Tag Archives: Varroa

Winter bee production

There are big changes going on in your colonies at the moment.

The summer foragers that have been working tirelessly over the last few weeks are slowly but surely being replaced. As they die off – whether from old age or by being eaten by the last of the migrating swallows – they are being replaced by the winter bees.

Between August and late November almost the entire population of bees will have changed. The strong colonies you have now (or should have) will contain a totally different workforce by the end of the year.

Forever young

The winter bees are the ones responsible for getting the colony from mid/late autumn through to the following spring. They are sometimes termed diutinus bees from the Latin for “long lived”.

These are the bees that thermoregulate the winter cluster, protecting the queen, and rearing the small amounts of brood during the cold, dark winter to keep the colony ticking over.

A midwinter colony

Physiologically they share some striking similarities with so-called hive or nurse bees ¹ early in the summer.

Both hive bees and winter bees have low levels of juvenile hormone (JH) and active hypopharyngeal glands. Both types of bee also have high levels of vitellogenin, high oxidative stress resistance and corpulent little bodies.

But early summer nurse bees mature over a 2-3 week period. Their JH levels increase and vitellogenin levels decrease. This induces additional physiological changes which results in the nurse bee changing into a forager. They sally forth, collecting nectar, pollen and water …

And about three weeks later they’re worn out and die.

Live fast, die young

And this is where winter bees differ. They don’t age.

Or, more accurately, they age v e r y s l o w l y.

In the hive, winter bees can live for 6 months if needed. Under laboratory conditions they have been recorded as living for up to 9 months.

They effectively stay, as Bob Dylan mumbled, forever young.

Why are winter bees important?

Although not quite eternal youth … staying forever young is useful as their longevity ensures that the colony does not dwindle and perish in the middle of winter.

With little or no nectar or pollen available in the environment the colony reduces brood rearing, and often stops altogether for a period.

But what about the kilograms of stores and cells filled with pollen in the hive? Why can’t they use that?

Whilst both are present, there’s nothing like enough to maintain the usual rate of brood rearing. If they tried the colony would very quickly starve.

Evolution has a very effective way of selecting against such rash behaviour 🙁

If you doubt this, think how quickly hives get dangerously light during the June gap. With no nectar coming in and thousands of hungry (larval) mouths to feed the colony can easily starve to death during a fortnight of poor weather in June.

The winter bees ‘hold the fort’, protecting the queen and rearing small amounts of brood until the days lengthen and the early season pollen and nectars become available again.

And, just as the winter bees look after the viability of the colony, the beekeeper in turn needs to look after the winter bees … we rely on them to get the colony through to spring.

Can you identify the winter bees?

But before we discuss that, how do you identify and count the winter bees? How can you tell they are present? After all, as the picture above shows ², all bees look rather similar …

Counting the long lived winter bees

The physiological changes in winter bees, such as the JH and vitellogenin levels, are only identifiable once you’ve done some rather devastating things to the bee. These have the unfortunate side effect of preventing it completing any further bee-type activities 🙁

Even before you subject them to that, their fat little bodies aren’t really sufficiently different to identify them visually.

But what is different is their longevity.

By definition, the diutinus or winter bees are long lived.

Therefore, if you record the date when the bee emerged you can effectively count back and determine how old it is. If it is more than ~6 weeks old then it’s a winter bee.

Or the queen 😉

And, it should be obvious, if you extrapolate back to the time the first long lived bees appear in the hive you will have determined when the colony starts rearing winter bees.

The obvious way to determine the age of a bee is to mark it upon emergence and keep a record of which marks were used when. Some scientists use numbered dots stuck to the thorax, some use combinations of Humbrol-type paint colours.

I’m not aware that anyone has yet used the barcoding system I discussed recently, though it could be used. The winter bee studies I’m aware of pre-date this type of technology.

Actually, some of these studies date back almost 50 years, though the resulting papers were published much more recently.

This is painstaking and mind-numbingly repetitive work and science owes a debt of gratitude to Floyd Harris who conducted many of the studies.

Colony age structure – autumn to winter

Here is some data showing the age structure of a colony transitioning from late summer into autumn and winter. There’s a lot in this graph so bear with me …

Colony age structure from August to December – see text for details

The graph shows the numbers and ages of bees in the colony.

