Category Archives: Practice

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.

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.


 

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

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”.

Window of opportunity

I’ve recently discussed problems faced by beekeepers trying to control high Varroa¬†levels in colonies during the ‘body’¬†of the beekeeping season.¬†Essentially the problems are two-fold:

  • Many miticides need to be used for several weeks to target mites in capped cells.
  • The soft or hard chemicals used for¬†Varroa control are – with the exception of the formic acid in MAQS – incompatible with honey production.

This type of midseason mite management should not be needed if parasite levels are controlled in late summer and midwinter.

If it is needed it suggests that the treatment(s) failed or that mites are being acquired through robbing or drifting from other colonies in the neighbourhood (either your own, a nearby apiary or a feral colony).

Opportunity knocks

However, all is not lost. Most seasons offer at least one opportunity to intervene and control mite levels.

Knowing when and how to exploit it requires an appreciation of the development cycle of the bee.

Honey bee development

Honey bee development

The important numbers are the 21 and 24 day development cycle of workers and drones respectively, the 16 day development cycle of the queen and the time it takes for eggs to hatch, grow as larvae and pupate in capped cells.

Not shown is the maturation period after emergence for the queen (5 to 6 days) before she goes on a mating flight, or the delay after returning before she starts laying (2-3 days) 1.

Swarms

The easiest scenario to discuss is when the colony swarms.

Consider the swarm first. A prime swarm is broodless, contains a mated queen and ~35% of the mites that were present in the issuing colony. All the mites will be phoretic. Assuming there’s drawn comb available the queen will start laying soon after the swarm is hived (or conveniently moves into your bait hive).

Eight days later the first eggs will have hatched, the larvae grown and the brood will be capped.

At which point the majority of the mites will start to become inaccessible again.

However, during those 8 days it’s ‘open season’ for those phoretic mites.

It is sensible to quarantine swarms from an unknown source and treat for mites in the first 8 days if needed.

If the swarm is a cast with an unmated queen you’ve got a bit more time. The virgin queen needs to get out and mate, mature and start laying. This tends to happen in just a few days if the weather is accommodating, so don’t leave things too long.

The swarmed colony

Now consider what’s left in the colony that swarmed 2. There will be sealed and unsealed brood and – notwithstanding the reduced egg laying by the queen as she’s slimmed down in preparation for swarming – there are also likely to be some eggs.

There will also be a sealed queen cell (and, in a strong colony, several sealed and unsealed queen cells).

Queen cells ...

Queen cells …

Without intervention the queen(s) will start emerging about 9 days later. If you intervene, knocking down all the sealed cells and leaving just one good charged open cell 3, it will be a couple more days before the queen emerges.

Weather permitting it will be a further 8 days before the newly mated queen starts laying. In reality, this is the absolute minimum and is rarely achieved in a full hive 4.

Simultaneously, in the requeening hive, the open brood is maturing and being capped and the capped brood is emerging (releasing more mites).

About eight days after the swarm leaves all the worker brood in the hive will be capped.

Twenty one (or 24 in the case of drone brood) days after the last egg was laid by the queen all the brood will have emerged.

Consequently all the mites in the colony will be phoretic.

The window of opportunity

So, if you need to treat 5 the window of opportunity is between the last of the brood from the old queen emerging and the first of the larvae from the new queen being capped.

You can determine when this is likely to be based upon the known activities of the old and new queen during the swarming period.

The window of opportunity

The diagram above makes a number of assumptions. As presented, all minimise the duration of the minimum broodless period:

  • The old queen continues laying until the day she swarms
  • The colony swarms on the day the queen cell is sealed
  • The beekeeper does not intervene to leave an open, charged cell of a known age
  • The new queen takes the minimum amount of time to mature, go on a mating flight and start laying

It should be self-evident that more realistic timings applied to these will only increase the length of the minimum broodless period.

For example, the weather will have a significant impact. Swarming may be delayed due to adverse conditions. During this time the slimmed-down queen will probably lay very few eggs.

