Neonicotinoid pesticides and bees

The second speaker at our annual Cornwall Beekeepers Association/West Cornwall Beekeepers Association ‘Bit of a Do’ conference in September was Dr Ben Woodcock, from the Centre for Ecology and Hydrology (CEH), on ‘Neonicotinoid pesticides and bees’. 

Ben is an Ecological Entomologist in the Community Ecology Group at CEH. He has a confident, loud, and extremely fast speaking style which forces you to sit up and pay attention! I had to really concentrate in the warm lecture theatre to take it all in, as though he explained his research in simple terms it’s still quite a technical subject.

He began his talk with a bit of background on how bees are doing in the UK, and why neonics may have contributed to the decline of some species. At the moment honey bees can only deliver about 34% of pollination demand in the UK, so farmers do need wild solitary and bumble bees for pollination too. There are a few species which have done really well under modern agriculture – for example, the Ashy mining bee. But there are plenty of others doing really badly.

The issue with neonicotinoid pesticides (neonics) is that they stay inside the pollen and nectar of treated plants over a long period of time (but at a low concentration). Typically test studies into the toxicity of neonics are just short-term studies carried out over about ten days, whereas in real life neonics affect honey bee colonies over periods of months.

Ben mainly discussed two studies he’s worked on which investigated the effect of neonics on bees. The first was:

Impacts of neonicotinoid use on long-term population changes in wild bees in England (Nature Communications, 2016; 7: 12459.)

Ben and his fellow researchers divided 62 species of wild bees into two groups:

  • 34 known to forage on oilseed rape (OSR)
  • 28 not known to forage on OSR.

The study found that wild bee species which forage on OSR were 3x more negatively affected by neonics than non-foragers. Ben stressed that neonics are just one factor affecting bees. However, the research indicates that they add detrimental extra pressure on wild bee species.

Bumble on blackberry bramble


The second study Ben mentioned was one he worked on, a big pan-European study across three countries, the UK, Hungary and Germany:

Country-specific effects of neonicotinoid pesticides on honey bees and wild bees (Science 30 Jun 2017: Vol. 356, Issue 6345, pp. 1393-1395)

He acknowledged that the funding for this was controversial, as the pesticide giants Bayer and Syngenta contributed £3m towards it. To ensure that the research remained impartial, the results were peer-reviewed and all emails associated with the research were recorded.

In the study 36 farms across the three countries were each allocated to a treatment: no neonics (control), Modesto (Clothianidin) or Cruiser (Thiamethoxam) – Modesto and Cruiser are big neonic products. There was an average of 60 hectares of sown OSR surrounding the farms. Six honey bee hives, twelve buff-tailed bumble colonies and a number of red-mason bee nests were put at each site. The study looked at the resulting overwintering success, colony strength and forager mortality of the bees.

With the honey bee hives, the honey bees exposed to Clothianidin in Hungary and the UK suffered higher mortality over the following winter. The neonics appeared to have less of an effect on the German honey bees. Ben said this may be because the bees relied more on OSR in the UK and Hungary, plus the OSR happened to flower later at the German sites, so the German bees had a more varied diet. At the beginning of the study the German honey bee bee hives were also less diseased, with lower varroa levels. Whereas the UK hives sourced for the study happened to be quite small and diseased – hives in a poor environment with a lower variety of forage crops are more vulnerable to disease to begin with.

For the wild mason and bumble bees, the higher the concentration of neonics found in their nests, the more their reproductive potential (measured in new queen or egg cell numbers) declined.

Ben then went on to talk about neonic residues in honey, which he studied in Woodcock et al (2018)  ‘Neonicotinoid residues in UK honey despite European Union moratorium‘. Neonic residues were identified in the honey samples, even for honey harvested after the moratorium in 2014. However, the concentrations were typically low and the likelihood of honey containing neonicotinoid residues was higher before the moratorium than after it. There’s a National Honey Monitoring Scheme run by CEH which UK beekeepers can get involved with – donate honey and they do analysis on it to identify the mix of pollens collected by the bees. The samples are also being archived for research in the future. If you’re into Twitter you can follow the scheme at @CEH Honey.

