The flow must go on

Except it doesn’t ūüôĀ

And once the summer nectar flow is over, the honey ripened and the supers safely removed it is time to prepare the colonies for the winter ahead.

It might seem that mid/late August is very early to be thinking about this when the first frosts are probably still 10-12 weeks away. There may even be the possibility of some Himalayan balsam or, further south than here in Fife, late season ivy.

However, the winter preparations are arguably the¬†most important time in the beekeeping year. If you leave it too late there’s a good chance that colonies will struggle with disease, starvation or a toxic combination of the two.

Long-lived bees

The egg laying rate of the queen drops significantly in late summer. I used this graph recently when discussing drones, but look carefully at the upper line with open symbols (worker brood). This data is for Aberdeen, so if you’re beekeeping in Totnes, or Toulouse, it’ll be later in the calendar. But it will be a broadly similar shape.

Seasonal production of sealed brood in Aberdeen, Scotland.

Worker brood production is down by ~75% when early July and early September are compared.

Not only are the numbers of bees dropping, but their fate is very different as well.

The worker bees reared in early July probably expired while foraging in late August. Those being reared in early September might still be alive and well in February or March.

These are the ‘winter bees‘ that maintain the colony through the cold, dark months so ensuring it is able to develop strongly the following spring.

The purpose of winter preparations is threefold:

    1. Encourage the colony to produce good numbers of winter bees
    2. Make sure they have sufficient stores to get through the winter
    3. Minimise Varroa levels to ensure winter bee longevity

I’ll deal with these in reverse order.

Varroa and viruses

The greatest threat to honey bees is the toxic stew of viruses transmitted by the Varroa mite. Chief amongst these is deformed wing virus (DWV) that results in developmental abnormalities in heavily infected brood.

DWV is well-tolerated by honey bees in the absence of Varroa. The virus is probably predominantly transmitted between bees during feeding, replicating in the gut but not spreading systemically.

However, Varroa transmits the virus when it feeds on haemolymph (or is it the fat body?), so bypassing any protective immune responses that occur in the gut. Consequently the virus can reach all sorts of other sensitive tissues resulting in the symptoms most beekeepers are all too familiar with.

Worker bee with DWV symptoms

Worker bee with DWV symptoms

However, some bees have very high levels of virus but no overt symptoms 1.

But they’re not necessarily healthy …

Several studies have clearly demonstrated that colonies with high levels of Varroa and DWV are much more likely to succumb during the winter 2.

This is because deformed wing virus reduces the longevity of winter bees. Knowing this, the increased winter losses make sense; colonies die because they ‘run out’ of bees to protect the queen and/or early developing brood.

I’ve suggested previously that isolation starvation may actually be the result of large numbers of winter bees dying because of high DWV levels.¬†If the cluster hadn’t shrunk so much they’d still be in contact with the stores.

Even if they stagger on until the spring, colony build up will be slow and faltering and the hive is unlikely to be productive.

Protecting winter bees

The most read article on this site is When to treat? This provides all the gory details and is worth reading to get a better appreciation of the subject.

However, the two most important points have already been made in this post. Winter bees are being reared from late August/early September and their longevity depends upon protecting them from Varroa and DWV.

To minimise exposure to Varroa and DWV you must therefore ensure that mite levels are reduced significantly in late summer.

Since most miticides are incompatible with honey production this means treating very soon after the supers are removed 3.

Time of treatment and mite numbers

Time of treatment and mite numbers

Once the supers are off there’s nothing to be gained by delaying treatment … other than more mite-exposed bees ūüôĀ

In the graph above the period during which winter bees are being reared is the green arrow between days 240 and 300 (essentially September and October). Mite levels are indicated with solid lines, coloured according to the month of treatment. You kill more mites by treating in mid-October (cyan) but the developing winter bees are exposed to higher mite levels.

In absolute numbers more mites are present and killed because they’ve had longer to replicate … on your developing winter bee pupae ūüôĀ

Full details and a complete explanation is provided in When to treat?

So, once the supers are off, treat as early as is practical. Don’t delay until late September or early October 4.

Treat with what?

As long as it’s effective and used properly I don’t think it matters too much.

Amitraz strip placed in the hive.

Apiguard if it’s warm enough. Apistan if there’s no resistance to pyrethroids in the local mite population (there probably will be ūüôĀ ). Amitraz or even multiple doses of vaporised oxalic acid-containing miticide such as Api-Bioxal¬†5.

This year I’ve exclusively used Amitraz (Apivar). It’s readily available, very straightforward to use and extremely effective. There’s little well-documented resistance and it does not leave residues in the comb.

The same comments could be made for Apiguard though the weather cannot be relied upon to remain warm enough for its use here in Scotland.

Another reason to not use Apiguard is that it is often poorly tolerated by the queen who promptly stops laying … just when you want her to lay lots of eggs to hatch and develop into winter bees 6.

Feed ’em up

The summer nectar has dried up. You’ve also removed the supers for extraction.

Colonies are likely to be packed with bees and to be low on stores.

Should the weather prevent foraging there’s a real chance colonies might starve 7 so it makes sense to feed them promptly.

The colony will need ~20 kg (or more) of stores to get through the winter. The amount needed will be influenced by the bees 8, the climate and how well insulated the hive is.

I only feed my bees fondant. Some consider this unusual 9, but it suits me, my beekeeping … and my bees.

Bought in bulk, fondant (this year) costs £10.55 for a 12.5 kg block. Assuming there are some stores already in the hive this means I need one to one and a half blocks per colony (i.e. about £16).

These three photographs show a few of the reasons why I only use fondant.

  • It’s prepackaged and ready to use. Nothing to make up. Just remove the cardboard box.
  • Preparation is simplicity itself … just slice it in half with a long sharp knife. Or use a spade.
  • Open the block like a book and invert over a queen excluder. Use an empty super to provide headroom and then replace the crownboard and roof.
  • That’s it. You’re done. Have a holiday ūüėČ
  • The timings shown above are real … and there were a couple of additional photos not used. From opening the cardboard box to adding back the roof took¬†less than 90 seconds. And that includes me taking the photos¬†and cutting the block in half ūüôā
  • But equally important is what is¬†not shown in the photographs.
    • No standing over a stove making up gallons of syrup for days in advance.
    • There is no specialist or additional equipment needed. For example, there are no bulky syrup feeders to store for 48 weeks of the year.
    • No spilt syrup to attract wasps.
    • Boxed, fondant keeps for ages. Some of the boxes I used this year were purchased in 2017.
    • The empty boxes are ideal for customers to carry away the honey they have purchased from you ūüėČ
  • The final thing not shown relates to how quickly it is taken down by the bees and is discussed below.

I’m surprised more beekeepers don’t purchase fondant in bulk through their associations and take advantage of the convenience it offers. By the pallet-load delivery is usually free.

Fancy fondant

Capped honey is about 82% sugar by weight. Fondant is pretty close to this at about 78%. Thick syrup (2:1 by weight) is 66% sugar.

Therefore to feed equivalent amounts of sugar for winter you need a greater weight of syrup. Which – assuming you’re not buying it pre-made – means you have to prepare and carry large volumes (and weights) of syrup.

Meaning containers to clean and store.

But consider what the bees have to do with the sugar you provide. They have to take it down into the brood box and store it in a form that does not ferment.

Fermenting stores can cause dysentry. This is ‘a bad thing’ if you are trapped by adverse weather in a hive with 10,000 close relatives … who also have dysentry. Ewww ūüėĮ

To reduce the water content the bees use space and energy. Space to store the syrup and energy to evaporate off the excess water.

Bees usually take syrup down very fast, rapidly filling the brood box.

In contrast, fondant is taken down more slowly. This means there is no risk that the queen will run out of space for egg laying. Whilst I’ve not done any side-by-side properly controlled studies – or even improperly controlled ones – the impression I have is that feeding fondant helps the colony rear brood into the autumn 10.

Whatever you might read elsewhere, bees do store fondant. The blocks I added this week will just be crinkly blue plastic husks by late September, and the hives will be correspondingly heavier.

You can purchase fancy fondant prepared for bees with pollen and other additives.

Don’t bother.

Regular ‘Bakers Fondant’ sold to ice Chelsea buns is the stuff to use. All the colonies I inspect at this time of the season have ample pollen stores.

I cannot comment on the statements made about the anti-caking agents in bakers fondant being “very bad for bees” … suffice to say I’ve used fondant for almost a decade with no apparent ill-effects 11.

It’s worth noting that these statements are usually made by beekeeping suppliers justifying selling “beekeeping” fondant for ¬£21 to ¬£36 for 12.5 kg.

Project Fear?


Colophon

The title of this post is a mangling of the well-known phrase The show must go on. This probably originated with circuses in the 19th Century and was subsequently used in the hotel trade and in show business.

The show must go on is also the title of (different) songs by Leo Sayer (in 1973, his first hit record, not one in my collection), Pink Floyd (1979, from The Wall) and Queen (1991).

Women without men

The title of the post last week was The end is nigh which, looking at the fate of drones this week, was prophetic.

Shallow depth of field

Watch your back mate … !

After the ‘June gap’ ended queens started laying again with gusto. However, there are differences in the pattern of egg laying when compared to the late spring and early summer.

Inspections in mid/late August 1 show clear signs of colonies making preparations for the winter ahead.

For at least a month the amount of drone brood in colonies has been reducing (though the proportions do not change dramatically). As drones emerge the cells are being back-filled with nectar.