The ages of the bees is indicated on the vertical axis – with eggs and brood (the youngest) at the bottom, coloured black and brown respectively. The adult bees can be aged between 1 and ~100 days old ³. The number of bees is indicated by the width of the coloured bar at each of the nine 12 day intervals shown.

All of the adult bees present in the hive at the end of August are coloured blue, irrespective of their age. There are a lot of these bees at the end of August and almost all of them have disappeared (died) by mid-November ⁴.

The remaining colours indicate all the bee that emerge within a particular 12 day interval. For example, all the bees that emerge between the 31^st of August and the 12^th of September are coloured yellow. Going by the width (i.e. the numbers of bees of that age) of the yellow bars it’s clear that half to two-thirds of these bees die by mid October, with the rest just getting older gracefully.

But look at the cohort that emerge between the end of September and early October, coloured like this ⁵. The number of these bees barely changes between emergence and early December. By this time they are 72 days old i.e. an age that most summer bees never achieve.

Brood breaks and climate

In the colony shown above the queen continued laying reduced numbers of eggs – the black bars – until mid-October and then didn’t start again until the end of November. During this period the average age of the bees in the colony increased from ~36 days to ~72 days and the strength of the colony barely changed.

The figure above comes from a BeeCulture article by Floyd Harris. The original data isn’t directly referenced, but I suspect it comes from studies Harris conducted in the late 70’s in Manitoba, some of which was subsequently published in the Journal of Apicultural Research. In addition, Harris co-authored a paper presenting similar data in a different format in Insectes Sociaux which describes the Manitoban climate as having moderate/hot summers and long, cold winters.

My hives in Scotland, or your hives in Devon, or Denmark or wherever, will experience a different climate ⁶.

However, if you live in a temperate region the overall pattern will be similar. The summer bees will be replaced during the early autumn by a completely new population of winter bees. These maintain the colony through to the following spring.

The dates will be different and the speed of the transition from one population to the other may differ. The timing of the onset of a brood break is likely to also differ.

However, the population changes will be broadly similar.

And, it should be noted, the dates may differ slightly in Manitoba (and everywhere else) from year to year, depending upon temperature and forage availability.

Colony size and overwintering survival

Regular readers might be thinking back to a couple of posts on colony size and overwintering survival from last year.

One measured colony weight, showing that heavier colonies overwintered better ⁷. A second discussed the better performance of local bees in a Europe-wide study of overwintering survival. In this, I quoted a key sentence from the discussion:

“colonies of local origin had significantly higher numbers of bees than colonies placed outside their area of origin”

I can’t remember when during the season those studies recorded colony size, but I’m well aware that large colonies in the winter survive better.

The colonies that perish first in the winter are the pathetic grapefruit-sized ⁸ colonies with ageing queens or high pathogen loads.

In contrast, the medicine ball-sized ‘boomers’ go on and on, emerging from the winter strongly and building up rapidly to exploit the early season nectar.

But what the graph above shows is that the bees in a strong colony in late summer are a completely different population from the bees in the colony in midwinter.

The strength of the midwinter colony is determined entirely by when winter bee rearing starts and the laying rate of the queen, although of course both may be indirectly influenced by summer colony strength.

The influence of the queen

Other than this potential indirect influence, it’s possibly irrelevant how large the summer colony is in terms of winter colony size (and hence survival).

After all, even if the summer bees were three times as numerous, their fate is sealed. They are all going to perish six weeks or so after emergence.

Are there ways that beekeepers can influence the size of the overwinter colony to increase its chances of survival?

I wouldn’t pose the question if the answer wasn’t a resounding yes.

It has been known for a long time ⁹ that older queens stop laying earlier in the autumn than younger queens. As explained above, the longer the queen lays into the autumn the more winter bees are going to be produced.

Mattila et al., ¹⁰ looked at the consequences of late season (post summer honey harvest) requeening of colonies. In these they removed the old queen and replaced her with either a new mated or virgin queen, or allowed the colony to requeen naturally.

Using the ’12 day cohort’ populations explained above, the authors looked at when the majority of the winter bees were produced in the colony, and estimated the overall size of the winter colony.