Following the neonics ban, farmers haven’t all switched to organic methods and stopped treating their oil seed rape. Instead, they’re using pyrethroid insecticides more – but some of the main species of aphids and beetles that feed on OSR have developed pyrethroid resistance. As a result, Ben suggested that OSR may stop being an economically viable crop in some parts of the UK. Unfortunately there is no obvious big alternative crop which is bee friendly. Soya is likely to expand in the UK, but it doesn’t require insect pollination. In the future, will oil seed rape honey no longer clog up the supers of beekeepers here?

Honey bee on borage. Courtesy The Food and Environment Research Agency (Fera), Crown Copyright.




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Maximising your honey crop – tips from Tony Harris

At the weekend I heard Tony Harris, a Scottish bee farmer, give two talks at the annual Cornwall Beekeepers Association/West Cornwall Beekeepers Association ‘Bit of a Do’ conference. Here are my notes from his talk, which had plenty of jokes along with plenty of great tips.

Obviously Scotland is a looong way up from Cornwall, so Tony reckons his hives in the Moray Firth are about two months behind ours. After going up to 150 hives last summer and nearly killing himself running around after them all, this summer he’s reduced his operations down to 70 hives. He needs honey for money, so here’s his advice on how to get it.

  1. You need a plan – write it down
  2. You need the right bees – young queen, strong colony. More than 1 queen per hive helps!
  3. Rigorous management – regular inspections
  4. Swarm prevention and control (more on that later)
  5. Apiary location – know your forage! And think about the numbers of hives, not just in your apiary but locally.

Some general tips

  • Keep strong colonies – build up large colonies before the main summer flow
  • Check stores in winter
  • Replace 1/3 of your brood combs per year – consider the ‘shook swarm’ method to do all your brood combs in one go in spring
  • Cull poor queens
  • Carry out integrated pest management for varroa all season, monitor!
  • After you’ve dealt with swarming and have seen the new queen is laying, relax inspections. Let them get on with it.
  • Build up a store of drawn comb for supers. You can keep using super comb for years and years.
  • Tony doesn’t mark his queens the year they emerge, as he’s had them balled by the bees if he marks too early. Instead he waits for the following spring – easier then too, as there’s less bees in the colony come spring.

Tips for finding queen

  • Use minimal smoke
  • Do not be distracted, have a one-track mind on finding her
  • Go straight to the middle brood frames and examine the ‘dark side’ of frames first as you lift them out.
  • Last resort – use the wine method! (This would be when you phone up your best beekeeping buddy and offer them a bottle in return for them finding her majesty).

Getting foundation drawn

  • Tony does a lot of ‘chimneying’. This involves putting an empty large poly brood box full of foundation over a colony in a poly nucleus, and feeding. He will quickly have a box full of drawn out foundation.
Brood frame containing honey

Mmmm honey

Tony’s main honey crops

  • Oilseed rape (OSR) – harvest May/June
  • Main summer – harvest August
  • Ling heather – harvest September

He takes colonies to OSR in mid-April, puts three supers on at once, then goes on holiday for a week. Then comes the hard part – “If you’ve got a nice job you enjoy don’t even think about being a bee farmer”. After returning from holiday he extracts the oil seed rape honey fast, as otherwise it sets like rock extremely quickly. He will extract 10 supers a day, in 16 hour shifts. Starting in the early morning, working through to 10pm at night, having a shower, then starting again the next morning. Hot, heavy, sweaty work.

Part of the skill of being a bee farmer is keeping strong colonies, which means avoiding having swarms. Tony uses a much more proactive form of swarm control than me, which I was intrigued by. He’s found that making up nucleuses is the easiest method for him. He removes 1,2,3 or 4 frames from a colony in spring to delay its swarm preparations. He then puts foundation in the middle of the boxes the frames are taken from – as he noted, contrary to what beekeeping books will tell you!

The removed frames are used to make up 5-frame nucs: 2 frames of honey/pollen, at both ends, 2 frames of eggs/larvae, 1 frame foundation, plus bees shaken in. So instead of waiting for queen cells like I do, he effectively forces the bees into an early swarm, making their new queens in the nuc instead. I’m interested in trying this out, as what with work, a young family and having my bees at an out-apiary, it can be challenging keeping up with all the swarms down here!

My next blog post will be notes from Dr Ben Woodcock’s talk on “Neonicotinoid pesticides and bees”.