Seasonal production of sealed brood in Aberdeen, Scotland.

The data in the graph above was collected over 50 years ago 2. It remains equally valid today with the usual caveats about year-to-year variation, the influence of latitude and local climate.

Drones are valuable …

Drones are vital to the health of the colony.

Honey bees are polyandrous, meaning the queen mates with multiple males so increasing the genetic diversity of the resulting workers.

There are well documented associations between colony fitness and polyandry, including improvements in population growth, weight gain (foraging efficiency) and disease resistance.

The average number of drones mating with a queen is probably somewhere between 12 and 15 under real world conditions. However studies have shown that hyperpolyandry further enhances the benefits of polyandry. Instrumentally inseminated queens “mated” with 30 or 60 drones show greater numbers of brood per bee and reduced levels of¬†Varroa infestation.

Why don’t queens¬†always mate with 30-60 drones then?

Presumably this is a balance between access, predation and availability of drones. For example, more mating would likely necessitate a longer visit to a drone congregation area so increasing the chance of predation.

In addition, increasing the numbers of matings might necessitate increasing the number of drones available for mating 3.

… and expensive

But there’s a cost to increasing the numbers of drones.

Colonies already invest a huge amount in drone rearing. If you consider that this investment is for colony reproduction it is possible to make comparisons with the investment made in workers for reproduction i.e. the swarm that represents the reproductive unit of the colony.

Comparison of the numbers of workers or drones alone is insufficient. As the graph above shows, workers clearly outnumber drones. Remember that drones are significantly bigger than workers. In addition, some workers are not part of the ‘reproductive unit’ (the swarm).

A better comparison is between the dry weight of workers in a swarm and the drones produced by a colony during the season.

It’s worth noting that these comparisons must be made on colonies that make as many drones as they want. Many beekeepers artificially reduce the drone population by only providing worker foundation or culling drone brood (which I will return to later).

In natural colonies the dry weight of workers and drones involved in colony reproduction is just about 1:1 4.

Smaller numbers of drones are produced, but they are individually larger, live a bit longer and need to be fed through this entire period. That is a big investment.

Your days are numbered

And it’s an investment that is no longer needed once the swarming season is over. All those extra mouths that need feeding are a drain on the colony.

Even though the majority of beekeepers see the occasional drone in an overwintering colony, the vast majority of drones are ejected from the hive in late summer or early autumn.

About now in Fife.

In the video above you can see two drones being harassed and evicted. One flies off, the second drops to the ground.

As do many others.

There’s a small, sad pile of dead and dying drones outside the hive entrance at this time of the season. All perfectly normal and not something to worry about 5.

Drones are big, strong bees. These evictions are only possible because the workers have stopped feeding them and they are starved and consequently weakened.

A drone’s life … going out with a bang … or a whimper.

An expense that should be afforded

Some of the original data on colony sex ratios (and absolute numbers) comes from work conducted by Delia Allen in the early 1960’s.

Other colonies in these studies were treated to minimise the numbers of drones reared. Perhaps unexpectedly these colonies did not use the resources (pollen, nectar, bee bread, nurse bee time etc) to rear more worker bees.

In fact, drone-free or low-drone colonies produced more bees overall, a greater weight of bees overall and collected a bit more honey. This strongly suggests that colonies prevented from rearing drones are not able to operate at their maximum potential.

This has interesting implications for our understanding of how resources are divided between drone and worker brood production. It’s obviously not a single ‘pot’ divided according to the numbers of mouths to feed. Rather it suggests that there are independent ‘pots’ dedicated to drone or worker production.

Late season mating and preparations for winter

The summer honey is off and safely in buckets. Colonies are light and a bit lethargic. With little forage about (a bit of balsam and some fireweed perhaps) colonies now need some TLC to prepare them for the winter.

If there’s any reason to delay feeding it’s important that colonies are not allowed to starve. We had a week of bad weather in mid-August. One or two colonies became dangerously light and were given a kilogram of fondant to tide them over until the supers were off all colonies and feeding and treating could begin. I’ll deal with these important activities next week.

In the meantime there are still sufficient drones about to mate with late season queens. The artificial swarm from strong colony in the bee shed was left with a charged, sealed queen cell.

Going by the amount of pollen going in and the fanning workers at the entrance – see the slo-mo movie above – the queen is now mated and the colony will build up sufficiently to overwinter successfully.


Colophon

Men without Women

Men without women was the title of Ernest Hemingway’s second published collection of short stories. They are written in the characteristically pared back, slightly macho and bleak style that Hemingway was famous for.

Many of these stories have a rather unsatisfactory ending.

Not unlike the fate of many of the drones in our colonies.

Women without men is obviously a reworking of the Hemingway title which seemed appropriate considering the gender-balance of colonies going into the winter.

If I’d been restricted to writing using the title¬†Men without Women I’d probably have discussed the wasps that plague our picnics and hives at this time of the year. These are largely males, indulging in an orgy of late-season carbohydrate bingeing.

It doesn’t do them any good … they perish and the hibernating overwintering mated queens single-handedly start a new colony the following spring.

The end is nigh

A brief triptych of items this week as I’m struggling with an intermittent broadband connection on the remote west coast 1.

Great view but no signal

There are worse places to be cutoff …

Summer honey

There are no significant amounts of heather in central Fife and there’s none within range of my colonies. Work and other commitments mean it’s not practical to take my colonies to the Angus glens, so when the summer nectar flow finishes so does my beekeeping season.

The summer honey I produce is clear, runny honey. It is best described as mixed floral or blossom honey. In some years it has a significant amount of lime in it.

Lime honey has a greenish tinge and a wonderful zesty flavour. In other years it lacks the lime but is no less delicious.

Honey

Honey

Last year it was “Heinz”¬†honey¬†i.e. 57 varieties. I looked at the pollen content during the excellent Scottish Beekeepers Microscopy course and there was a very wide range of tree and flower pollens, most of which remained unidentified.

What was striking was the relative abundance of pollen in contrast to the ‘control’ samples of supermarket honey. Most of these had probably been subjected to significant filtration during processing.

I’ll return to pollen in honey, and more specifically pollen in¬†local honey shortly.

Following a judicious amount of ‘on the spot’ testing (i.e. dipping my finger into broken honey comb and tasting ūüėČ ) some of the honey this year has the ‘lime zest’ and, with the flow over, it’s now time to collect it for extraction.

Clearing supers

Towards the end of the summer colonies should be strong. A double brood National hive with three or four supers contains a lot of bees.

To remove the supers it’s first necessary to remove the bees.

Porter bee escape

Some beekeepers use smelly pads to achieve this, some use modified leaf blowers and many use a crownboard with a Porter bee escape (a sort of one-way valve for bees).

I’ve never liked the idea of putting a¬†non-toxic blend of natural oils and herb extracts (the description of Bee Quick) anywhere near my delicately flavoured honey. I know most is capped. However, I want to avoid any risk of tainting the final product.

A leaf blower seems pretty barbaric to me. Shaking bees off the super frames leaves a lot of disorientated bees flying around the apiary. Blasting them halfway to the other side of the field is a poor way to thank them for all their hard work over the last few weeks.

I described the Porter bee escape as a ‘sort of’ one way valve. That’s because they don’t always work dependably. Big fat drones (why were they in the supers anyway?) get stuck, they get jammed with propolis and they’re very inefficient.

Clearer boards

Clearer boards …

I use a simple clearer board with no moving parts, two large ‘entrances’ and two very small ‘exits’. These clear a stack of supers overnight.

I don’t have enough for all my hives 2 so clear a few at a time.

I stack the supers on top of my honey warming cabinet set at 34¬įC. This delays crystallisation 3 and significantly improves the efficiency of extraction as the honey flows much more easily.

Honey filled supers

Honey filled supers …

Before leaving the subject of clearing supers it’s worth remembering that colonies can get a bit tetchy once the flow is over. Don’t be surprised if they don’t thank you for pinching all their hard earned stores.

In addition, it is very important to avoid spilling honey from broken comb or exposing colonies – particularly weak ones – which may induce robbing.

I prefer to  add the clearers in good weather and then remove the supers in poor weather the following day, or early or late the next day. Both ensure that there are fewer bees about.

Local honey

I get a lot of requests for ‘local honey’. Many of these are to alleviate or prevent hay fever. This is based on the belief that the pollen in honey primes the immune system and prevents the adverse responses seen in hay fever.

Despite the lack of scientific evidence supporting any beneficial effect, the repeated anecdotal evidence is reassuring … and certainly helps honey sales ūüėČ

Le client n’a jamais tort4

And, whether it helps hay fever or not, it certainly tastes good ūüôā

I only produce local honey, but am regularly asked for more details.

Where do the bees forage? How far do they fly?

What is local anyway?

British?

Scottish?

Fife?

Certainly not the first two, even if we do all now live in the global village¬†5.¬†Local means ‘the neighbourhood’ or a particular area.

Area, of course, isn’t defined.

It might not even mean Fife. The honey produced from the town gardens in St Andrews or Dunfermline will be different from the honey produced from the small villages in the flat agricultural land of the Howe of Fife.

Fife and Kinross Shires Civil Parish map

And the honey produced in the spring is very different from summer honey, or in different years.

There’s a lot of interest in eating locally produced food. Just consider the millions of posts using the hashtags #eatlocal on Twitter or Instagram.