Similarly, only 8 days are shown for maturing, mating and starting to lay. Mating flights are very weather-dependent and this period could easily take a week longer (or more).

Splits and artificial swarms

If you practice swarm control using the nucleus method, vertical splits or the classic Pagden artificial swarm the same types of calculations apply.

These three methods all share two features:

  • They involve the physical separation of the box with the old queen and the new developing queen
  • The old queen is isolated with a very small amount of brood – either open brood or emerging brood

The queenright component of the split (whether nuc box or new brood box left on the old site) will follow the right hand part of the diagram above i.e. everything to the right of the vertical red line labelled laying. Here it is expanded a bit:

Queenright splits and the window(s) of opportunity

The queen should start laying almost immediately if drawn comb is provided meaning this new brood will be sealed in a further 8-9 days. The timing and duration of the minimum broodless period depends upon whether you prime the queenright split with a small amount of open or emerging brood.

  • Open brood will be capped within about 6 days of the eggs hatching. If the frame contains nothing older than 3rd instar larvae (about mid-size) you will only have about 3 days before the cells are capped – indicated by bracketed region labelled (A) above, with capped pupae shown by the dark shaded arrow.
  • Emerging brood offers a bit more flexibility. If all the brood emerges in the first 2-3 days after the split (shown with the pale shaded arrow) then the duration of the broodless period, shown in (B) above, lasts about 5 days.

Queenless colonies after splitting

The queenless part of the split will behave like the swarmed colony in the upper line diagram. All capped worker brood will have emerged 21 days after the split (drones after 24 days).

Capped brood arising from eggs laid by the new queen in this colony will depend upon the origin of the queen.

If the colony is left to rear its own queen then the timing will be similar to the upper line diagram plus the additional time required to create a capped queen cell (which rather depends upon the state of the colony when split).

However, if you add a mature queen cell a day off emergence you will reduce the time to the appearance of new capped brood by ~8 days. Consequently the colony will probably never go through a phase with no capped brood present. This is the same, but even more so, if you requeen the colony with a mated queen.

The miticide of choice

Of all the (rather limited range of) miticides available, an oxalic acid-containing treatment is the most appropriate. Oxalic acid (OA) is well-tolerated and, if used on a colony that lacks capped brood, over 90% effective. In addition, and critical for treatment in a narrow window of opportunity, only one treatment is required.

OA can be administered by trickling or sublimation. I’ve covered both methods in detail previously so won’t repeat what’s required, or the recipes, here.

Note that in many cases although the colony will have no capped brood it will not be broodless. For example, larvae from eggs laid by the new queen will be present but uncapped.

This is important because trickled oxalic acid-containing treatments are toxic to open brood. Under these conditions the treatment of choice would be sublimated oxalic acid.

Sublimox vaporiser

Sublimox vaporiser …

Finally, note that if you are going to sublimate Api-Bioxal you’ll either have to spend ages cleaning the pan of the vaporiser, or line it with aluminium foil in advance.

The treatments outlined here are not intended for routine use. They should be used only if needed based upon mite counts or overt signs of DWV-mediated disease.

However, if you do need to treat make sure you do it when the treatment will be most effective.


 

Leave and let die

If you follow some of the online discussions on Varroa¬†you’ll see numerous examples of amateur beekeepers choosing not to treat so as to ‘select for mite-resistant bees’.

For starters it’s worth looking at the ‘treatment-free’ forums on Beesource.

DWV symptoms

DWV symptoms

The principle is straightforward. It goes something like this:

  • Varroa is a relatively new 1 pathogen of honey bees who therefore naturally have no resistance to it (or the viruses it transmits).
  • Miticide treatment kills mites, so favouring the survival of bees.
  • Consequently, traits that confer partial or complete resistance to¬†Varroa are not actively selected¬†for (which would otherwise happen if an untreated colony died out).
  • Treatment is therefore detrimental, at the population level if not the individual level, to the development of¬†Varroa-resistant bees.
  • Therefore, don’t treat and – with a bit of luck – a resistant strain of bees will appear.