Frame of honey

A frame of honey, back in London a few years ago.

Posted in Colony management, Events, Honey, Swarms | 19 Comments

August bee update

My beekeeping activity is winding down now for the year. The threat of swarms has passed and my focus is now on getting them ready for winter. My Nessa hive seemed to lose Queen Nessa sometime in July, so I combined them with Queen Kensa’s hive using the traditional newspaper trick. Thankfully the resulting multi-storey hive didn’t break Drew’s home-made hive stand.

Meanwhile, my poly nuc colony (which I have named Demelza to continue my Cornish names theme), have been moved into a full-size poly hive. My reason for choosing a poly hive was a combination of economics and practicality: 1.) they’re a lot cheaper 2.) no hammering is required to put them together. They just need a coat of paint – I don’t know how I missed that corner! The downside is that you can’t sterilise them with a good blowtorching.

Demelza poly hive

Demelza poly hive

I’ve taken a small amount of honey from Kensa (3 frames), the rest is being left for the bees. As I don’t want to buy an extractor, and borrowing one through my local association feels like extra work, I’m going for a crush-and-strain method. I’m using muslin as a filter, supported by a colander steamer, so we’ll see how well that works.

The first step of my winter prep is treating against varroa mites, I like to do this in late August/early September. My usual autumn treatment is Apiguard, which is nice and easy. This year I’ve been trying out Api Life Var, as our local bee inspector recommends alternating thymol treatments each year. So far I’m not getting on that well with it, the wafers are so crumbly and have to be changed each week. I’ve also just read that Api Life Var shouldn’t be used with poly hives as it can melt them… oops.

Below is a little gallery of some of the flowers out in the late Cornish summer. Sedums, michaelmas daisies, sweetpeas and herbs like mint and oregano are in bloom. Just this week I’ve heard the modest pale-green flowers of ivy surrounded by buzzing. Blackberry is long over; it’s now time to pick the berries and apples in the garden. It’s officially apple crumble season – a very satisfying time of year. What’s flowering where you are?

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US and UK honey bee colony survival rates

I saw some new data come out recently on US and UK overwintering rates so thought I would take a look at it. It’s probably impossible to compare the two countries though, because the climate, diseases and scale of commercial beekeeping are so different. In the UK most beekeepers are hobbyists and colony collapse disorder isn’t even officially recognised as a problem. But beekeepers in both regions do share a common no.1 enemy – varroa.

Based on the data, it sounds like honey bees aren’t doing too badly – probably the bees we really need to worry about are the ones that we’re not counting, the bumbles and tiny solitary bees that go unnoticed by most people.

US survival rates

The United States Department of Agriculture (USDA)’s National Agricultural Statistics Service (NASS) began collecting data on honey bee health and pollination costs in 2016, “to build an even more robust scientific body of knowledge on honey bees“.  Sadly the data collection had barely begun before the USDA announced this year that it’s being suspended.

Still, you can see the reports for 2016-2019 at Honey Bee Colonies releases. Perhaps one day the value of science and data will be appreciated again and the surveys will continue to be collected once more. The 2019 survey data, published 1st August 2019, tells us that:

  • Honey bee colonies for operations with five or more colonies in the United States on January 1, 2019 totaled 2.67 million colonies, up 1% from January 1, 2018.
  • Honey bee colonies lost for operations with five or more colonies from January through March 2019, was 408 thousand colonies, or 15%.
  • During the quarter of October through December 2018, colonies lost totaled 445 thousand colonies, or 16%, the highest number lost of any quarter in 2018.
  • Honey bee colonies lost with Colony Collapse Disorder symptoms on operations with five or more colonies was 59.9 thousand colonies from January through March 2019. This is a 26% decrease from the same quarter of 2018.

  • For an interesting perspective on the USDA cancelling the honey bee tracking survey, and easy tips on what you personally can do to help bees, see ‘USDA discontinues honey bee tracking‘ by the husband & wife blogging team Married with bees.

Survival rates for England, Scotland, Wales, Channel Isles, Isle of Man and Northern Ireland

The British Beekeepers Association (BBKA) have released data for the winter of 2018-19 in their monthly magazine and a June 2019 press release, ‘Record low level of winter losses of honeybees‘. The data comes from a voluntary online survey completed by 5581 members.

