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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’

Ashy mining bee
Ashy mining bee, Andrena cineraria *

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

Pollen on the scopa
Pollen on the scopa *
Pollen baskets
Pollen baskets *

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 scope. 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.
Male white tailed bumble bee
Male white tailed bumble bee – with moustache *

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


Report of February meeting 2019

Chronic Bee Paralysis Virus (CBPV) – A talk by Clare Densley, Manager of Buckfast Abbey Apiaries

What is CBPV?
CBPV mainly attacks adult bees and causes two forms of ‘‘paralysis’’ symptoms. The most common form is characterised by an abnormal trembling of the body and wings, an inability to fly leading to crawling on the ground, bloated abdomens, and dislocated wings. The other form is identified by the presence of hairless, shiny black bees that are attacked and rejected by guard bees at the entrance to the colony. Both forms of symptoms can be seen in bees from the same colony.

Diagnosis of CBPV

Bees infected with CBPV
Bees infected with CBPV *

The virus multiplies to millions within the bee affecting most organs with little chance of the individual bee surviving. In addition to the signs above you may find, on the top bars, slow, slightly shaky bees which do not react to smoke.
Check all the symptoms before deciding the cause of dead bees inside and/or outside the hive. Do not assume that many dead bees means pesticide poisoning. CBPV is, as its name suggests, a chronic problem. Not all bees will die at once, stress can accelerate the spread of infection or improving conditions can cause it to clear up.

In Clare’s experience queens often seems to remain unaffected and can carry on laying as long as they are well fed. This has also been noted by Giles Budge. Advice from older books and the NBU suggest re-queening with a queen from a less susceptible strain of bee. Clare found that re-queening made no difference to a colony which was suffering badly. Also removing a queen from an infected colony and introducing her to a healthy colony did not cause disease to develop.

What is a virus?

Hairless, shiny bees
Hairless, shiny bees *

A virus is a small infectious agent that replicates only inside the living cells of other organisms. Viruses are basically parasites. They invade an organism, take over their cells and turn them into factories for producing more viruses. There are 23+ viruses that affect honey bees. Viruses normally range from 30 to 100 nanometres (1 nanometre = 1 millionth of a millimetre).

How does CBPV infect bees?
Infection often initiates when the colony is stressed (overcrowding, nutritional stress, but not via varroa infestation). Usually passed from bee to bee with a few virus particles entering the cuticle where hairs are broken off. By comparison, transmission by feeding requires hundreds of virus particles.

CBPV can also infect some ant species which act as a reservoir in the wild.

Drifting has been implicated in spreading the disease between colonies.

How does the virus act?
Infected bees contain millions of viral particles, half of which concentrate in the head causing the symptoms associated with the nervous system. Many more accumulate in the hind gut adding to viral load inside the hive.

‘Good’ gut bacteria are important in bee health, helping to fight pathogens by blocking entry into bee cells. Good nutrition is therefore essential for fighting the disease.

Treating CBPV

Bee with the virus
Bee with the virus *

The NBU recommends that in strong colonies showing signs of CBPV, beekeepers ensure there is plenty of room by adding supers or an extra brood box and also that colonies are well fed.

Clare doses the bees with Varromed (formally Hive Clean) right from the outset. This seems to activate not only the grooming process but also seems to encourage the bees to clear out their dead.

Infected colonies may be short of readily available food due to a lack of foragers and will benefit from feeding direct to the comb in the brood area. Spray or pour liquid feed onto an empty brood frame and put it next to brood. Dribble syrup onto the bees as well. These methods work better than feeders.

Clare uses garlic powder and probiotic capsule powder added to the syrup which prompts an immediate feeding response. See below for Clare’s recipes for a Fondant Recipe for Bees and a Garlic Syrup for Bees

Clean up dead bees inside and outside the hive.

Don’t overcrowd your apiaries. If hives are badly infected, set up a new apiary and move the affected hives.

Practice good apiary hygiene.

A mixture of normal and affected bees

* Images courtesy of The Animal and Plant Health Agency (APHA), Crown Copyright

Clare’s Fondant Recipe for Bees
Icing sugar- 1kg
Water- 100 ml
Garlic powder (optional)- 1tsp
Honey or invert sugar (ambrosia)- a dashMethod
Empty the icing sugar into a clean washing up bowl and add the garlic powder and honey or ambrosia.
Add the water and mix with your hands until you are able to knead the mixture like dough.
Put into a greaseproof wrapping or a plastic bag so that it doesn’t dry out.
Place over the feed hole on the crown board of the hive.
Clare’s Garlic Syrup for BeesMethod
Make up 2:1 sugar syrup (or use Ambrosia)
2 heaped teaspoons of pure garlic powder (not garlic salt) should be placed in a large mixing jug.
Add a tiny bit of syrup so that you can mix it to a paste (as you would cocoa or custard powder).
Then dilute this mixture with a little more syrup.
Stir thoroughly so that it all amalgamates.
Do this again.
Continue this process until the mixture is liquid enough to pour freely.
When you get to this point you can add more syrup until you have 5 litres in all.
Mix thoroughly and pour the solution into bottles or a canister.

With thanks to Clare Densley for sharing her recipes for use in combating CBPV.

News & Events

What’s that Buzz? Plants hear when bees are coming
New research has shown that plants can ‘hear’ sounds around them and flowers respond to the buzz of approaching bees by producing sweeter nectar. The research biologists from Tel Aviv University played recordings of flying bee sounds to evening primrose flowers and found that after a few minutes the sugar concentration in the flower’s nectar had increased by 20% on average when compared with flowers left in silence or submitted to higher pitched sounds.
The authors of the report say that, for the first time, they have shown plants can rapidly respond to pollinator sounds in an ecologically relevant way.
Producing sweeter nectar in response to the sounds of bees can help entice the insects to visit the flowers and increase the chances of its pollen being distributed.
Thanks to Ann P. for spotting this article in the Times.
Scientists sew trackers to Asian Hornets to find and destroy nests before they kill honeybees
Britain’s beekeepers are turning to technology to prevent aggressive Asian hornets destroying their colonies. In a first successful trial, experts at the University of Exeter attached tracking devices to the backs of the voracious hornets and then followed them back to their nests.
Asian hornet information
The June edition of the BBKA News has extensive information about the Asian hornet threat. In particular, pages 209 and 210 have full colour reproductions of the Asian hornet alert document issued by the Non Native Species Secretariat (NNSS) for you to cut out and use as your personal guide to identification of this invasive species.
EU agrees total ban on bee-harming pesticides
More information can be found at:          https://www.theguardian.com/environment/2018/apr/27/eu-agrees-total-ban-on-bee-harming-pesticides?CMP=Share_iOSApp_Other