A crude oversimplification?

Yes, I don’t deny it.

There are all sorts of subtleties here. These range from the open mating of queens, isolation of apiaries, desirable traits (with regards to both disease resistance and honey production 2), livestock management ethics, our responsibilities to other beekeepers and other pollinators. I could go on.

But won’t.

Instead I’ll discuss a short paper published in the Journal of Apicultural Research. It’s not particularly novel and the results are very much in the “No sh*t Sherlock” category. However, it neatly emphasises the futility of the ‘do nothing and expect evolution to find a solution’ approach.

But I’ll start with a simple question …

How many colonies have you got?

One? (in which case, get another)

Two?

Ten?

One hundred?

Eight-two thousand? 3

Numbers matters because evolution is a numbers game. The evolutionary processes that result in alteration of genes (the genotype of an organism) that confer different traits or characteristics (the phenotype of an organism) are rare.

For example, viruses are some of the fastest evolving organisms and, during their replication, mutations (errors) occur at a rate of about 1 in 104 at the genetic level 4.

This is why we treat ...

This is why we treat …

But so-called higher organisms (like humans or bees) have much more efficient replication machinery and make very many fewer errors. A conservative figure for bees might be about 10,000 times less than in these viruses (i.e. 1 in 108), though it could be as much as a million times less error-prone 5

There are lots of other evolutionary mechanisms in addition to mutation but the principle remains broadly the same. The chance changes that are acquired by copying or mixing up genetic material are very, very infrequent.

If they weren’t, most replication would result – literally – in a dead end.

OK, OK, enough numbers … what about my two colonies?

So, since the evolutionary¬†mechanisms make small, infrequent changes, the¬†chance of a beneficial change occurring is very small. If you start with small numbers of colonies and expect success you’re likely to be disappointed.

Where¬†‘likely to be’¬†means¬†will be.

The chances of picking the Lotto jackpot is about 1 in 45 million for each ticket purchased. If you expect to win you will be disappointed.

It could be you … but it’s unlikely

If you buy two tickets (with different numbers!) your chances are doubled. But realistically, they’re still not great 6.

And so on.

Likewise, the more colonies you have, the more likely you’ll get one that might – by chance – acquire a beneficial mutation that confers some level of resistance to¬†Varroa.

Of course, we don’t really know much about the genetic basis for resistance (or tolerance?) to¬†Varroa in honey bees. We know that there are behavioural changes that increase survival. We also know that¬†Apis cerana can cope with¬†Varroa because it has a shorter duration replication cycle and exhibits¬†social apoptosis.

There are certainly ‘hygienic’ and other traits in bees that may be beneficial, but at a genetic level I don’t think we know the number of genes that are altered to confer these, or how much each might contribute.

So we don’t know how many mutations will be needed … One? One hundred? One thousand?

If the benefit of an individual mutation is very subtle it might offer relatively little selective advantage, which brings us back to the numbers again.

Apologies. Let’s not go there.

Let’s cut to the chase …

Comparison of treated vs untreated colonies over 3 years

Miticides – whether hard chemicals like Amitraz or Apistan or organic acids like formic or oxalic acid – work by exhibiting differential toxicity to mites than to their host, the bee. They are not so specific that they only kill mites. They can harm other things as well … e.g.¬†if you ingest enough oxalic acid (5 – 15g) it can kill you.

Amitraz

Amitraz …

Jerzy Wilde and colleagues published their study 7¬†comparing colonies treated or untreated over a three year period. The underlying question addressed in the paper is “What’s more damaging, treating with potentially toxic miticides or not treating at all?”

The study was straightforward. They started with 100 colonies, requeened them and divided them randomly into 4 groups of 25 colonies each. Three received treatment and one was a control.

