Report of April 2019 meeting

Dance Like No-one’s Watching – The role of honeybee communication in colony well being

A talk by Lynne Ingrams

Lynne, who is a Master Beekeeper, explored the Why? and How? of the many different forms of communication between bees, how they respond to their environment, and how this affects the ability of the colony to survive and thrive.

The honeybee colony is often referred to as a super-organism, which means an organism consisting of many individual organisms. The term describes a social unit of animals such as honey bees, bumble bees and ants, which have highly organized division of labour, and where individuals are not able to survive by themselves for any length of time.

Why do bees need to communicate?

There may be 60-70,000 bees in a small enclosed space, so there is a need to operate efficiently. There is also a need to respond swiftly to changing threats and opportunities. Ideally, actions need to be coordinated.

Information flow within the bee

The two main systems for communication within the bee are the nervous system and the endocrine system. The nervous system works very quickly with electrical messages passing to and from the brain to other parts of the bee. The endocrine system produces hormones, which are chemical messages. These are produced in cells or glands in one part of the body and affect cells in other parts of the organism. Thus they may be slower to act compared to nerve impulses.

Information flow within the colony

Because of bees’ mobility they can use dance language, trophalaxis and messenger bees to convey information. Bees also produce pheromones that act on other bees through the hive atmosphere (see below). An example would be the sting pheromone which can produce a rapid response.

Division of labour

Queens and drones each have their own jobs in the colony. Workers, however, progress through a series of physiological changes to their bodies as they grow older, enabling them to sequentially act as nest cleaners, larval feeders, queen feeders, honey and nectar processors, wax makers, guards and lastly, foragers. This provides flexibility and a rapid response to changing situations.

How do bees respond to changes around them?

The colony relies on indirect stimulae of the shared environment and will respond accordingly. Thus if the temperature rises to a dangerous level more bees will be recruited to forage for water. Cold weather will produce a clustering response to protect the brood.

Lynne talked about the ‘technologies’ available to the bees within the superorganism. Thus scout bees recruiting house bees to a good nectar-producing flower will use dances, trophalaxis, antennation, vibration and scent. During swarming they will use pheromones, dances, vibration and piping.

Pheromones

Probably the best known is the scent of the queen which promotes colony cohesion. Workers produce Nasanov pheromone, the ‘come hither’ signal, and the alarm pheromone meaning ‘come and help’. Drones produce their own pheromone used in DCAs and worker brood pheromone inhibits development of worker ovaries as well as stimulating pollen collection.

Food Regulation

Collection of nectar, pollen and water needs to be an efficient, coordinated operation with appropriate division of labour between foragers and storers/receivers. Nectar, for example, is supply driven. Ease of unloading back at the hive dictates what happens next. Too long (50 sec+), and the forager will do a tremble dance to recruit more receivers. A very quick response (less than 20 sec) and the forager will perform a waggle dance to recruit more foragers. An intermediate response time will produce a return to foraging.

There is also a stop signal used to decrease recruitment of foragers when it takes too long to unload. The returning bee will head butt waggle dancers and ‘pipe’, causing them to ‘freeze’. Watch out for this behaviour in your hives!

Another interesting behaviour you might see is the dorso-ventral abdominal vibration or DVAV. This signal is used to recruit non-foragers to forage when there is a long period of flow or a new flow after a dearth. New recruits either go to the dance floor to watch waggle dancers or fly direct to the forage if previously visited.

Pollen regulation within the colony is demand driven. Nurse bees consume pollen and produce protein rich food for foragers. A plentiful supply of high protein quality will tend to inhibit pollen collection whereas fewer feeds or lower protein quality will tend to stimulate pollen collection.

Water regulation is also demand driven, for example when temperatures are high. The response is to recruit unemployed foragers to increase water collection without affecting nectar collection.

Communication within swarming

On the day of the swarm the workers are prompted by a piping signal to warm their wing muscles in the last hour before setting off. Just before setting off, the colony is activated into flight by a few bees performing buzzing runs in the hive. The swarm then settles into a cluster nearby to check they still have the queen, detectable by her pheromones. Nest site selection is arrived at by competing waggle dancers and when consensus is reached the colony lifts off with more piping signals and the scout bees guide the mass by buzzing runs through the moving swarm to the new nest. Finally, bees will be seen at the entrance fanning Nasanov pheromone to guide the stragglers in.

