony and worker policing

Mod 6.5 leadA worker honeybee is patrolling the hive. She walks around the colony watching her sisters clean cells, nurse brood, build comb and fan nectar. She sees drones being pushed aside by returning foragers impatient to unload heavy baskets of pollen. She turns as the queen walks past looking for suitable cells to lay eggs.

Such is the constant activity of the hive that it almost causes her to miss a haphazardly laid egg. Almost. She pauses. The egg lies lopsided along the wall of the cell, not neatly deposited at the bottom. The queen, a precise egg-layer, is never so careless, so the worker climbs in the cell to investigate. Every egg laid by the queen has a signature scent (pheromone) but this egg does not have her mother’s tag – it has been laid by one of her sisters, a rebellious laying worker.

The queen does not need to fear insurrection because her daughters are very efficient at policing themselves. Without hesitation, our worker eats her sister’s egg and if she happens to catch her sister laying more eggs, she will not treat her kindly.

My fourth post for BBKA module 6 honeybee behaviour covers syllabus item 6.5, which discusses the social organisation of the honeybee colony as a well-structured and highly hierarchical community. This time my revision notes are summarised and illustrated by beautiful infographics created for my blog by designer Keith Whitlock.

6.5 The social organisation of the honeybee colony including worker policing.

The honeybee is a eusocial insect, which describes an advanced level of social organisation. The most familiar examples of eusocial insects are bees, ants and wasps, which all belong to the insect order Hymenoptera.

Eusociality is demonstrated by:

  • colony of overlapping generations from eggs and larvae to young and fully mature adults
  • caste system that divides labour between reproductive individuals (queen) and sterile individuals (workers)
  • responsibility for rearing young shared by large numbers of sterile individuals on behalf of the reproductives

The organisation of a honeybee colony revealing a eusocial society is given below:

Mod 6.5 infographic eusociality

Now that’s understood, here’s how the bees get organised inside the hive.

The queen
(diploid, fertile reproductive individual)
The queen is the most important bee in the colony. She lays eggs, providing a constant supply of new bees, and produces queen substance to control the workers and keep the colony working together as a cohesive whole.

Egg layer
The queen fulfils the role of egg-layer thanks to the royal jelly that she is continually fed in copious amounts as a young larva, thus ensuring she has fully developed ovaries and is able to mate. It is only the queen who can lay both fertilised eggs (which become female workers or potential new queens) and unfertilised eggs (which become male drones).

The queen mates not long after hatching and lays around 1,500 eggs per day; she may live between 3–5 years (see revision post 6.2 to 6.3 the life of the queen). She is not only a prolific egg-layer, she is also precise. With her long abdomen, she carefully deposits one egg, placed neatly in the centre, at the bottom of a cell (fertilised with a single sperm or left unfertilised) and marked by a pheromone so that the workers can recognise eggs laid by the queen.

Queen substance
The queen secretes a substance from her mandibular glands called queen substance – a heady mix of chemicals of which the main component is the pheromone 9-oxodec-2-enoic acid (9-ODA). The queen substance is constantly spread throughout the hive as workers lick the queen and then pass the chemicals to other bees. Queen substance, combined with a pheromone given off by her own brood, inhibits the development of the workers’ ovaries – effectively it acts as a natural contraceptive! It is quite effective as normally only 0.01% of workers can produce full-sized eggs and only 0.1% of drones in a hive are the sons of laying workers.

Queen substance modifies worker behaviour in other ways:

  • inhibits building of new queen cells
  • stimulates foraging activities for nectar and pollen
  • encourages workers to build honeycomb

The pheromone 9-ODA is also released by the queen as a scent to attract male drones during her mating flight.

As the queen gets older her queen substance becomes weaker, and her egg-laying decreases, so that she has less control over her workers. They will eventually build queen cells to replace her.

Mod 6.5 infographic queen

Workers and worker policing
(diploid, infertile non-reproductive individual)
If you see a honeybee foraging on a flower in spring and summer she is likely to be a female worker. Almost every bee inside the hive is a worker and female.

Workers are the worker caste and carry out all the tasks for the colony (see revision post 6.1 the role of the worker bee). They live for around 40 days in spring and summer and between 5–6 months over autumn and winter.

Development of infertile females
After hatching, all young larvae are fed royal jelly for three days and then put on a diet of brood food, unless specially selected to become queens. Larvae who are continually fed royal jelly become queens with fully developed ovaries and are able to mate. Worker larvae are not fed royal jelly after day three of their development, have under-developed ovaries and are not able to mate. Their ovaries are unlikely to develop as adult bees due to the pheromones given off by the queen substance and the brood.

Worker policing
However, some workers may produce full-size eggs in their ovaries and become laying workers. Their progeny are destined to become drone because they cannot mate and have no sperm to fertilise their eggs.

Laying workers are quite careless. They may lay more than one egg per cell and because their abdomens are shorter than the queen’s the eggs are often laid haphazardly against the cell wall. They do not differentiate between worker-sized and drone-sized cells, laying drone eggs in worker-sized cells that hatch as drones with stunted growth.

Most importantly, worker-laid eggs are not marked by the queen’s pheromone, which helps other workers to police their illegal egg-laying activities. Worker-laid eggs are usually removed from cells and eaten by other workers (a practice known as oophagy).

Mod 6.5 infographic worker police

Drones
(haploid, fertile reproductive individual)
Drones are the male bees of the colony and it is thought that their only role is to mate with virgin queens (see revision post 6.2 to 6.3 the life of the queen). A drone hatches from an unfertilised egg and inherits one set of chromosomes from his mother, the queen; for this reason, a queen cannot mate with drones from her own colony due to the risks of inbreeding.

Drones that mate with a virgin queen on her mating flight will die in the act, and drones that don’t mate but live to the end of the summer will eventually outlive their usefulness to the colony and be evicted by their sisters.

Drones do no work inside the hive, although beekeepers have observed in spring and summer that colonies with fewer drones can be bad tempered. Perhaps drones fulfil another purpose not yet discovered.

Mod 6.5 infographic drones

I’m looking forward to exploring the next item on the syllabus – dancing bees!

Related links

BBKA examination path and BBKA module 6 honeybee behaviour
BBKA module 6 honeybee behaviour: 6.1 the role of the worker bee
BBKA module 6 honeybee behaviour: 6.2 to 6.3 the life of the queen
BBKA module 6 honeybee behaviour: 6.4 a honeybee year

A great revision post from Emily Heath of Adventures in Beeland: 4th Honeybee behaviour revision post: social organisation of the colony

Mid Buck Beekeepers Association Blog’s excellent revision notes for BBKA module 6

Recommended reading

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