The ‘condition’ of the colonies was measured in a variety of ways, including:

  • Colony size in Spring (number of combs occupied)
  • Nosema levels (quantified by numbers of spores)
  • Mite drop over the winter (dead mites per 100g of ‘hive debris’)
  • Colony size in autumn (post-treatment) and egg laying rate by the queen
  • Winter losses

The last one needs some explanation because in one group (guess which?) there were more winter losses than they started the experiment with.

Overwintering colony losses were made up from splits of colonies in the same group the following year, so that each year 25 colonies went into the winter i.e. surviving colonies were used to generate additional colonies for the same treatment group.

Treatment and seasonal variation

To add a little complexity to the study the authors compared three treatment regimes:

  1. Hard chemicals only – active ingredients amitraz or the pyrethroid flumethrin (the research group are Polish, so the particular formulations are those licensed in Poland – Apiwarol, Bayvarol and Biowar).
  2. Integrated Pest Management (IPM) – a range of treatments including Api Life Var (primarily a thymol-based treatment) in spring, drone brood removal early/mid season, hard chemical or formic acid in late summer/autumn and oxalic acid in midwinter.
  3. Organic (natural) treatments only – Api Life Var in spring, the same or formic acid in late summer and a midwinter oxalic acid treatment.

The fourth group were the untreated controls.

To avoid season-specific variation they conducted the experiment over three complete seasons (2010-2012).

The apiary in winter ...

The apiary in winter …

The results of the study are shown in a series of rather dense tables with standard deviation and statistic significance … so I’ll give a narrative account of the important ones.

Results …

The strength of surviving colonies in Spring was unaffected by prior treatment (or absence of treatment) but varied significantly between seasons. In contrast, late summer colony strength was significantly worse in the untreated control colonies. In addition, the number of post-treatment eggs laid by the queen was significantly lower (by ~30%) in untreated control colonies 8.

Remember that early autumn treatment is needed to reduce Varroa infestation and so protect the winter bees that are being reared at this time from the mite-transmitted viruses.

Out, damn'd mite ...

Out, damn’d mite …

The most dramatic effects were seen in winter losses and (unsurprisingly) mite counts.

Mites were counted in the hive debris falling through the open mesh floor during the winter. In the first year the treated and untreated controls had similar numbers of mites per 100g of debris (~12). In all treated colonies this remained about the same in each subsequent season. Conversely, untreated controls showed mite drop increasing to ~43 in the second year and ~114 in the final year of the study.

During the three years of the study 30 untreated colonies died. In contrast, a total of 37 colonies from the three treatment groups died.

The summary sentence of the abstract to the paper neatly sums up these results: 

Failing to apply varroa treatment results in the gradual and systematic decrease in the number of combs inhabited by bees and condition of bee colonies and consequently, in their death.

… and some additional observations

Other than oxalic acid, none of the treatments used significantly affected the late season egg laying by the queen. Api Life Var contains thymol and many beekeepers are aware that the thymol in Apiguard quite often stops the queen from laying. Interesting …

I commented last week on queen losses with MAQS. In this Polish study, 8 of 50 colonies treated with formic acid suffered queen losses.

In the third season (2012) 45% of the 100 colonies died. More than half of these lost colonies were in the untreated controls. In contrast, overall colony losses in the first two years were only 9% and 13%. Survival of untreated colonies for a year or two is expected, but once the Varroa levels increase significantly the colony is doomed.

Overall, colonies receiving integrated pest management or hard chemical treatment survived best.

Evolution …

March of Progress

Evolution …

Remind yourself where the colonies came from that were used to make up the losses in the treatment (or control) groups … they were splits from colonies within the same group. So, colonies that survived without treatment were used to produce more colonies to not be treated the following season.

Does this start to sound familiar?

Jerzy Wilde and colleagues started with 25 colonies in the untreated group. They lost 30 colonies over a 3 year period and ended up with just two colonies. Had they wanted to continue the study they would have been unable to recover their losses from these two remaining colonies.

If you don’t treat you must expect to lose colonies.

Lots of colonies.

Actually, almost all of them.

