Latest published research on pesticides and damage to bees.

Read the open-access, full-text article here:
http://dx.plos.org/10.1371/journal.pone.0014720

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Sub-Lethal Effects of Pesticide Residues in Brood Comb on Worker Honey Bee (Apis mellifera) Development and Longevity

Abstract: Background
Numerous surveys reveal high levels of pesticide residue contamination in honey bee comb. We conducted studies to examine possible direct and indirect effects of pesticide exposure from contaminated brood comb on developing worker bees and adult worker lifespan.

Methodology/Principal Findings
Worker bees were reared in brood comb containing high levels of known pesticide residues (treatment) or in relatively uncontaminated brood comb (control). Delayed development was observed in bees reared in treatment combs containing high levels of pesticides particularly in the early stages (day 4 and 8) of worker bee development. Adult longevity was reduced by 4 days in bees exposed to pesticide residues in contaminated brood comb during development. Pesticide residue migration from comb containing high pesticide residues caused contamination of control comb after multiple brood cycles and provided insight on how quickly residues move through wax. Higher brood mortality and delayed adult emergence occurred after multiple brood cycles in contaminated control combs. In contrast, survivability increased in bees reared in treatment comb after multiple brood cycles when pesticide residues had been reduced in treatment combs due to residue migration into uncontaminated control combs, supporting comb replacement efforts. Chemical analysis after the experiment confirmed the migration of pesticide residues from treatment combs into previously uncontaminated control comb.

Conclusions/Significance
This study is the first to demonstrate sub-lethal effects on worker honey bees from pesticide residue exposure from contaminated brood comb. Sub-lethal effects, including delayed larval development and adult emergence or shortened adult longevity, can have indirect effects on the colony such as premature shifts in hive roles and foraging activity. In addition, longer development time for bees may provide a reproductive advantage for parasitic Varroa destructor mites. The impact of delayed development in bees on Varroa mite fecundity should be examined further.

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Sharilyn Stalling, the brains behind BeeAndGarden.com, has made another great video about the loss of our bees. This video is full of food for thought. Please watch the video in it's entirety, and if you haven't seen the first video, be sure to view it at http://www.youtube.com/watch?v=CeOxzzm6sZs

Wales honey bees decline 39 per cent
21/1/2010
The plight of the honey bee has been highlighted by Pembrokeshire County Council.

Honey bee populations in Britain have declined at an alarming rate over the past decade with a 39% decline in Welsh bee colonies in 2009.

This week the Council's environment and overview scrutiny committee heard presentations about the situation from two leading bee experts.

John Verran, Regional Bee Inspector for Wales and John Dudman, Secretary of the Pembrokeshire Beekeepers Association told members about the drastic decline in honey bee colonies, the causes and what authorities and bee keepers were trying to do about it.

The meeting was attended by many local members of the Women's Institute, which has made the plight of the honey bee one of its national causes.

Chairman of the Committee, Councillor Peter Stock said he was very concerned to hear about the decline.

"This is a very important issue and something which I believe as a Council we should take up," he said.

"The Environment Overview and Scrutiny Committeee has put this matter into its work programme and potential further scrutiny can now take place.

"This meeting is a start but I think - working with others - we should play our part in trying to ensure the success of honey bee populations in the future."

Earlier the meeting heard John Dudman explain how although bee colonies traditionally declined by around 5% to 10% a year, they had fallen by 34% in Wales 2008 and by 39% last year. Populations in England had declined by similar amounts.

He said although there was no obvious cause, one major factor was believed to be an increase in the incidence of varroa mite infestations in hives and there were also concern about the effects of pesticide spraying on crops and in gardens.

He said DEFRA and the Welsh Assembly Government had last year published a plan to improve the health of honey bees, while an additional £4.3m was being spent by the Government to gather more information and undertake more research into pollinating inspects.

"At a more local level we as an association are providing training courses for beginners and also setting up more local beekeeping groups," he said.

"Bee keepers need education and they need to be given information. The education and training of bee keepers is essential."

Source: Oldham Chronicle, UK
Reporter: Janice Barker
Date online: 23/07/2009
Oldham Euro-MP Chris Davies has a bee in his bonnet about the endangered insects.

He used his first question of the new term at the European Parliament to highlight the alarming decline of British bees.