Artisan shops that sell local produce tend to sell it at a significant premium. That’s something worth remembering ūüėČ Customers are prepared to pay more because they know something about the provenance of the produce, or they want to be reassured it has not been transported half way across the globe.

For those who want more information about ‘local’ honey, it would be good to be able to provide it – even if they purchase it in a shop 6. For those who don’t, who aren’t interested, or who just want to spread it thickly on toast 7 then the information is superfluous and should not spoil the appearance of the jar or label.

I’ve been toying with solutions to this over the last couple of years. It provides a bee-related diversion during the long winter evenings.

Some of the commercial Manuka honey producers already have a labelling system that incorporates links to this sort of additional information. With a bit of interweb geekery, a suitable server and a functioning broadband connection it should be relatively straightforward to engineer.

Watch this space …

But for the moment this will have to wait … I have honey supers to collect and no functioning broadband ūüôĀ


 

Queen includer

By definition the queen excluder should be an impassable barrier for the queen.

“Why not put one under the brood box 1¬†to prevent the loss of a swarm?”, asks the beginner beekeeper.

Framed wire QE ...

Framed wire QE …

A perfectly logical question, and one to which you will hear 2 a variety of answers. These include the adverse effect on pollen collection, the possibility of an undersize virgin getting through anyway (with the loss of a swarm) and the distressing consequences it has for drones in the hive.

The late David Cushman covers these and other reasons.

Just because you probably shouldn’t, doesn’t mean you can’t … and this is what happens when you do.

Hot and bothered

I recently discussed my current thoughts on using a bee shed for teaching purposes. In it I made the point that it can get unbearably hot in a beesuit on a warm day.

Phew!

A couple of weeks ago I spent a sweltering hour or so inspecting the seven colonies in our larger shed.

It’s midsummer. It was a hot sunny day and the shed thermometer was reading over 32¬įC.

Some of the colonies were on double brood and had at least three supers on.¬†Those that didn’t were recently installed and were a bit “temperamental”. These are research colonies and they came from a collaborator 3.

One colony should have recently requeened and I wanted to find, mark and clip her before the colony built up again.

I worked my way through the single boxes first. I found the queen in each of them except the one that had requeened.

Typical ūüôĀ

My excuse was that I was half-blind with sweat. However, it’s not unusual to not find the queen when you actually need to 4.

I didn’t dally, I still had the 5-6 box towers to get through.

The tower of power

In my dreams

Finally I was left with colony #6. This had been strong from the start of the season and was now probably the strongest hive in the apiary. The double brood box was bulging with bees with at least 18 frames of brood in all stages.

The supers were very heavy.

At the beginning of the afternoon I’d intended to find the queen and prepare the box to be split once the flow was over (any day now). However, after more than an hour in stifling conditions I was struggling and starting to hallucinate about ice cold beer.

Inevitably I couldn’t find the queen ūüôĀ

With sweat stinging my eyes and dripping off my nose onto the inside of the veil I could barely see the comb, let alone the queen. I did find eggs, so I knew she was present (or had been 2-3 days ago) and there were no obvious signs of swarm preparation. The colony was very busy, but the queen definitely still had space to lay.

I decided to pop a queen includer excluder between the brood boxes with the intention of returning 3-4 days later to look for eggs as an indicator of where the queen was.

I packed up, returned home and slaked my thirst.

Oh no they’re not … Oh yes they are …

Two days later my PhD student calls me from the apiary to tell me that colony #6 is swarming.

“Oh no they’re not … I checked them a couple of days ago and all was well”, I replied smugly.

But of course I visited the apiary to check anyway.

They were swarming ūüôĀ

Oh yes they are!

Unlike a ‘typical’ swarm this appeared to have no centre or focus (where I’d usually expect to find the queen). The bees were spread over a wide area, hanging in a large clump under the landing board and on the edges and corners of the shed.

They weren’t clustering in any real sense of the word, but they also weren’t re-entering the hive.

I had a prod about around the entrance looking for the queen, gently removing handfuls of bees. The bees were very calm as you usually expect of swarms 5 and I could move them aside in my search.

But there was no sign of her.

Bees fanning at the hive entrance .. obviously a different hive as I had my hands full with the swarm.

However, there were a number of bees fanning busily at the hive entrance. Each was facing the entrance with the abdomen pointing up and away from the hive and the Nasanov gland exposed at the tip of the abdomen.

The Nasonov pheromone is a mix of terpenoids that attracts workers. It is left as an attractant by honey bees on nectar-rich flowers and – when produced by fanning bees at the hive entrance – it is usually a good indication that the queen is inside.¬†An artificial version forms the commercial ‘swarm lure’ you can buy.¬†

What’s (probably) in the box?

By now I could make a fair guess at what had happened.

I assumed the queen was somewhere in the double brood box, either because she was clipped and had returned there or because she was trapped above the queen excluder.

Or, of course, both 6.

They’d presumably swarmed because I’d missed a queen cell.¬†D’oh!

I therefore expected to find both a queen and one or more queen cells in the box … and I needed to quickly make a decision about how to resolve the situation.

Swarm control rescue

Pagdens' artificial swarm ...

Pagdens’ artificial swarm …

Swarm control usually refers to a hive manipulation that prevents the colony from swarming. For example, the classic Pagden artificial swarm.

Despite the fact that this colony had swarmed 7, if I could find the queen I could divide the colony like a Pagden artificial swarm and (hopefully) rescue the situation.

I removed the supers and put them to the side. I assembled a new floor and brood box with 10 mixed frames 8 and substituted this for the original floor and double brood box.

I took the double brood box outside 9, separated the two boxes and went through them carefully.

The¬†upper box contained the queen … above the queen excluder. I put her on the frame she occupied back into the new empty brood box in the shed.

The¬†lower box had a handful of queen cells along the edge of a partially drawn foundationless frame. I’d missed these in the previous inspection. I’ll blame it on the heat, but I may need to visit Specsavers

I added a queen excluder to the new brood box and carefully placed the supers back on top. All the flying bees, which includes the foragers, would return to the original location within a day or two so the supers were there if the flow continued.

All’s well that ends well

I inspected the colonies a few days later. The queenright colony in the original location in the shed was busy, the queen was laying the well 10 and there was still nectar coming in.

I carefully went though the queenless colony to see if there were any additional queen cells and knocked all back except one which I know was charged (i.e. contained a developing larvae).

With a bit of good weather there should be a new mated queen in the box by mid/late August. If there isn’t I’ll unite the colony back with the one containing the original queen.

Lessons learned

As always there are lessons to be learned. The lessons this time are reasonably obvious:

  • Expiring from heat exhaustion is no reason to cut corners when inspecting a colony. I wasn’t aware that I’d cut corners, but the queen cells were reasonably obvious and would have been more than play cups at inspection 11. Perhaps I should have left it for a cooler day? But perhaps they would have then swarmed anyway … ? Beekeeping might appear like a gentle pastime (and it can be), but it can also be very hard work.
  • Moving a strong colony away from its original location usually helps reduce the bee numbers, so making inspections easier. This was undoubtedly helped by the absentee swarming bees as well 12.
  • Be prepared. Keep spares in the apiary so you can deal with the unexpected without making a return trip. I always try and keep a bait hive in the apiary and happily steal any or all of it to deal with these sorts of situations. You can always replace the bait hive at your leisure. Inevitably a busy swarm season can deplete your spares and it’s always worth remembering that the bees will cope with all sorts of sub-standard accommodation for a short period. A piece of ply as a roof, a crownboard as a floor (assuming it has a hole in it!), two stacked supers rather than a brood box, no crownboard (perhaps because it’s being used as a floor), an incomplete box of frames¬†etc. Improvise if you need to …¬†the bees will not mind.

Queen includers

Instead of a queen excluder, Thorne’s sell a “swarm trap” that consists of a box to fit over the hive entrance which has both a queen excluder¬†and an exit for drones. They market it as being¬†developed with the hobby beekeeper in mind who finds weekly inspections to remove queen cells almost impossible.

Swarm trap

I’ve not seen one in use so cannot comment on it. However, in my opinion there’s¬†“no gain without pain” … if you are going to keep bees you need to appreciate that the principles of the hobby involve the need for regular inspections. It would probably be better to just purchase local honey rather than relying on this type of swarm trap for missed inspections.

Some beekeepers place a queen excluder under a brood box after hiving a captured swarm onto undrawn foundation. This helps prevent the colony from absconding while the bees draw some comb. After that the queen will start laying and the risk of the swarm disappearing is much reduced.

I’ve never used a queen excluder like this as I don’t routinely collect swarms. Those I acquire generally arrive under their own steam in a bait hive. Since these already have one drawn comb a mated queen can start laying without delay.

I don’t ever remember having a swarm from a bait hive abscond. Casts (a swarm with an unmated queen) also seem to stay if they have chosen their destination and moved there voluntarily.

The alternative way to encourage a hived swarm to stay put is to give them a frame of open brood. I have done this but prefer not to 13 as I treat all swarms with a miticide soon after they are hived to reduce Varroa levels. To ensure this treatment is really effective I want to be certain there is no sealed brood in the hive.


 

Virus resistant bees?

In the early/mid noughties there was a lot of excitement about a newly discovered pathogen of honey bees, Israeli Acute Paralysis Virus (IAPV). This virus was identified and initially characterised in 2004 and, a couple of years later, was implicated as the (or at least a) potential cause of Colony Collapse Disorder (CCD) 1..