There are many more ways in which bees communicate and probably just as many that we have yet to learn about!

Lynne gave two references:
The Super-organism – Bert Hölldobler & E.O.Wilson
The Wisdom of the Hive – Tom Seeley

Report of March meeting 2019 – A talk by Brigit Strawbridge

Bees: Importance of diversity and relationships with flowering plants

Brigit began by saying she intended covering ALL bees, not just honey bees, as well as other pollinators, in order to show the importance of diversity in plant ↔ bee relationships.

To put things in perspective there are roughly:

320,000 flowering plant species worldwide,

more than 300,000 pollinating animal species

and 25,000 bee species.

In the UK our pollinators include:

59 butterfly species,

2,500 moths,

7,000 flies,

9,000 wasps,

4,000 beetles and

270 species of bees.

‘Indicator Species’

The importance of bees became apparent when Brigit explained that about a third of our food and beverage producing plants are pollinated by bees and that up to 80% of flowering plants are dependent on bees for reproduction. No wonder that bees are regarded as a key ‘indicator species’. The knock on effect of anything affecting bees will soon be felt in the rest of the environment.

What is a bee?

From Brigit’s photos we learned that bees range in size from Wallace’s giant bee (Megachile pluto), about 38mm long, to a tiny solitary bee the size of a midge! Worker bumble bees in the UK can be up to 24mm.

Briefly, the life cycle of a bumble bee starts with the emergence of the fertilised queen in the spring. She feeds on nectar and starts building a nest. She provides pollen and nectar for the developing young workers who will take over the duties of colony maintenance, leaving the queen free to concentrate on egg laying. Later in the year the queen lays drone eggs instead of worker eggs, followed by fertile female eggs. The males leave the nest and move to other areas while the queens mate and find a crevice to hibernate over winter.

Bee decline

Causes of bee decline in recent years can be largely attributed to habitat loss and pesticides. Further damage is being caused by climate change, invasion by non-native species and pollution. All of these effects reduce biodiversity and the ability of ecosystems to survive and thrive.

Cross pollination

Cross pollination is the key to diversity of the flowering plants which have been evolving alongside the insect world for the last few tens of millions of years. So we see a range of characteristics in bees enabling them to take advantage of the numerous niches in the plant world. UK bumble bees, for example, have a proboscis length of 15-20mm whereas the honey bee proboscis is only 6mm.

Pollen collection methods vary between species. We are familiar with the pollen baskets of honey bees but red mason bees will ‘buzz’ on a flower to dislodge pollen, which sticks to the hairs on its abdomen, called the scopa. Sometimes, if the proboscis is not long enough, buff tailed bumble bees will cut a hole in the corolla to reach nectar and pollen, a process called larceny.

Biodiversity facts

98% of wild flower meadows have disappeared in the last century.

Neonicotinoids persist in the environment and pass into the soil and water courses. From here they are reabsorbed into plants, pass into nectar and pollen, and end up affecting pollinators. The toxic mix of pesticides and fungicides affects the ability of bees to ferment bee bread which is essential to their existence.

What can we do?

• Don’t tidy your garden too much. Leave heaps of ‘rubbish’ for bees to nest in.
• Make or buy ‘Bee Hotels’. Keep them clean.
• Plant for a succession of flowering plants all through the year. Brigit’s list plus a few extras – mahonia, crocus, aconite, celandine, snowdrops, hellebores, dandelion, flowering currant, pulmonaria, vipers bugloss, nepeta, borage, wild marjoram, Michaelmas daisies, sedum, ivy, heathers.
  Don’t forget the trees and shrubs – viburnum , mimosa, camellias, sarcococca, skimmia.
• Plant wild flower seed mixes for meadows if you have room.

Recommended reference books:

Field Guide to the Bees of Great Britain and Ireland – Steven Falk

Plants for Bees – Kirk and Howes (available to East Devon members from the branch library)

* All images © Brigit Strawbridge