… takes time

This study lasted only three years.¬†That’s not very long in evolutionary terms (unless you are a bacterium with a 20 minute replication cycle).¬†

It would be unrealistic to expect Varroa resistance to almost spontaneously appear. After all, there are about 91 million colonies worldwide, the majority of which are in countries with Varroa. Lots of these colonies will not be treated. If it was that easy it would have happened many times already.

What happens when you start with more colonies and allow more time to elapse?

Well, this ‘experiment’ has been done. There are a number of regions that have well-documented populations of feral honey bees that are living with, if not actually resistant to,¬†Varroa.

One well known population are the bees in the Arnot Forest studied by Thomas Seeley. These bees have behavioural adaptations Рsmall, swarmy colonies Рthat lessen the impact of Varroa on the colony 9.

Finally, returning to the title of this post, there is the so-called “Bond experiment” conducted on the island of Gotland in the Baltic Sea. Scientists established 150 colonies of mite-infested bees and let them get on with it with no intervention at all. Over the subsequent six years they followed the co-evolution of the mite and the bee 10.

It’s called the “Bond experiment” or the¬†Live and Let Die¬†study for very obvious reasons.

Almost all the colonies died.

Which is why the title of this post is more appropriate for those of us with only small numbers of colonies.


 

Midseason mite management

The Varroa mite and the potpourri of viruses it transmits are probably the greatest threat to our bees. The number of mites in the colony increases during the spring and summer, feeding and breeding on sealed brood.

Pupa (blue) and mite (red) numbers

In early/mid autumn mite levels reach their peak as the laying rate of the queen decreases. Consequently the number of mites per pupa increases significantly. The bees that are reared at this time of year are the overwintering workers, physiologically-adapted to get the colony through the winter.

The protection of these developing overwintering bees is critical and explains why an early autumn application of a suitable miticide is recommended … or usually¬†essential.

And, although this might appear illogical, if you treat early enough to protect the winter bees you should also treat during a broodless period in midwinter. This is necessary because mite replication goes on into the autumn (while the colony continues to rear brood). If you omit the winter treatment the colony starts with a higher mite load the following season.

And you know what mites mean

Mites in midseason

Under certain circumstances mite levels can increase to dangerous levels 1 much earlier in the season than shown in the graph above.

What circumstances?

I can think of two major reasons 2. Firstly, if the colony starts the season with higher than desirable mite levels (this is why you treat midwinter). Secondly, if the mites are acquired by the colony from other colonies i.e. by infested bees drifting between colonies or by your bees robbing a mite infested colony.

Don’t underestimate the impact these events can have on mite levels. A strong colony robbing out a weak, heavily infested, collapsing colony can acquire dozens of mites a day.

The robbed colony may not be in your apiary. It could be a mile away across the fields in an apiary owned by a treatment-free 3 aficionado or from a pathogen-rich feral colony in the church tower.

How do you identify midseason mite problems?

You need to monitor mite levels, actively and/or passively. The latter includes periodic counts of mites that fall through an open mesh floor onto a Varroa board. The National Bee Unit has a handy Рthough not necessarily accurate Рcalculator to determine the total mite levels in the colony based on the Varroa drop.

Out, damn'd mite ...

Out, damn’d mite …

Don’t rely on the NBU calculator. A host of factors are likely to influence the natural¬†Varroa¬†drop. For example, if the laying rate of the queen is decreasing because there’s no nectar coming in there will be fewer larvae at the right stage to parasitise … consequently the natural drop (which originates from phoretic mites) will increase.

And vice versa.

Active monitoring includes uncapping drone brood or doing a sugar roll or alcohol wash to dislodge phoretic mites.

Overt disease

But in addition to looking for mites you should also keep a close eye on workers during routine inspections. If you see bees showing obvious signs of deformed wing virus (DWV) symptoms then you need to intervene to reduce mite levels.

High levels of DWV

High levels of DWV …

During our studies of DWV we have placed mite-free 4 colonies into a communal apiary. Infested drone cells were identified during routine uncapping within 2 weeks of our colony being introduced. Even more striking, symptomatic workers could be seen in the colony within 11 weeks.