CCD is, and remains (if it still exists at all), enigmatic 2. It is an oft-misused term to describe the dramatic and terminal reduction in worker bee numbers in a colony in the absence of queen failures, starvation or obvious disease. It primarily occurred in the USA in 2006-07 and was reported from other countries in subsequent years 3.

Comparisons of healthy and CCD-affected colonies showed a correlation between the presence of IAPV and colony collapse, triggering a number of additional studies. In this and a future post I’m going to discuss two of these studies.

I’ll note here that correlation is¬†not the same as causation. Perhaps IAPV was detected¬†because the colony was collapsing due to something else? IAPV wasn’t the only thing that correlated with CCD. It’s likely that CCD was a synergistic consequence of some or all of multiple pathogens, pesticides, poor diet, environmental stress, migratory beekeeping, low genetic diversity and the phase of the moon 4.

IAPV

Israeli Acute Paralysis Virus is an RNA virus. That means the genome is made of ribonucleic acid, a different sort of chemical to the deoxyribonucleic acid (DNA) that comprises the genetic material of the host honey bee, or the beekeeper. The relevance of this will hopefully become clear later.

RNA viruses are not unusual. Deformed wing virus (DWV) is also an RNA virus as is Sacbrood virus and Black Queen Cell Virus. In fact, many of the most problematic viruses (for bees or beekeepers [measles, the common cold, influenza, yellow fever, dengue, ebola]) are RNA viruses.

RNA viruses evolve rapidly. They exhibit a number of features that mean they can evade or subvert the immune responses of the host, they can acquire mutations that help them switch from one host to another and they rapidly evolve resistance to antiviral drugs.

To a virologist they are a fascinating group of viruses.

IAPV isn’t a particularly unusual RNA virus. It is a so-called¬†dicistrovirus 5¬†meaning that there are two (di) regions of the genetic material that are expressed (cistrons) as proteins. One region makes the structural proteins that form the virus particle, the other makes the proteins that allow the virus to replicate.

Schematic of the RNA genome of Israeli Acute Paralysis Virus

There are many insect dicistroviruses. These include very close relatives of IAPV that infect bees such as Acute Bee Paralysis Virus (ABPV) and Kashmir Bee Virus (KBV). They are very distant relatives of DWV and, in humans, poliovirus; all belong to the picorna-like viruses (pico meaning small,¬†rna meaning, er, RNA¬†i.e. small RNA containing viruses … I warned you about the Latin).

Phylogenetic relationships between picorna-like viruses

Like DWV, IAPV-infected bees can exhibit symptoms (shivering, paralysis … characteristic of nerve function or neurological impairment in the case of IAPV) or may be asymptomatic. The virus probably usually causes a persistent infection in the honey bee and is transmitted both horizontally and vertically:

  • horizontal transmission – between bees via feeding, direct contact or vector mediated by¬†Varroa (not all of these routes have necessarily been confirmed).
  • vertical transmission – via eggs or sperm to progeny.

IAPV resistance

An interesting feature of IAPV is that some colonies are reported to be resistant to the virus. This is stated in an interesting paper by Eyal Maori 6 but, disappointingly, is not cited.

At the same time these studies were being conducted there was a lot of interest in genetic exchange between pathogens and hosts (e.g. where genetic material from the pathogen gets incorporated into the host) and an increasing awareness of the importance of a process called RNA interference (RNAi) in host resistance to pathogens 7.

Maori and colleagues screened the honey bee genome for the presence of IAPV sequences (i.e. a host-acquired pathogen sequence) using the polymerase chain reaction 8. About 30% of the bees tested contained IAPV sequences derived from the region of the genome that makes the structural proteins of the virus. Other regions of the virus were not detected.

Two additional important observations were made. Firstly, the IAPV sequences appeared to be integrated into a number of location of the DNA of the honey bee (remember IAPV is an RNA virus, so this requires some chemical modifications to be described shortly). Secondly, the IAPV sequences were expressed as RNA. This is significant because RNA is an intermediate in the production of RNAi (with apologies to the biologists who are reading this for the oversimplification and to the non-scientists for some of this gobbledegook. Bear with me.).

And now for the crunch experiment …

Virus challenge

Maori and team injected 300 white eyed honey bee pupae that lacked the integrated IAPV sequence with virus.

Only 2% survived.

They went on to inoculate a further 80 pupae selected at random. Thirteen of these survived (16%) and emerged as healthy-looking adults. The 67 corpses all showed evidence of virus replication and lacked the integrated IAPV sequence in the bee genome.

In contrast, the 13 survivors all contained integrated IAPV sequences but showed no evidence for replication of the virus.

This is of profound importance to our understanding of the resistance of honey bees to pathogens … and in the longer term for the selection or generation of virus-resistant bees.

If it is correct.

Subsequent studies

It’s of such profound importance that it’s extraordinary that there have been no subsequent follow-up papers (at least to my knowledge).

What there have been are number of outstanding but indirectly related studies that have demonstrated a potential mechanism for the integration of RNA sequences into a DNA genome.  We also now have a much improved understanding of how such integrated sequences could confer resistance to the host of the pathogen.

Perhaps the best of these follow-up studies is one by Carla Saleh 9 on the molecular mechanisms that underlie the integration of viral RNA sequences into the host DNA genome. This study also demonstrates how an acute virus infection of insects is converted to a persistent infection.

One of the big problems with the Maori study is explaining¬†how RNA gets integrated. RNA and DNA are chemically similar but different. You can’t just join one to the other.

Saleh showed the an enzyme called an endogenous reverse transcriptase (an enzyme that converts RNA to DNA) was required. In the fruit fly virus model system she worked with she showed that this enzyme was made by a genetic element within the fruit fly genome (hence endogenous) called a retrotransposon.

Importantly, Saleh also showed that the integrated virus sequences acted as the source for interfering RNAs (RNAi) which then suppressed the replication of the virus.

The study by Saleh and colleagues is extremely elegant and explains much of the earlier work on integration of RNA pathogen sequences into the host genome.

However, it leaves a number of questions unanswered about the bits of IAPV that Maori claim are associated with virus resistance in honey bees.

Unfinished business

The Saleh study is really compelling science. Perhaps the same process operates in honey bees?

This is where issues start to appear. The honey bee genome has now been sequenced. Perplexingly (if the Maori study is correct) it contains few transposons and no active retrotransposons.

Without a source of the reverse transcriptase enzyme there’s no way for the RNA to be converted to DNA and integrated into the host genome.

The second major issue is that there are conflicting reports of the presence of viral sequences integrated in the honey bee genome. The assembled sequence 10 appears to contain no virus sequences but there are conference reports of sequences for IAPV, DWV and KBV using a PCR-based method similar to that used by Maori.

Where next?

There’s a lot to like about the Maori study on¬†naturally¬†transgenic bees (a phrase they used in the conclusion to their paper).

It explains the reported IAPV resistance of some bees/colonies (though this needs better documentation). It implicates a molecular mechanism which has subsequently been demonstrated to operate in a number of different insects and host/pathogen systems.

It’s also a result that as a beekeeper and a virologist I’d also like to think offers hope for the future in terms honey bee resistance to the pathogens that can blight our colonies.

Monoculture ... beelicious ...

Monoculture … beelicious …

However, the absence of some key controls in the Maori study, the lack of any real follow-up papers on their really striking observation and the contradictions with some of the genomic studies on honey bees is a problem.

What’s new?

Eyal Maori has a very recent paper (PDF) on RNAi transmission in honey bees. It was in part prompted by the second of the IAPV studies I want to discuss that arose after IAPV was implicated as a possible cause of CCD. That study, to be covered in a future post, demonstrates field-scale analysis of RNAi-based suppression of IAPV.

It is important for two reasons. It shows a potential route to combat virus infections and, indirectly, it emphasises the importance of continuing to properly control Varroa (and hence virus) levels for the foreseeable future.


 

Magic mushrooms not magic bullets

Bees are very newsworthy. Barely a week goes by without the BBC and other news outlets discussing the catastrophic global decline in bee numbers and the impending Beemaggedon.

These articles are usually accompanied by reference to Colony Collapse Disorder (CCD) and the apocryphal quote attributed to Albert Einstein ‚ÄúIf the bee disappears from the surface of the earth, man would have no more than four years to live‚ÄĚ 1.

They also generally illustrate news about honey bees with pictures of bumble bees … and conveniently overlook the global increase in honey bee colonies over the last 50 years.

Never let the truth get in the way of a good story 2

‘shrooms

And the story is particularly newsworthy if it includes the opportunity for a series of entirely predictable (but nevertheless amusing) puns involving mushrooms or fungi 3.

And for me, it is even better if it involves viruses.

It was inevitable I’d therefore finally get round to reading a recent collaborative paper 4¬†from Paul Stamets, Walter Sheppard, Jay Evans and colleagues. Evans is from the USDA-ARS Beltsville bee labs, Sheppard is an entomologist from Washington State University and Stamets is a really fun guy 5, an acknowledged mushroom expert and enthusiast, award-winning author 6 and advocate of mushrooms as a cure for … just about anything. Stamets is the founder and owner of Fungi Perfecti, a company promoting the cultivation of high-quality gourmet and medicinal mushrooms.

An an aside, you can get a good idea of Stamets’ views and all-encompassing passion for ‘shrooms by watching his YouTube video on the¬†Stoned Ape [hypothesis] and Fungal Intelligence.