In the last two years bee numbers have dropped by around 30 per cent and the Government recently announced funding of around £2 million to study the decline.

Liberal Democrat Mr Davies wants the European Commission to consider banning insecticides called neonicotinoids, used to protect plants from insects. Its use has been linked to bees dying, and led to severe restrictions in France and Germany. Mr Davies said: “The Commission needs to consider a ban on these chemicals before the bee decline starts showing up in food shortages.

“Better to take action now as a precaution than risk the destruction of bee colonies because we left it too late.

“Protecting the environment isn’t just about the big visible changes like the melting ice in Greenland or the pollution in our atmosphere, it’s also about protecting the tiny creatures who keep our plants growing and our world running.”

Bees are believed to contribute £120 million per year in direct economic benefits to Britain by pollinating commercial crops.

About a third of food comes from plants pollinated by them. Scientists are trying to discover the reasons why bees have been disappearing in large numbers. Many studies focus on the varroa mite parasite that weakens colonies by feeding on bees.

Neonicotinoids are less studied despite evidence from Germany and France in particular that they can cause bee colony numbers to collapse.

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SOURCE: Friday, 9 August, 2002, 13:25 GMT 14:25 UK   BBC News

Fungi help combat honeybee killer

Varroa Mite
Varroa Mite
Varroa mites have devastated some honeybee colonies

Fungi could soon be helping beekeepers control a parasitic mite that before now has killed up to 70% of colonies.Research shows that the fungi can kill Varroajust as effectively as the chemicals currently used to keep populations of the parasite manageable.

The fungi could prove key to protecting hives as the mites become resistant to chemical controls currently used to treat them.

But it could be some years before beekeepers can buy the fungal controls off the shelf for use in hives.

Killer parasite

The Varroa destructor mite was first found in the UK in 1992 and has wrought havoc on feral and hive populations.

    

 Chemicals are very efficient and cheap but the downside is that their use is not sustainable in the long term
David Chandler, HRI Association

 

Some beekeepers lost almost 75% of their colonies to the mite that preys on young bees weakening them, and making them susceptible to other infections.

Pesticides have helped keep the mites populations at low levels but some fear that colonies are about to undergo another wave of devastation as mites become resistant to the pyrethroids used to kill them.

Overuse of the chemicals has produced populations of resistant mites in hives in the South West of England and the resilient strain is expected to spread across the country.

But research carried out by Dr David Chandler and Dr Gill Davidson at the Horticulture Research International Association in Warwickshire has found that insect-killing fungi could take over the job of controlling the mites.

"Fungal controls have a long history since Pasteur," said Dr Chandler, "but interest is increasing because of public concern over the environmental impact of pesticide residues in food."

Good bugs

By contrast with chemical pesticides the fungi tested by the scientists are found in nature, are harmless to mammals, including humans, and leave no residue to accumulate in food.

    

Bee Larva with mites
Bee Larva with mites
Varroa attacks bees at all stages of their life

 

Testing by the researchers has identified more than 40 types of fungi from six species that are capable of killing theVarroa mites within 100 hours.

"Using living organisms to control other living organisms is a different form of pest control," said Dr Chandler. "Chemicals are very efficient and cheap but the downside is that their use is not sustainable in the long term."

Although the fungi occur naturally the mites rarely encountered them inside hives because honeybees kept their homes so clean, he said.

The promising fungal types are now being tested to ensure they are as effective in the high temperatures and humidity levels found in bee hives.

Dr Chandler said the aim was not to eliminate the Varroa mite, but to ensure that populations were kept to very low levels.

    

Dead Varroa Mite
Dead Varroa Mite
Fungi overwhelm Varroa mites

 

The fact that the fungal controls killsVarroa by different methods could mean that the mites never develop the kind of resistance that is making pesticides less effective.

The fungi spores kill the mites over a week long period by penetrating their cuticle and poisoning the bug, drying it out and damaging its cells and organs.

The two researchers are now embarking on a three-year project with the IACR-Bee Research Unit in Rothamstead to identify the best strains of fungi and find the best way to distribute them around a hive.

Dr Chandler said that honey bees were already used to spread fungi on some commercial crops so it might prove easy to adapt these methods to spread the anti-Varroafungi inside hives.

One idea is to use a fungi footbath that bees have to walk through when entering the hive to help them spread the spores around when they deliver nectar and pollen.