Treatment options

Midseason mite management is more problematic than the late summer/early autumn and midwinter treatments.

Firstly, the colony will (or should) have good levels of sealed brood.

Secondly, there might be a nectar flow on and the colony is hopefully laden with supers.

The combination of these two factors is the issue.

If there is brood in the colony the majority (up to 90%) of mites will be hiding under the protective cappings feasting on sealed pupae.

Of course, exactly the same situation prevails in late summer/early autumn. This is why the majority of approved treatments – Apistan¬†(don’t), Apivar, Apiguard¬†etc. – need to be used for at least 4-6 weeks. This covers multiple brood cycles, so ensuring that the capped¬†Varroa are released and (hopefully) slaughtered.

Which brings us to the second problem. All of those named treatments should not be used when there is a flow on or when there are supers on the hive. This is to avoid tainting (contaminating) the honey.

And, if you think about it, there’s unlikely to be a 4-6 week window between early May and late August during which there is not a nectar flow.

MAQS

The only high-efficacy miticide approved for use when supers are present is MAQS 5.

The active ingredient in MAQS is formic acid which is the only miticide capable of penetrating the cappings to kill Varroa in sealed brood 6. Because MAQS penetrates the cappings the treatment window is only 7 days long.

I have not used MAQS and so cannot comment on its use. The reason I’ve not used it is because of the problems many beekeepers have reported with queen losses or increased bee mortality. The Veterinary Medicines Directorate MAQS¬†Summary of the product characteristics provides advice on how to avoid these problems.

Kill and cure isn’t the option I choose ūüėČ 7

Of course, many beekeepers have used MAQS without problems.

So, what other strategies are available?

Oxalic acid Api-Bioxal

Many beekeepers these days Рif you read the online forums Рwould recommend oxalic acid 8.

I’ve already discussed the oxalic acid-containing treatments extensively.

Importantly, these treatments only target phoretic mites, not those within capped cells.

Trickled oxalic acid is toxic to unsealed brood and so is a poor choice for a brood-rearing colony.

Varroa counts

In contrast, sublimated (vaporised) oxalic acid is tolerated well by the colony and does not harm open brood. Thomas Radetzki demonstrated it continued to be effective for about a week after administration, presumably due to its deposition on all internal surfaces of the hive. My daily mite counts of treated colonies support this conclusion.

Consequently beekeepers have empirically developed methods to treat brooding colonies multiple times with vaporised oxalic acid Api-Bioxal to kill mites released from capped cells.

The first method I’m aware of published for this was by¬†Hivemaker on the Beekeeping Forum. There may well be earlier reports. Hivemaker recommended three or four doses at five day intervals if there is brood present.

This works well 9 but is it compatible with supers on the hive and a honey flow?

What do you mean by compatible?

The VMD Api-Bioxal Summary of product characteristics 10 specifically states “Don‚Äôt treat hives with super in position or during honey flow”.

That is about as definitive as possible.

Another one for the extractor ...

Another one for the extractor …

Some vapoholics (correctly) would argue that honey naturally contains oxalic acid. Untreated honey contains variable amounts of oxalic acid; 8-119 mg/kg in one study 11 or up to 400 mg/kg in a large sample of Italian honeys according to Franco Mutinelli 12.

It should be noted that these levels are significantly less than many vegetables.

In addition, Thomas Radetzki demonstrated that oxalic acid levels in spring honey from OA vaporised colonies (the previous autumn) were not different from those in untreated colonies. 

Therefore surely¬†it’s OK to treat when the supers are present?

Absence of evidence is not evidence of absence

There are a few additional studies that have shown no marked rise in OA concentrations in honey post treatment. One of the problems with these studies is that the delay between treatment and honey testing is not clear and is often not stated 13.

Consider what the minimum potential delay between treatment and honey harvesting would be if it were allowed or recommended.

One day 14.