Fungi and viruses

It has been shown that extracts of fungi can have antiviral activity 7, though the underlying molecular mechanism largely remains a mystery (for a good overview have a look at this recent review in Frontiers in Microbiology¬†by¬†Varpu Marjom√§ki and colleagues). I’m not aware of any commercial antivirals derived from fungi 8 and none that I’m aware of are in clinical trials for human use.

Stamets cites his own observations of honey bees foraging on mycelia (the above-ground fruiting body we call ‘mushrooms’) and speculates that this may be to gain nutritional or medicinal benefit.

Shrooms

Mushroom

This seems entirely reasonable. After all, bees collect tree resins to make propolis, the antimicrobial activity of which may contribute to maintaining the health of the hive.

I’ve not seen bees foraging on fungi, but that certainly doesn’t mean they don’t.

Have you?

Whatever … these observations prompted the authors to investigate whether mushroom extracts had any activity against honey bee viruses.

Not just any viruses

Specifically they tested mushroom extracts against deformed wing virus (DWV) and Lake Sinai Virus (LSV).

DWV is transmitted by Varroa and is globally the most important viral pathogen of honey bees. It probably accounts for the majority of overwintering colony losses due to a reduction in longevity of the fat bodied overwintering bees.

LSV was first identified in 2010 and appears to be widespread, at least in the USA. It has also been detected in Europe and is a distant relative of chronic bee paralysis virus. It has yet to be unequivocally associated with disease in honey bees.

Not just any ‘shrooms

Mycelial extracts were prepared from four species of fungi. As a lapsed fly fisherman I was interested to see that one of those chosen was Fomes fomentarius, the hoof fungus which grows on dead and dying birch trees. This fungus, sliced thinly, is the primary ingredient of Amadou which is used for drying artificial flies 9.

Hoof fungus … and not a honey bee in sight.

Mycelial extract preparation took many weeks and generated a solution of ethanol, aqueous and solvent soluble mycelial compounds together with potentially contaminating unused constituents from the growth substrate. This was administered in thin (i.e. 1:1 w/v) sugar syrup.

Don’t just try hacking a lump off the tree and placing it under the crownboard ūüėČ

Results

In laboratory trials all the fungal extracts reduced the level of DWV or LSV in caged honey bees by statistically significant amounts.

Unfortunately (at least for the layman trying to comprehend the paper) the reductions quoted are n-fold lower, based upon an assay called a quantitative reverse transcription polymerase chain reaction. Phew! It might have been preferable Рother than it being appreciably more work Рto present absolute reductions in the virus levels.

Nevertheless, reductions there were.

Encouragingly they were generally dose-dependent¬†i.e. the more “treatment” added the greater the reduction. A 1% extract of hoof fungus in thin syrup reduced DWV levels by over 800-fold. Against LSV the greatest reductions (~500-fold) were seen with a different extract. In many cases the fold change observed were much more conservative i.e. less activity (though still statistically significant).

A) Normalised DWV and LSV levels in individual bees. B) Activity of mushroom extracts against LSV.

These lab studies encouraged the authors to conduct field trials. Five frame nucleus colonies were fed 3 litres of a 1% solution of one of the two most active extracts. Virus levels were quantified 12 days later. Control colonies were fed thin syrup only.

These field trials were a bit less convincing. Firstly, colonies fed syrup alone exhibited 2- to 80-fold reduction in DWV and LSV levels respectively. Against DWV the fungal mycelial extracts reduced the level of the virus ~40-fold and ~80-fold better than syrup alone. LSV levels were more dramatically reduced by any of the treatments tested; ~80-fold by syrup alone and ~90-fold or ~45,000-fold better than the syrup control by the two mycelial extracts.

Or is it any ‘shrooms … or ‘shrooms at all?

It’s worth emphasising that syrup-alone is¬†not the correct control for use in these studies. As stated earlier the mycelial extract likely also contained constituents from the fungal growth media (sterilised birch sawdust).

The authors were aware of this and also tested extracts prepared from uninoculated birch sawdust. This definitely contained endogenous fungal contamination as they identified nucleic acid from ‘multiple species’ of fungi in the sterilised sawdust, the majority from three commonly birch-associated fungi (none of which were the original four species tested).

The authors are a little coy about the effect this birch sawdust extract had on virus levels other than to say¬†“extracts from non-inoculated fungal growth substrate also showed some activity¬†against DWV and LSV”. In lab studies it appears as though ‘some activity’ is between 8- and 120-fold reduction.

Without some additional controls I don’t think we can be certain that the compound(s) responsible for reducing the viral levels is even derived from the mushroom mycelium, whether the endogenous ones present in the sawdust, or those grown on the sawdust.

For example, perhaps the active compound is a constituent of birch sawdust that leaches out at low levels (e.g. during the extraction process) but that is a released in large amounts when fungi grow on the substrate?

Hope or hype?

Readers with good memories may recollect articles from fifteen years ago about fungi with activity against¬†Varroa. In that case the fungus was Metarhizium anisopliae. There are still groups working on this type of biological control for mites but it’s probably fair to say that¬†Metarhizium has not lived up to its early promise 10.

A lot more work is needed before we’ll know whether mushroom extracts have any specific activity against honey bee viruses. There are lots of unanswered questions and it will take years to have a commercial product for use by beekeepers.

Don’t get rid of your stocks of oxalic acid or Apivar yet!

Questions

What are the active ingredient(s) and mode of action?

Do the extracts actually have any activity against the viruses per se, or do they instead boost the immune response of the bee and make it better to resist infection or clear established infections?

How specific are the extracts? Do they have activity against other RNA viruses of honey bees? What about¬†Nosema? Or the foulbroods? If they boost immune responses you’d expect a broad range of activities against bee pathogens.

You’d also expect that bees would have evolved to actively forage on mushroom fruiting bodies and so be a common sight in late summer/early autumn.

Are they toxic to bees in the longer term? Are they toxic for humans?¬†Fomes formentarius is considered “inedible, with a slightly fruity smell and acrid taste”. Delicious!

Finally, is the reduction in virus levels observed in field studies sufficient to have a measurable positive influence on colony health? It’s worth remembering that Apivar treatment reduces mite levels by 95% and virus levels by about 99.9999%.


Colophon

Magic!

Magic mushroom is a generic term used to refer to a¬†polyphyletic group of fungi that contain any of various psychedelic compounds, including psilocybin, psilocin, and baeocystin. Talk to Frank to find out more about the effects and dangers of magic mushrooms. The de facto¬†standard guide for the identification of magic mushrooms is Psilocybin Mushrooms of the World by … you guessed it, Paul Stamets.

The term magic mushroom was first used in Life magazine in 1957.

A magic bullet is a highly specific drug or compound which kills a microbial pathogen without harming the host organism. The term (in German, Zauberkugel) was first used by Nobel laureate Paul Ehrlich in 1900. Ehrlich discovered/developed the first magic bullet, Salvarsan or Arsphenamine, an organoarsenic compound that is effective in the treatment of syphilis.

Mycelial extracts of fungi are not (yet at least) a magic bullet for use in the control of honey bee viruses.

BOGOF

The swarm season this year has been atypical. At least here in the coolish, dampish, East coast of Scotland.

I hived my first swarm of the year on the last day of April and – as I write this – my most recent one in the middle of July.

The intervening period has been pretty quiet as the weather in May and June was – after a warm early spring – rather poor 1. The weather picked up a week or so ago, but it’s not been consistently good.

What we have had recently are some very warm and sunny days. The combination of some iffy weather, a bit of nectar coming in and then a few hot days are great conditions to trigger swarming.

Bait hives

For this reason I keep bait hives in my apiaries and one in my back garden throughout the season. These consist of a brood box with a solid floor, one old black frame anointed with lemongrass oil on the top bar, ten foundationless frames, a plastic crownboard and a roof of some sort.

Bait hive ...

Bait hive …

Any interest in these by scout bees suggests that there’s a colony nearby thinking of swarming. Scouts clearly check out potential locations¬†before the colony swarms, but the scout activity increases significantly if they find your offering attractive and once the colony swarms and sets up a temporary bivouac from which it subsequently relocates.

Watching scout bee numbers increase allows you to guesstimate when a swarm might arrive. It’s an inexact science. A few scout bees are nothing to get excited about. Dozens are good and a hundred or two are very promising.

However, what’s best of all are a hundred or so scouts that rather suddenly¬†disappear leaving the bait hive suspiciously quiet.

Which is more or less what happened on Sunday at the bait hive in my garden.

Walking wounded

Scout bees had discovered the bait hive sometime on Friday (or at least, this was when I first noticed them).

The weekend started warm with thunder threatened. I finished my colony inspections and returned for lunch to find a couple of dozen scouts checking out the bait hive 2. As the cloudy and muggy conditions continued scout bee numbers increased during the afternoon and then eventually tailed off as the evening cooled.

Sunday dawned warm and bright. Scouts were up and about before I’d made my first mug of coffee at 7 am. Numbers increased significantly during the morning.

While taking a few photos for talks I noticed a handful of corpses and walking wounded bees crawling around on the ground by the bait hive.

Missing in action

On closer inspection it was clear that there were intermittent fights between scouts at the hive entrance. There were more fights than cripples or corpses, and most fights ended with the scrapping bees breaking apart and continuing to, er, scout out the suitability of the bait hive.