The BBKA says:

“The overall winter survival rate was 91.5% or 8.5% losses. In England the rate was 91% survival with 9% losses, in Scotland 79% survival with 21% losses, Wales 94.3% survival with 5.7% losses and in the Channel Isles, Isle of Man and Northern Ireland survival rates were all above 98% so losses of less than 2% in those places.”

We’re doing well! As we’re quite a small country, most beekeepers are pretty near another beekeeper, which means there is usually someone not too far away to provide advice. And we have our fantastic National Bee Unit inspectors too, who will come out to see hives if a notifiable disease like American or European foul brood is suspected, as well as running Bee Health Day workshops to train beekeepers on spotting diseases. I wonder how much this good training and support network contributes to the high overwinter survival rate.

Below are some of the English stats, from their BBKA News magazine.

BBKA Annual overwinter survival rates in England
BBKA Annual overwinter survival rates in England by region

Lego characters: Librarian, IT geek and Beegirl. Just because.

Posted in beekeeping, Uncategorized | Tagged | 19 Comments

Bees, bees everywhere

It was a hot summer’s evening. I stuck my head out of our attic window and looked down the hill over Truro as the sun came down. The cathedral spire in the distance, pastel pink, blue and cream rhododendrons in the garden opposite. Seagulls swooshed through the sky and the blackbirds sang goodnight.

I turned my head to the right and a familiar silhouette caught my eye. It landed on the chimney, dark against the sky. First one, then another, then another. Not just one honey bee out alone. A colony. An entrance.

My eyes travelled down the chimney pot and my mind travelled back to Drew telling me our wood fired burner had stopped working – he thought there seemed to be some kind of blockage in the chimney. He had tried to look up there, but couldn’t see anything.

The bees continued to land, buffeted about by the rooftop wind as they returned home. The colony look strong. Did they know this was a beekeeper’s house?

Since discovering the bees I have been trying to think about what I can do to persuade them to leave the chimney. Even if I could safely get up on the roof, I suspect they will be inside a cavity only bees can reach. There was a post by a beekeeper on the British and Irish Beekeepers group who had done a chimney removal – as well as being a beekeeper, he also happened to have “qualifications in working at height, PASMA, CSCS, Asbestos trained…a MEWPS licence…Gas Acop Certified”. I don’t even know what most of those qualifications are, but I know I don’t have them!

Having read more, I do know that we should definitely not start a fire underneath. That can be dangerous and cause a flash fire, as all the honey and wax will melt and run down.

I think the best solution is leaving the bees up there, as I expect without varroa treatment the colony will not keep on going indefinitely. Then we can have a look at removing the comb, so that new swarms are not attracted to it. If anyone has any other suggestions, please do let me know!

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Tips from Cornwall’s Bee Health Day 2019: How to keep healthy bees

I enjoyed Bee Health Day at the weekend – it’s an annual day run by the two Cornwall Beekeeping Associations (CBKA and WBKA) and the National Bee Unit Bee Inspectors. There are talks on keeping healthy bees, varroa and the Asian hornet as well as a practical apiary session and the chance to look at some diseased foulbrood combs up close. We were at the University of Exeter’s Penryn campus, which has a team of talented bee researchers led by Professor Juliet Osbourne and some incredibly beautiful flower displays. Here’s my notes from the day.

Bee health introduction

David, one of Devon’s Bee inspectors, gave us a quick intro into how to keep healthy bees. He reminded us that beekeepers are usually the number one culprit for spreading disease. You should:

  • Wash your suit and hive tools with washing soda between each apiary visit
  • Take a bucket with washing soda solution to the apiary and wash your tools in it between inspecting different hives
  • Use disposable gloves – or Marigolds which can be washed in washing soda
  • Avoid swapping frames between apiaries. He told us about a commercial beekeeper who extracted honey from hives and then gave the frames back to hives in different apiaries to clean up. The beekeeper got disease in every single hive. Mark your super frames and give them back to the same colony to clean up after extracting. Don’t leave super frames out in the open for bees to clean up.
  • Aim to change your brood frames every 1-3 years. The inspectors have quite different views between them about how to do this. David greatly favours shook-swarming whereas one of the Cornish inspectors, Eric, dislikes shook-swarming. Eric gets his bees to draw out a brood box worth of brood frames each spring (with a queen excluder underneath so no brood is laid in it) and then distributes these between colonies to gradually replace a few frames each year.
  • Twice a year inspect the brood combs solely for disease, rather than focusing on the usual things like whether the queen is laying or looking for queen cells etc.