The influence of new queens on winter bee production. Note shift to the right in B, C and D, with new queens.

With the original old queen, 53% of winter bees were produced in the first two cohorts of winter bees. With the requeened colonies 54-64% of the winter bees were produced on average 36 days later, in the third and fourth cohorts of winter bees.

This indicates that young queens produce winter bees later into the autumn.

This is a good thing™.

In addition, though the results were not statistically significant, there was a trend for colonies headed by new queens to have a larger population of bees overwinter.

Perhaps one reason the requeened colonies weren’t significantly larger was that the new queens delay the onset of winter bee rearing. I’ll return to this at the end.

The influence of deformed wing virus (DWV)

Regular readers will know that this topic has been covered extensively, and possibly exhaustively, elsewhere on this site … so I’ll cut to the chase.

DWV is the most important virus of honey bees. When transmitted by Varroa destructor there is unequivocal evidence that it is associated with overwintering colony losses. The reason DWV causes overwintering losses is that it reduces the longevity of the winter bees.

The virus might also reduce the longevity of summer bees but,

there’s so many of them to start with
there’s loads more emerging every day, and
they only survive a few weeks anyway,

that this is probably irrelevant in terms of colony survival.

Dainat et al., (2012) produced compelling evidence showing that DWV reduces the longevity of winter bees ¹¹. The lifespan was reduced by ~20%.

A consequence of this is that the winter bees die off a little faster and the colony shrinks a little more. At some point it crosses a threshold below which it cannot thermoregulate the cluster properly, further limiting the ability of the colony to rear replacement bees (assuming the queen is able to lay at a low rate).

This colony is doomed.

Even if they stagger through to the longer days of spring they contain too few bees to build up fast. They’re not dead … but they’re hardly flourishing.

Winter bees and practical beekeeping

I think there are three ways in which our understanding of the timing of winter bee production should influence practical beekeeping:

Firstly … The obvious take-home message is that winter bees must be protected from the ravages of DWV. The only way to do this is to minimise the mite population in the colony before the winter bee rearing starts.

The logical way to do this is to treat using an approved miticide as soon as practical after the summer honey is removed ¹².

I discuss the importance of the timing of this treatment in When to treat?, which remains one of the most-read posts on this site.

Secondly … Avoid use of miticides (or other colony manipulations) that reduce the laying rate of the queen in early autumn.

When I used to live at lower latitudes I would sometimes use Apiguard. This thymol-containing miticide is very effective if used when the temperature is high enough. However, in my experience a significant proportion of queens stop laying when it is being used. Not all, but certainly more than 50%.

I don’t know why some stop and others don’t. Is it genetic? Temperature-dependent?

Whatever the reason, they stop at exactly the time of the season you want them to be laying strongly.

Thirdly … consider requeening colonies with young queens after the summer honey is removed. This delays the onset of winter bee production and results in the new queen laying later into the year. The later start to winter bee production gives more time for miticides to work.

A win-win situation.

Bait hive location

We’re fast approaching the time of the season when colonies will attempt (and manage) to swarm. Swarming is the way bees increase their colony numbers.

Inevitably, because it means the loss of many of the foragers – the honey-gathering workers – beekeepers try and prevent or control swarming. Prevention is better than control, but it can be difficult or impossible to achieve.

Inevitably, a very large number of swarms are therefore lost.

The swarming process has been well-studied by eminent scientists like Martin Lindauer in the early 50’s and Tom Seeley more recently.

Swarming in a nutshell

The colony ‘decides’ to swarm. They rear one or more new queens in queen cells. On the 9^th day after the egg is laid the cells are capped. Then or shortly afterwards the colony can be expected to swarm, with the original queen and up to half of the workers leaving with her. Swarming tends to happen on a warm, calm, sunny day (but not always). Casts may follow.

The swarm leaves the hive and settles nearby, in a tree or on a fencepost. Usually this initial ‘staging post’ is a short distance (perhaps 5-20 metres) from the hive. Scout bees fly from this swarm, surveying suitable locations in the area to set up a more permanent residence.