Scout bees fighting from The Apiarist on Vimeo.

This behaviour seemed a bit unusual, but there wasn’t an obvious explanation for it. I wondered if I’d inadvertently used a frame with some stores tucked away in the top corners, with the fighting being between scouts and robbers perhaps 3.

Gone but not forgotten

Scout numbers continued to increase …

The calm before the storm

By Sunday lunchtime I was confidently predicting a swarm would be arriving ‘shortly’.

This prediction was upgraded to ‘very shortly’ once I realised – around 3 pm – that the scout bee activity had suddenly dwindled to just a few.

This happens when the scouts assemble en masse and persuade the bivouacked swarm to take flight and relocate. Honeybee Democracy by Thomas Seeley has a full explanation of this fascinating behaviour.

And, sure enough, ten minutes later a swirling maelstrom of bees approached purposefully down the street at chimney height, spiralling down to the bait hive.

You hear it first. Is it? Isn’t it? You look up and around. You can’t place the direction the noise is coming from. Then, at walking pace, they appear.

Hundreds, then thousands, milling around, getting lower, festooning the hive front, landing all around, taking flight and settling again.

Incoming! from The Apiarist on Vimeo.

At the hive entrance are hundreds of bees fanning frantically. The queen must have already entered the box. Slowly, over an hour or so, the bees settle, enter the box and just leave a few stragglers around the entrance.

One hour later from The Apiarist on Vimeo.

Swarms are a fantastic sight in their own right. They’re even better when you have some insights into how ten thousand individuals with a brain the size of a pin head are corralled and coordinated to rehouse the queen, the flying workers and a few dozen drones that are ‘along for the ride’.

Again, I cannot recommend Honeybee Democracy highly enough as a very accessible guide to swarms and swarming.

Late evening, another move

The evening slowly cools. I can’t resist gently hefting the box to guesstimate the size of the swarm. Small to middling perhaps … a view pretty-much confirmed when I peek under the roof to see about 5-6 seams of bees occupying the back of the box.

We have a new puppy and it was clear (i.e. I was told in no uncertain terms) that the occupied bait hive must be moved to a less accessible spot.

I plug the entrance with some tissue and gently carry them around to a puppy-free location on the other side of the house.

Swarms suffer short-term geographic memory loss. They can be moved any distance you want for the first day or two after hiving them. After that they’ll have reorientated to the new location and the standard 3 feet/3 miles rule applies (which isn’t a rule at all).

Early morning, more activity

Monday dawned calm, warm and bright.

It was clearly going to be a fabulous day.

One of the great things about being an academic is the flexibility you have once the students have disappeared to Ibiza or Machu Picchu or wherever for the summer 4.

I was therefore looking forward to a day of¬†wall-to-wall meetings, at least 3 hours of which would be in a basement room with no windows ūüôĀ

At 7:30 am I checked the relocated and occupied bait hive. All good. Almost no entrance activity but a contented gentle buzzing from inside suggested that all was well.

As I left the house I noticed a dozen or so bees milling around the stand where the bait hive had originally been located.

Puppy territory. Oops!

I quickly dumped a floor, a brood box with half a dozen frames and a roof on the stand in the hope that any stragglers from the swarm – which I suspected were scouts that had got lost, or workers that had already reorientated to the occupied bait hive late the previous afternoon – would settle (or clear off).

No signal

Having been trapped underground in an overrunning meeting on the hottest day of the year I missed the following messages that all appeared in a rush when my phone reconnected on surfacing.

11:55 Lots of bees

13:27¬†Even more¬†bees. I thought you’d moved them last night?

15:06 Bl%^dy hundreds of bees. Where are you?

16:11 HUGE swarm

As I blinked myopically in the bright sunlight, like a lost mole, I realised what I’d seen yesterday were scouts from two separate colonies fighting at the bait hive entrance.

The bees I’d seen the following morning had been scouts from the second swarm.

Another day, another bait hive, another swarm …

Which had now arrived.

Overestimates and underestimates

As a beekeeper I’m well aware that a puppy-protecting non-beekeeper telling me about¬†Lots of bees and¬†Even more bees probably means¬†Some bees.

The term¬†‘hundreds’ might mean any number less than 100.

It’s worth noting here that the partner of a non-beekeeper is considerably more accurate than the general public. If I get a message from someone with no experience of beekeeping about¬†‘hundreds of honey bees.¬†Definitely honey bees!’ I know what they’re actually talking about are 12-15 solitary bees … probably¬†Osmia.

Or wasps.

HUGE is tricky though. It has a sort of indefinable unmeasurable quality of largeness about it.

Thousands would have been easy … a small cast perhaps?

But¬†HUGE … ?

It was huge.

Certainly the biggest swarm I’ve seen in recent years ūüôā

I had to open the box to add a full complement of frames. The poly hive was heavy. You could feel the swaying mass of bees hanging from the wooden crownboard over the empty space in the box 5. The few frames present were completely covered.

I bumped the bees off the crownboard, lifted it away and the bees formed a very deep layer at the bottom of the brood box 6. The new foundationless frames I added projected well above the frame runners supported by the writhing mass of bees and only gently settled into place as the bees moved out of the way and up the sidewalls.

I strapped the box up and moved it to a puppy-safe location.

The following evening I treated both swarms with a vaporised oxalic acid-containing miticide and the morning after that I shifted them to an out apiary.

Look and learn

Only last week I discussed the importance of learning from observation.

Here was another lesson.

What did I learn from these two swarms and what assumptions can I make?

  1. Evidence of fighting between scout bees¬†strongly suggests that there are two different swarms looking for a new home. I’m making the assumption here 7 that the two swarms issued from¬†different hives (rather than being two casts from the same hive 8) because:
    1. I wouldn’t expect scouts from the¬†same hive to fight, even if they were from different swarms. Is this actually known?
    2. I’m told¬†the two swarms approached the bait hive from opposite directions (I saw the first one of course, but not the¬†millions of bees in a¬†huge swarm that arrived the following day when I was – literally – buried in meetings).
  2. Scouts are active well before a hive gets busy in the morning – at least one containing a recently hived swarm. I’ve noticed this before. Perhaps the recently hived swarm is concentrating on drawing comb as a priority?
  3. It is important to have sufficient spare compatible equipment available for all sorts of eventualities. I got away with it this time … just. The first bait hive used a planting tray as a lid. The second used some spare bits kicking around in the back of the car and a handful of foundationless frames just out of the steamer.
  4. I must remember to save time after the swarm arrives by preparing the bait hive properly in advance. This includes giving it a full complement of foundationless frames (and the one dark frame) and Рif you intend to move it any distance after swarm arrival Рmaking it ready for transport. In my case this includes using an insect mesh travel screen instead of a crownboard, adding a foam wedge to stop frames shifting about during transport and strapping the whole lot up tight.
Foam block ...

Foam block …

Natural cavities

The whole purpose of putting out bait hives is to attract swarms. As a beekeeper this saves me collecting them from the neighbourhood or – more frequently – politely refusing to collect them from 40′ up a Leylandii, a chimney or the church tower 9.

If something is worth doing you might as well do it properly. The optimal design for a bait hive is well understood (essentially it’s a National hive brood box – Honeybee Democracy¬†again!), so that’s what I offer. Not a nuc 10.

However, to have two swarms essentially fighting for access to a single bait hive suggests there is a shortage of good natural or man-made cavities to which a swarm could relocate.

I live in a small village surrounded by mainly arable farmland. There are lots of hedges, small spinneys, conifer plantations, old farm buildings and houses about 11.

Rather too much arable if you ask me …

I’ve got a fair idea where bees are kept locally. I don’t think there are any within a mile of the bait hive other than my own colonies (and they did not swarm).

I would have expected there to be several suitable local natural or man made cavities that could ‘compete’ with a bait hive to attract swarms.

Clearly not … or they are already all occupied 12.

STOP PRESS Both were prime swarms as they had laying queens when I checked them on Thursday afternoon. I should have also added that a bait hive in the same location attracted another swarm in the preceding week. It’s been a successful spot¬†every year I’ve been back in Scotland.


Colophon

Buy one, get one free (BOGOF) seemed an appropriate title for this post. It dates back to 1985 where it was first used in the journal Progressive Grocer (who knew there was such a thing?). Two for the price of one offers have been blamed for spiralling obesity problems and there has been political pressure to ban such offers in supermarkets.

In draft form this post was entitled twofer. As in two for the price of one. Etymologically this is an older term, but surprisingly the OED does not associate it with cricket.

Twofer is regularly used by cricket pundits to mean two wickets in successive balls. However, I decided to avoid the cricket link so as to not upset any of my valued New Zealand readers who might still be smarting from the double-whammy of a cricket World Cup defeat to England and losing the claim to have the World’s steepest street to Wales.

My commiserations ūüėČ

Teaching in the bee shed

An observant beekeeper never stops learning. How the colony responds to changes in forage and weather, how swarm preparations are made, how the colony regulates the local environment of the hive etc.

Sometimes the learning is simple reinforcement of things you should know anyway.

Or knew, but forgot. Possibly more than once.