Inspect brood comb regularly for brood disease. Courtesy The Food and Environment Research Agency (Fera), Crown Copyright.

Varroa workshop

Something called something like ‘Parasitic mite syndrome’, which is probably spread by varroa, is a problem at the moment. The symptoms are:

  • Brood dying in capped cells
  • Colony breaking down (because it’s struggling to produce healthy new bees)

I’ve written more about this in the practical apiary notes underneath.

The inspectors also mentioned that they’re also seeing a lot of Chronic Bee Paralysis Virus (CBPV) this year. The rainy weather may be behind this as when bees are cooped up inside their hive for longer periods than usual hairs are broken from their cuticles, allowing CBPV to spread from diseased bees to healthy bees in the exposed gaps.

Open mesh floors

I was interested to hear about a paper by Harris & Harbo (2004) – ‘Effect of screen floors on populations of honey bees and parasitic mites‘ which found that 0pen mesh floors (or open screen floors as they’re called in the US) cause adult varroa mites to stay on the adult bees longer, so they reproduce less regularly inside the brood cells. It’s not known why this is. However, open mesh floors are definitely A Good Thing when it comes to keeping mite levels down – every little helps.


This was mentioned as the only authorised treatment in this country which can be used with honey supers on. The inspector running the varroa workshop asked if anyone had used it – one person said “Yes… never again”.

The inspector told us that he’d been called out this year to a beekeeper who used MAQs in March on his 12 colonies – 9 out of the 12 queens failed afterwards. He suspected too much treatment had been used. With MAQs the instructions must be followed to the letter as it’s very powerful stuff.

Thymol treatment

The inspector recommended rotating thymol treatments each year, even though there’s less chance of resistance with thymol as it attacks varroa mites in a number of different ways.

He’s a fan of Apiguard (as am I). The queen will go off lay while you treat with Apiguard, but this can be seen as an advantage in reducing mite numbers.

An audience member commented that he had more success with Apiguard in his double brood box hives when he put the trays between the two brood boxes rather than at the top. He didn’t use an eke, just put the tray under the brood frame bee space.


Apiguard treatment

Oxalic acid

Someone asked how oxalic acid works – how does it kill mites? The answer was that we don’t know how it works yet, just that it does! Even the manufacturers of oxalic acid based treatments don’t know at the moment. There are various theories such as that the acid burns the mouthparts of the mites, causing them to fall off the adult bees, but nothing has been conclusively proven yet.

When trickling you need to keep the mixture warm to avoid chilling the bees, so the inspector uses a cool bag with a hot water bottle in to keep it warm. He commented that the HMF levels in pre-mixed treatment do build up and he wondered whether the HMF levels in the old pre-mixed trickles (which Thornes and other suppliers sold a few years ago) must have been quite toxic to the bees. Only make up the oxalic acid mixture just before you intend to use it.

Apibioxal drizzling

Apibioxal drizzling

PolyVar Yellow

I hadn’t heard of this before, but PolyVar yellow is a plastic mouse guard which gives the bees a flumethrine treatment as they squeeze through it. Shouldn’t be left on longer than nine weeks and not while honey supers are on. There were some concerns that it might knock pollen off but this doesn’t appear to happen.

Apiary inspection

We had the privilege of watching one of the inspectors look inside a hive belonging to the University of Exeter – I think I was in Eric James’ group.

Miraculously, it wasn’t raining!! It was even warm enough to sit outside without coats on (not a given in a Cornish summer).

The hive Eric inspected was struggling. It had two supers with plenty of honey and bees in them. And yet… inside the brood box the bees were only on about four frames. They had been shook-swarmed in May due to disease and seemed not to have built up again since (perhaps not surprising after a month of rain). Judging by the smell of thymol they’d also been treated for varroa with a thymol-based treatment, which may have knocked them back too.

