Honey bee colonies under threat from disease and predators

One of the honey bees in a colony kept by Carolyne Liston, chairman of Norfolk Beekeepers Associatio

One of the honey bees in a colony kept by Carolyne Liston, chairman of Norfolk Beekeepers Association. Picture by SIMON FINLAY. - Credit: Archant Norfolk

A national bee health seminar will be held in Norfolk next month to address the raft of diseases and predators threatening East Anglia's hives and colonies.

As summer approaches, the busy hum of honey bees will grow into a chorus of industry in our region's fields and gardens.

But these hard-working foragers are under threat from an increasing array of disease and predators – enough to prompt experts to arrange a national meeting to discuss the protection of hives and colonies.

The Norfolk Beekeepers' Association (NBKA) will hold its Bee Health Seminar at Easton and Otley College on May 23, organised in conjunction with the National Bee Unit (NBU).

Topics under discussion will include European and American foulbrood (EFB and AFB), both notifiable diseases which are highly infectious and deadly to bee colonies.

On the horizon, there's the potential arrival of two predators: The Asian hornet, now established in France, and the small hive beetle, which is present in Italy and could come into the UK via bee imports.

Meanwhile, there is the ongoing challenge of managing varroa, a parasitic mite originating in Asia which attacks the bees' larvae and is now endemic throughout mainland UK.

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Carolyne Liston is chairman of the NBKA, which was founded in 1923 and has about 300 members across the county.

She said EFB and AFB had become a particular concern for beekeepers in Norfolk, with 61 cases of EFB and 57 cases of AFB confirmed by bee health inspectors in 2014.

'Norfolk had the national record for foulbrood last year and they are both very contagious,' she said. 'These diseases spread either through people not checking properly, or not knowing about them.

'Because AFB is so unusual, people don't think to look for it. It has broken out in the past, but the concern is that this AFB has just suddenly appeared in north Norfolk, and we are asking: How did it get here?'

The disease is often inadvertently spread by beekeepers via combs, honey or hive tools being transferred to different apiaries, but it can also be carried by healthy bees robbing honey from an infected hive.

AFB is a spore-forming bacterium which kills the larvae as they grow in honeycomb cells beneath a wax 'capping' deposited by the adult bees.

It can be identified as it leads to sunken caps, which could be probed with a matchstick to see if the larvae had decomposed. If those signs are spotted, the hive must be closed down and reported to a bee inspector. If the disease is confirmed, it will mean compulsory destruction of the colony.

At this time of year, routine inspections involve blowing hessian smoke across the hive to calm the bees, checking that any uncapped larvae are a healthy pearly white colour, and that the colony has fresh stores of nectar and pollen arriving from the workers.

'They need that renewal of cells in the body, and for feeding their larvae,' said Carolyne. 'The colony now is at a critical stage because the winter bees are dying off and the new bees are being born.'

After 12 years of beekeeping, The NBKA chairman described it as a 'fascinating and satisfying' pastime, combining animal husbandry, scientific and craft food interests.

'If it is a reasonable year, I would hope to extract honey in May and at the end of July,' she said. 'But it will depend on what the weather is like and what forage is available to them. I would hope over the course of a year to get at least £50 of honey from a colony.'

The bee health seminar will offer advice from experts including national bee inspector Andy Wattam, and regional bee inspector Keith Morgan. There will be opportunities to look at infected combs and get the latest information on how to recognise and control bee diseases. It is open to anybody who keeps bees, but registration is required.

The seminar will also discuss future threats to East Anglian honey bees which are likely to arrive from continental Europe.

'One is the Asian hornet, which has landed in France in imported pottery from China,' said Carolyne. 'That is likely to come here on the wind.

'It is a very, very aggressive predator. They wait by a hive entrance and grab the foraging bees as they come back into the hive. They can absolutely decimate colonies and we are concerned that it is going to come in on someone's caravan who has been travelling in France.

'Then there is the small hive beetle, which is currently in Italy, and that is a concern for this country as we import Italian bees. If they come here they are another pest that could be quite serious for honey bees. Their larvae eat the brood in the comb and raid the honey stores.

'I think one of the benefits, and one of the disadvantages, of being an island nation is that we feel protected by the Channel and the North Sea, so it is easy to be complacent and not realise how these diseases can be spread.'

For registration forms and more information on the Bee Health Seminar click here.

For more information on beekeeping and bee diseases, click here.

A bee's working career

The sequence of jobs in the ideal bee colony can vary depending on the weather and the requirements of the hive, but the bees generally progress from one job to the next as they age and the relevant glands develop.

House Bees:

1. Cleaning cells – while they wait for their bodies to harden and for their mandibular and hypopharyngeal glands to develop, which produce brood food and royal jelly.

2a. Brood rearing – feeding the larvae before the cells are capped with wax.

2b. Queen tending – feeding and grooming the queen bee.

3a. Receiving and packing nectar and pollen.

3b. Comb building.

Outside bees:

4. Ventilating the hive – standing near the entrance, fanning the wings to produce an air current which evaporates the water from uncapped honey and cools the hive.

5. Guarding.

6 Foraging.

Facts about bees

• There are three types of honey bees in a colony: A single queen, whose job it is to lay eggs, thousands of female workers who do all the work, and hundreds of male drones. It is the females that will be seen in gardens foraging on flowers for nectar or pollen.

• Nectar is turned into honey and stored in the combs as the bees' main source of carbohydrate. Pollen, their source of protein, is mixed with water and fed to the growing larvae.

• Bees have four legs, five eyes and six legs – the rear pair being equipped with stiff hairs to store collected pollen while flying from the flowers to the hive. This collection method for their perfect food may be the origin of the phrase 'the bee's knees', meaning ideal or best.

• Honey bees are believed to fly as far as seven miles for food, however an average distance would be within a mile of the hive. A strong colony flies the equivalent distance to the moon every day.

• Successful foragers will alert the hive to the location of flowers with a rich yield of nectar and pollen by performing a 'waggle dance'.

• Honey bees only sting to protect the colony or when frightened. Only female workers and the queen can sting, and they will die in the process.

• Small colonies can start with about 8,000 bees, but larger ones could hold between 60-100,000 at the height of the summer.

• Queens start laying in January and can lay up to 2,000 eggs a day throughout the summer. The eggs hatch into larvae, which is fed by the adult bees.

• When the larvae are nine days old, adult bees seal the opening of each cell with a cap of wax. The larvae grows into an adult bee inside the sealed cell, completing its metamorphosis. It is then born into the colony.

• Summer bees live for about 40 days and spend half of that time foraging.

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