If you forget the dummy board they¬†will build brace comb in the gap ūüôĀ

There’s nothing wrong with learning by reinforcement though some beekeepers never seem to get the message that knocking back swarm cells¬†is not an effective method of swarm control ūüėČ

Learning from bees and beekeeping

More generally, bees (and their management) make a very good subject for education purposes. Depending upon the level taught they provide practical examples for:

  • Biology – (almost too numerous to mention) pollination, caste structure, the superorganism, disease and disease management, behaviour
  • Chemistry – pheromones, sugars, fermentation, forensic analysis
  • Geography and communication – the waggle dance, land use, agriculture
  • Economics – division of labour (so much more interesting than Adam Smith and pin making), international trade
  • Engineering and/or woodwork – bee space, hive construction, comb building, the catenary arch

There are of course numerous other examples, not forgetting actual vocational training in beekeeping.

This is offered by the¬†Scottish Qualifications Authority in a level 5 National Progression Award in Beekeeping¬†and I’ve received some enquiries recently about using a bee shed for teaching beekeeping.

Shed life

For our research we’ve built and used two large sheds to accommodate 5 to 7 colonies. The primary reason for housing colonies in a shed is to provide some protection to the bees and the beekeeper/scientist when harvesting brood for experiments.

On a balmy summer day there’s no need for this protection … the colonies are foraging strongly, well behaved and good tempered.

But in mid-March or mid-November, on a cool, breezy day with continuous light rain it’s pretty grim working with colonies outdoors. Similarly – like yesterday – intermittent thunderstorms and heavy rain are not good conditions to be hunched over a strong colony searching for a suitable patch containing 200 two day old larvae.

Despite the soaking you get the colonies are still very exposed and you risk chilling brood … to say nothing of the effect it has on their temper.

Or yours.

Bee shed inspections

Here’s a photo from late yesterday afternoon while I worked with three colonies in the bee shed. The Met Office had issued “yellow warnings” of thunderstorms and slow moving heavy rain showers that were predicted to drift in from the coast all afternoon.

All of which was surprisingly accurate.

Bee shed inspections in the rain

For a research facility this is a great setup. The adverse weather doesn’t seem to affect the colonies to anything like the same degree as those exposed to the elements. Here’s a queenless colony opened minutes before the photo above was taken …

Open colony in the bee shed

Inside the shed the bees were calmly going about their business. I could spend time on each frame and wasn’t bombarded with angry bees irritated that the rain was pouring in through their roof.

Even an inexperienced or nervous beekeeper would have felt unthreatened, despite the poor conditions outside.

So surely this would be an ideal environment to teach some of the practical skills of beekeeping?

Seeing and understanding

Practical beekeeping involves a lot of observation.

Is the queen present? Is there brood in all stages? Are there signs of disease?

All of these things need both good eyesight and good illumination. The former is generally an attribute of the young but can be corrected or augmented in the old.

But even 20:20 vision is of little use if there is not enough light to see by.

The current bee shed is 16′ x 8′. It is illuminated by the equivalent of seven 120W bulbs, one situated ‘over the shoulder’ of a beekeeper inspecting each of the seven hives.

On a bright day the contrast with the light coming in through the windows makes it difficult to see eggs. On a dull day the bulbs only provide sufficient light to see eggs in freshly drawn comb. In older or used frames – at least with my not-so-young eyesight – it usually involves a trip to the door of the shed (unless it is raining).

It may be possible to increase the artificial lighting using LED panels but whether this would be sufficient (or affordable) is unclear.

Access

Observation also requires access. The layout of my bee shed has the hives in a row along one wall. The frames are all arranged ‘warm way’ and the hives are easily worked from behind.

Hives in the bee shed

Inevitably this means that the best view is from directly behind the hive. If the shed was used as a training/teaching environment there’s no opportunity to stand beside the hive (as you would around a colony in a field), so necessitating the circulation of students within a rather limited space to get a better view.

A wider shed would improve things, but it’s still far from ideal and I think it would be impractical for groups of any size.

And remember, you’re periodically walking to and from the door with frames …

Kippered

If you refer back to the first photograph in this post you can see a smoker standing right outside the door of the shed.

If you use or need a smoker to inspect the colonies (and I appreciate this isn’t always necessary, or that there are alternative solutions) then it doesn’t take long to realise that the smoker must be kept¬†outside the shed.

Even with the door open air circulation is limited and the shed quickly fills with smoke.

If you’ve mastered the art of lighting a properly fuelled efficient smoker the wisp of smoke curling gently up from the nozzle soon reduces visibility and nearly asphyxiates those in the shed.

Which brings us back to access again.

Inspections involve shuttling to and from the door with frames or the smoker, all of which is more difficult if the shed is full of students.

Or bees … which is why the queen excluder is standing outside the shed as well. I usually remove this, check it for the queen and then stand it outside out of the way.

Broiled

In mid-March or November the shed is a great place to work. The sheltered environment consistently keeps the temperature a little above ambient.

Colonies seem to develop sooner and rear brood later into the autumn 1.

But in direct sunlight the shed can rapidly become unbearably warm.

Phew!

All the hives have open mesh floors and I’ve not had any problems with colonies being unable to properly regulate their temperature.

The same cannot be said of the beekeeper.

Working for any period at temperatures in the low thirties (Centigrade) is unpleasant. Under these conditions the shed singularly fails to keep the beekeeper dry … though it’s sweat not rain that accumulates in my boots on days like this.

Bee shelters

For one or two users a bee shed makes a lot of sense if you:

  • live in an area with high rainfall (or that is very windy and exposed) and/or conditions where hives would benefit from protection in winter
  • need to inspect or work with colonies at fixed times and days
  • want the convenience of equipment storage, space for grafting and somewhere quiet to sit listening to the combined hum of the bees in the hives and¬†Test Match Special ūüėČ

But for teaching groups of students there may be better solutions.

In continental Europe 2 bee houses and bee shelters are far more common than they are in the UK.

I’ve previously posted a couple of articles on German bee houses – both basic and deluxe. The former include a range of simple shelters, open on one or more sides.

A bee shelter

Something more like this, with fewer hives allowing access on three sides and a roof – perhaps glazed or corrugated clear sheeting to maximise the light – to keep the rain off, might provide many of the benefits of a bee shed with few of the drawbacks.


 

Droning on

This post was supposed to be about¬†Varroa resistance in¬†Apis mellifera – to follow the somewhat controversial ‘Leave and let die’ from a fortnight ago. However, pesky work commitments have prevented me doing it justice so it will have to wait for a future date.

All work and no play …

Instead I’m going to pose some questions (and provide some partial answers) on overwintering mites and the use of drone brood culling to help minimise mite levels early in the season.

Imagine the scenario

A poorly managed colony goes into the winter with very high mite levels. Let’s assume the beekeeper failed to apply a late summer/early autumn treatment early enough and then ignored the advice to treat again in midwinter when the colony is broodless.

Tut, tut …

The queen is laying fewer and fewer eggs as the days shorten and the temperature drops. There are decreasing amounts of the critical 5th instar larvae that the mite must infest to reproduce.

At some point the colony may actually be broodless.

What happens to the mites?

Do they just hang around as phoretic mites waiting for the queen to start laying again?

Presumably, because there is nowhere else they can go … but …

What about the need for nurses?

During the Varroa reproductive cycle newly emerged mites preferentially associate with nurse bees for ~6 days (usually quoted as 4-11 days) before infesting a new 5th instar larva.

Mites that associate with newly emerged bees or bees older than nurse bees exhibit reduced fecundity and fitness i.e. they produce fewer progeny and fewer mature progeny 1 per infested cell.

I’m not aware of studies showing the influence of the physiologically-distinct winter bees on mite fecundity.

Similarly, I’m not sure if there are any studies that have looked at the types of bees phoretic mites associate with during the winter 2, or the numbers of bees in the colony during November to January 3 that might be considered to be similar physiologically to nurse bees.

Whilst we (or at least I) don’t know the answer to these questions, I’m willing to bet – for reasons to be elaborated upon below – that during the winter the fecundity and fitness of mites decreases significantly.

And the number of the little blighters …

Mite longevity

How long does a mite live?

The usual figure quoted for adult female mites is 2-3 reproductive cycles (of ~17 days and ~11 days for the first and subsequent rounds respectively). So perhaps about 40 days in total.

But, in the absence of brood (or if brood is in very short supply) this is probably longer as there is data linking longevity to the number of completed reproductive cycles i.e. if there is no reproduction the mite can live longer.

It is therefore perhaps reasonable to assume that mites should be able to survive through a broodless period of several weeks during midwinter. However, remember that this increases the chance the mite will be removed by grooming or other physical contacts within the cluster, so reducing the overall population.

Spring has sprung

So, going back to the scenario we started with …

What happens in late winter/early spring when the queen starts laying again?

Does that 5cm patch of early worker brood get immediately inundated with hundreds of mites?

If so, the consequences for the early brood are dire. High levels of mite infestation inevitably mean exposure to a large amount of deformed wing virus (DWV) which likely will result in precisely the developmental deformities you’d expect … DWV really “does what it says on the tin”.

Worker bee with DWV symptoms

Worker bee with DWV symptoms

My hives are carefully managed to minimise mite levels. I don’t really have any personal experience to help answer the question. However, in colonies that have higher (or even high) mite levels I don’t think it’s usual to see significant numbers of damaged bees in the very earliest possible inspections of the season 4.

My (un)informed guess …

My guess is that several things probably happen to effectively reduce exposure of this earliest brood to Varroa:

  1. Varroa levels in the colony drop due to the extended winter phoretic phase. More opportunities for grooming or similar physical contact (perhaps even clustering) increase the loss of mites.
  2. Mites that remain may have reduced access to brood simply due to the mathematical chance of the bee they are phoretic on coming into contact with the very small numbers of late stage larvae in the colony.
  3. Mites that do infest brood have reduced fecundity and fitness and may not rear (m)any progeny.