Eric opened up some of the brood and showed us dead bees within apparently healthy looking capped brood cells which hadn’t hatched. He said the inspectors had some disagreement between them over what this was being caused by. David, the Devon bee inspector, would call it the Parasitic mite virus mentioned earlier, whereas he thought it was something new and not named yet.

Whatever it is, it’s being discovered in hives across the country. They are at a loss on how to treat it – getting the bees on new comb doesn’t seem to help. It may be transmitted by the queen or in the sperm of the drones. Some of the brood will be healthy and hatch, whereas there will be patches where the brood doesn’t and the bees will be dead inside the cells. Sometimes you will see rough perforated cappings where the bees have started opening up the cappings to try to remove the dead larvae.

After the apiary was lunch. We had been warned to bring our own packed lunch, but in the rush of leaving the house with a toddler I’d only packed a tiny croissant. “No problem”, I thought, “I’ll go to the campus shop”. I had walked past this on the way and seen a sign which said it opened at 10am on Saturdays. It was about a ten minute walk back to the shop… which was in darkness. It was then that I saw another sign underneath which said the shop was now closed on weekends. I walked to another far flung part of the campus and asked the reception staff there if there was any food about, but they told me there was none at all for sale anywhere on campus and even the one vending machine was broken. It’s a weakness of mine that I don’t function well when I’m hungry, so at this point I gave up and got the train home just so I could get some food! Unfortunately this meant I missed the diseased combs and Asian hornet workshops – next year I will make sure to pack an extra big packed lunch.

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Going on a (mini) bee safari

Last weekend I went on a very enjoyable mini bee safari at the home of two Cornwall Beekeepers Association members. For their privacy I won’t give any names and shall just say the location was central Cornwall.

A bee safari means you get to look in other people’s hives and then enjoy a cup of tea afterwards while talking about bees. The perfect way to spend a sunny morning, no?

Brood box

Brood box

There was a wide spectrum of beekeeping experience between us all, ranging from those who had never held a frame before to experienced beekeepers of many stings. The beginners were able to inspect through a hive for the first time and see a range of different beekeeping dilemmas.

Queen excluder

I do like these sturdy queen excluders.

Bees at entrance

Bees at the entrance

It was particularly interesting to look inside a hive which was possibly queenless – our host wasn’t sure. On one of the first frames, multiple eggs in some cells were observed. It was discussed that this was likely to be laying workers, as while the eggs were at the bottom of the cells, they were considered to be short cells.

After some discussion about what could be done to rescue this hive full of laying workers, one of our hosts raised an objection – she had spotted some cells which had just one egg at the bottom. Were we sure this hive was queenless?

The next frame was lifted out for inspection. This contained a mixture of capped and uncapped brood. Case closed and no action needed! Just to confirm things even further, queenie was spotted and efficiently marked in a sponge plunger style cage. I was pleased to see this demonstrated as I bought one of these cages recently, having only used the crown of thorns style press-in cage before. The trickiest part of the process was getting the queen in, as she was quite a runner. It was commented that this was a two person job – one person to hold the frame up, the other to catch the queen in the cage.

Ron Mishka’s recent blog post ‘At least one of these bees is a laying worker‘ has a good explanation of how laying workers come about, how to tell the difference between a laying worker and a newly laying queen and what to do about laying workers. Even if you know all this already, you should follow Ron’s blog because it’s great!

The pleasurable morning was capped off by tea and coffee accompanied by multiple types of home made cake – rock cakes (delicious), cheese scones which one person commented were among the best they’d ever had, a cake I think contained honey… plus biscuits and wrapped mini swiss rolls.

Back at my hives, my spring of bee chaos continues. I’ve combined one of the weak swarm nucs into my strong yellow colony, as it seemed to be queenless and struggling. The nuc you see on the left also seemed to be queenless, so I gave it a test frame of eggs. When I inspected last week they had created a capped queen cell from the test frame – but I stupidly turned the frame over to inspect it without thinking, which may have dislodged the growing queen. I realised my mistake the instant I turned it upside down 😦

Apiary shot

The nuc you see below is my strong one, and the only colony I have in which the queen is really going for it with laying. I’ve taken two test frames of eggs from this so far! Thank you queenie – at some point I’ll have to give you a name.

Painted poly nuc

Painted poly nuc

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