No one has (yet) tested OA concentrations in honey immediately following treatment, or the (presumable) decline in OA levels in the days, weeks and months after treatment. Is it linear over time? Does it flatline and then drop precipitously or does it drop precipitously and then remain at a very low (background) level?

Oxalic acid levels over time post treatment … it’s anyones guess

How does temperature influence this? What about colony strength and activity?

Frankly, without this information we’re just guessing.

Why risk it?

I try and produce the very best quality honey possible for friends, family and customers.

The last thing I would want to risk is inadvertently producing OA-contaminated honey.

Do I know what this tastes like? 15

No, and I’d prefer not to find out.

Formic acid and thymol have been shown to taint honey and my contention is that thorough studies to properly test this have yet to be conducted for oxalic acid.

Until they are – and unless they are statistically compelling – I will not treat colonies with supers present … and I think those that recommend you do are unwise.

What are the options?

Other than MAQS there are no treatments suitable for use when the honey supers are on. If there’s a good nectar flow and a mite-infested colony you have to make a judgement call.

Will the colony be seriously damaged if you delay treatment further?

Quite possibly.

Which is more valuable 16, the honey or the bees?

One option is to treat, hopefully save the colony and feed the honey back to the bees for winter (nothing wrong with this approach … make sure you label the supers clearly!).

Another approach might be to clear then remove the supers to another colony, then treat the original one.

However, if you choose to delay treatment consider the other colonies in your own or neighbouring apiaries. They are at risk as well.

Finally, prevention is better than cure. Timely application of an effective treatment in late summer and midwinter should be sufficient, particularly if all colonies in a geographic area are coordinately treated to minimise the impact of robbing and drifting.

I’ve got two more articles planned on midseason mite management for when the colony is broodless, or can be engineered to be broodless 17.


 

The hairdryer treatment

I must be missing a couple of fingers. When I wrote the last post on hive and queen numbering I counted off the days to the end of this week, scheduled the post and was then quite surprised when it appeared on Wednesday.

D’oh!

That Friday feeling

That’s spoilt the pattern a bit.

To get back on schedule here’s a note about the well-known trick to revitalise foundation 1.

Frames and foundation

It’s the time of the season when many beekeepers will be running out of frames as they try and keep up with splits and swarming.

It’s sometimes difficult to get new foundation precisely when you need it. The suppliers sell out or delivery takes a week and you need it¬†that afternoon 2.¬†I therefore usually buy in bulk and store it somewhere cool and flat.

If you look after it properly foundation lasts for ages. Don’t go piling things on top of the stack and try not to damage the fragile edges. However, over time it becomes brittle and develops a pale waxy bloom on the surface. It also loses that lovely ‘new foundation’ smell.

The bees draw out this old rather tired foundation appreciably less well than they do new fragrant sheets. In my experience this is particularly noticeable in supers.

However, a few seconds with a hairdryer on a medium setting quickly restores the foundation to its original state.

Revitalising foundation

Don’t overheat it. The sheet will bow slightly as it is warmed. Treat both sides to try and keep it as flat as possible. The foundation will become slightly translucent and regains that lovely ‘new foundation’ smell as oils are released from the warmed wax.

It’s easier to do this once the foundation is fitted in the frame. However, old, brittle foundation is less easy to work with when you’re making up frames in the first place.

Or you could use foundationless frames ūüėČ

Your call.


Colophon

The phrase ‘hairdryer treatment’ is most often associated with the last but one, two, three, four 3 managers of Manchester United FC, Sir Alex Ferguson. The BBC’s Learning English website describes it very well …¬†When Sir Alex Ferguson was angry with his players, he shouted at them with such force, it was like having a hairdryer switched on in their faces.

Since I’m interested in etymology 4 and not football I’ve no idea what prompted the rise in use of the term in May 2013, visualised below on Google Trends.

Hairdryer treatment – Google Trends

Perhaps the May 2013 peak wasn’t Fergie or football at all … perhaps it was a flurry of articles on restoring old wax foundation ūüėČ