There are a lot of assumptions and guesswork there. Some of these things may be known but discussions I’ve had with some of the leading¬†Varroa researchers suggest that there are still big gaps in our knowledge.

OK, enough droning on, what about drones?

Back to the imagined scenario.

What happens next?

Well, perhaps not next, but soon?

The colony continues to contract (because the daily loss of aged workers still outnumbers the daily gain of new bees) but the laying rate of the queen gradually increases from a few tens, to hundreds to a couple of thousand eggs per day.

And the colony starts to really expand.

And so do the mite numbers …

Pupa (blue) and mite (red) numbers

And at some point, depending upon the expansion rate, the climate and (probably) a host of factors I’ve not thought of or are not known, the colony begins to make early swarm preparations by starting to rear drones.

Drones take 24 days to develop from the egg and a further 12-16 days to reach sexual maturity. If the swarming period starts in the first fortnight of May, the drones that take part were laid as eggs in late March.

And drone larvae are very attractive to Varroa.

9 out of 10 mites prefer drones

Varroa replicates ‘better’ in association with drone pupae. By better I mean that more progeny are produced from each infested cell. This is because the drone replication cycle is longer than that of worker brood.

The replication cycle of Varroa

The replication cycle of Varroa

On average 2.2 new mites are produced in drone cells¬†vs only 1.3 in worker cells 5. From an evolutionary standpoint this is a significant selective pressure and it’s therefore unsurprising that Varroa have evolved to preferentially infest drone brood.

Irrespective of the mite levels, given the choice between worker and drone, Varroa will infest drone brood at 8-11 times the level of worker brood 6.

Significantly, as the amount of drone brood was reduced (typically it’s 5-15% of comb in the hive) the¬†drone cell preference increased by ~50% 7.

I hope you can see where this is now going …

Early drone brood sacrifice

As colony expansion segues into swarm preparation the queen lays small amounts of drone brood. These cells are a very small proportion of the overall brood in the colony but are disproportionately favoured by the mite population.

And the mite population – even in a poorly managed colony – should be less (and less fit) in the Spring than the preceding autumn for reasons elaborated upon above (with the caveat that some of that was informed guesswork).

Therefore, if you make sure you remove the earliest capped drone brood you should also remove a significant proportion of the viable mites in the colony.

Drone brood is usually around the periphery of the brood nest, along the bottom of frames with normal worker foundation, or on the ‘shoulders’ near the lugs. The drone brood is often scattered around the brood nest.

As a consequence, if you want to remove all the earliest capped drone brood you have to rummage through the frames and ‘fork out’ 8 little patches here and there.

It can be a bit of a mess.

Is there an easier way to do this?

Drone cells

Beekeepers who predominantly use foundationless frames will be aware that they usually have significantly more drones (and drone comb) in their colonies than equivalent sized colonies using embossed worker foundation.

Depending upon the type of foundationless frames used the drone comb is drawn out in different positions on the frames.

Horizontally wired foundationless frames can be all drone brood or a mix of drone and worker. However, the demarcation between the brood types is often inconveniently located with regard to support wires.

In contrast, foundationless frames constructed using vertical¬†bamboo supports are often built as ‘panels’ consisting entirely of drone¬†or worker comb.

Drone-worker-drone

Drone-worker-drone …

Which makes slicing out one or more complete panels of recently capped drone brood simplicity itself.

There are no wires in the way.

You can sometimes simply pull it off the starter strip.

Drone brood sacrifice

Check the brood for Varroa 9, feed the pupae to your chickens and/or melt out the wax in your steam wax extractor.

The bees will rapidly rebuild the comb and will not miss a few hundred drones.

They’ll be much healthier without the mites. Importantly, the mites will have been removed from the colony¬†early in the season so preventing them going through repeated rounds of reproduction.

This is the final part of the ‘midseason mite management‘ triptych 10, but I might return to the subject with some more thoughts in the future … for example, continuous culling of drone brood (in contrast to selective culling of the very earliest drone brood in the colony discussed here) is not a particularly effective way of suppressing mite levels in a colony.


 

 

 

 

 

Off again, on again …

The title of this post could refer to the 2019 season, queen mating, forage availability and the honey supers.

And does …

All are, of course, related to the local weather.

This is my fourth year back in Scotland keeping bees and the season started really well. Scout bees were examining my bait hives by late April and I hived my first swarm on the last day of that month.

Fanning bees

Fanning bees

April had been a good month and overwintered colonies were consequently in pretty good shape and had built up well to (hopefully) exploit the early season forage. Overwintered nucs looked particularly strong …

Here's one I prepared earlier

Here’s one I prepared earlier

The oil seed rape (OSR) appeared as expected – there’s quite a bit in range of both my main apiaries – and the bees started hammering it.

And then the weather reverted to ‘about average’ … which for my part of eastern Scotland in May is a mean maximum daily temperature of 12-14¬įC. With these lower temperatures came higher than average rainfall.

Nothing dramatic, but enough to – literally – put the dampeners on the first half of the season.

June gap

May segued into June and the OSR came and went. Work commitments kept me away from the apiary which meant the clearers went on about a week later than intended.

Unfortunately this was a week in which the weather deteriorated and strong colonies were stuck ‘indoors’ where they had little to do but scoff the stores. And when they could get out there was a shortage of forage – we’ve had a proper ‘June gap‘ this year 1.

Nevertheless, after extracting I managed just shy of 50% of the total from last spring (which was an exceptional year) so I’m not complaining.

One thing notable about this season was that the majority of the supers extracted were not fully capped. Some weren’t capped at all. I’d left a few ‘drippy’ supers behind and every frame extracted passed the ‘shake test’.

(Very) partially capped honey super frame ...

(Very) partially capped honey super frame …

After extraction¬†I always check the water content of every bucket and it was all in the 16-17.5% region … no different from capped spring honey extracted in previous years.

Wheely good extraction

I’ve finally got round to mounting my SAF Natura 9 frame radial extractor on castors 2. I re-drilled the end of the three legs to accept an M10 bolt and then fitted castors with a couple of nuts, one of which was nylon-lined so it should not work loose.

Rubber-wheeled castor with brake

Two of the castors are braked, but they don’t need to be.

The castors make it a lot easier to move the extractor from storage to my extracting room 3 or to the area where I hose it out after use.

No more jiggling

But much more significantly (and the reason I fitted them in the first place) they prevent a poorly balanced extractor from ‘walking’ across the room if unbalanced and unattended.

I no longer have to cling on for dear life until the machine stops jiggling about ūüôā

Of course, I always try and balance my extractor. However, the reality is that you sometimes get frames with crystallised honey which unbalance the extractor late in the run. Or runs in which no amount of juggling of the frames achieves a really satisfactory balance.

Under these circumstances the wheels allow the unbalanced extractor to oscillate from side to side rather than march off down the room.

Adding the little rubber wheels has been a¬†revolution¬†in my extracting if you’ll excuse the lousy pun.

… and away again

Summer has now officially started as the longest day has – like the OSR – been and gone. Today we’ve had rain, thunder and lightning¬†i.e. ¬†a typical summer day and almost perfect conditions to return a towering stack of wet supers to the hives.

The bees were not impressed to be disturbed 4 but were grateful for the wet supers. By dealing with these in the late afternoon on a manky day I avoided the bees getting overexcited and triggering robbing.

It’s clear that the June gap is, if not over then certainly drawing to a close. All colonies have fresh nectar stored in the brood frames and the supers in strong colonies are starting to get heavier.

The rain might even help get a good crop from the lime this year (it was far too dry last season) but we need high temperatures as well.

With a bit of good fortune we’ll also now get some good enough weather for queen mating which has been really hit and miss for the last month.

Where did they come from?

Clearly there are some queens getting reared.

I was called out to a swarm in a neighbours garden late in the afternoon a few days ago. It had been in a low bush for a few hours and was a doddle to drop into a Paynes poly nuc. I’ve yet to see the queen so don’t know whether she’s mated or marked.

What’s puzzling is where the bees swarmed from …

My understanding is that the classic football-sized ball of bees hanging from a branch is a temporary bivouac. The swarm sets up camp there while the scouts do their scouting around looking for a better location to make a permanent residence.

Swarm of bees

Swarm of bees

In my experience the bivouacked bees are usually only a short distance from their original location. By¬†‘short distance’ I mean 5 to 50 metres. Perhaps 100 at the outside. You don’t just find them randomly dotted around the countryside 5.

Which is what’s odd … the closest apiary to the swarm is mine (perhaps 500 metres away). I’d inspected my colonies the same afternoon. All the queens were present and correct. All are marked and clipped. None of the colonies showed any sign of wanting to swarm 6. It’s definitely not from my colonies.

My village is very small. I don’t know everyone but I know someone who does. There are no other beekeepers here. So where did they come from?

Perhaps they were a swarm from a distant colony that failed to reach their intended destination (like one of my bait hives which had been getting some attention 7). Alternatively they might come from a nearby feral colony.

I’m off to take a closer look at the church tower …


Colophon

The title of this post is truncated from the start of the chorus of a 1921 song by E.R. Edson about a train conductor (Flanagan) and a derailed train …¬†“Off again, on again, gone again, Flanagan”.