Swarm of bees

Actually, the scouts have been hard at work already. Once the swarm issues from the hive they set about persuading all the other scouts that they’ve found the ideal location. This ‘persuasion’ is the topic of the excellent book Honeybee Democracy by Tom Seeley.

Once a consensus is reached (which might take hours or a few days) the swarm leaves its temporary staging post and flies directly to the final location … a hollow tree, the church tower or above your neighbours soffit. There they set up home.

Most swarms do not survive. They get caught in a storm before relocating, they succumb to disease or they eventually starve to death. Since most strong colonies can – unchecked – be expected to swarm every year, the fact we’re not inundated with colonies indicates that most die.

One beekeepers loss can be another beekeepers gain.

Swarms can also be an annoyance to non-beekeepers. ‘Normal’ people. This always surprises me because a swarm is a stunning site and usually totally unthreatening and unaggressive ¹.

Nevertheless, they can be an irritation, both when swarming or if they become established in the church tower or a hollow tree. And, without Varroa treatment they will act as a source of disease for other colonies in the locality through robbing and drifting ².

So, rather than just let swarms disappear over the hedge or horizon, far better to capture them, put them in a hive and manage them properly ³.

There are essentially two ways to achieve this. Get them when they’re at their temporary staging post, drop them into a box and subsequently hive them. I’ve discussed this process before.

Captured swarm in 8 frame poly nuc …

Alternatively, set up one or more bait hives and entice a swarm to choose this location rather than the church tower or a hollow tree. Again, I’ve discussed how to set up a bait hives several times before.

Bait hives in a nutshell

Honeybee Democracy contains the definitive guide to the desirable characteristics of a bait hive. Conveniently it’s a dark box the size of a National brood box (~40 litres) with a small entrance (~12.5cm²) at the bottom. It helps a lot if it also smells of bees. This can easily be achieved by placing an old black brood frame up against one wall. Fill most or all of the rest of the box with foundationless frames ⁴ and place it in a suitable location.

Bait hive …

Which is – finally – what this post is all about.

Location, location, location

Seeley studied the desirable characteristics of both the bait hive and the location in which it is sited. By location I really mean height from the ground and orientation. However, he and others have also investigated how far from the original temporary staging post the swarm are prepared to fly to occupy a ‘des res’.

So, once you’ve prepared your bait hive(s), the three features of the location you need to think about are their a) orientation, b) height above ground, and c) distance from your bees (or other apiaries ⁵).

The first two are straightforward as Seeley describes in Honeybee Democracy. In the mid-70’s he conducted a series of experiments which showed that bees prefer bait hives that a) faced South and b) are located higher (5m from the ground) rather than lower (~1m) ⁶.

Most of the studies in Honeybee Democracy use artificially prepared swarms. Seeley would place these on a post and then observe where they relocated to … essentially he was circumventing the natural process of swarming by ‘starting’ them from the staging post. Many were conducted on an island where there were limited options to relocate to … and at limited distances.

These studies weren’t ideal to determine how far a swarm will relocate from its temporary staging post.

This is important in deciding whether to place bait hives in, near or distant from established hives.

Go forth and multiply, or vice versa

It might be logical to expect swarms to choose distant final destinations rather than nearby ones. For example, this might ensure less competition for forage. That would suggest that bait hives should be situated a long way from your own – or other – apiaries.

However, it turns out that when bees multiply they usually choose not to go forth very far. Although there is some contradictory evidence, it appears as though swarms prefer to relocate to nearby sites, rather than distant ones.

Seeley and Morse (1977) demonstrated that swarms chose a nearby (~20m) site rather than a distant site (~400m) 80% of the time ⁷.
Jaycox and Parise (1981) showed that swarms always chose sites less than 200m from the artificial swarms prepared for their study ⁸.
Schmidt (1995) demonstrated that artificial swarms chose to relocate from as little as 0.5m to at least 1 km (average ~400m, i.e. much further away than the other studies) ⁹.

Why they prefer to set up home near to the original colony is unclear. At least one paper speculates it leaves the option to rob a genetically-related (and possibly less defensive) colony more easily.

Pragmatism and practical beekeeping

I set up bait hives every year. I’ve never failed to capture swarms. I’ve also – inadvertently – had swarms occupy stacks of stored brood boxes or supers. The entrances have faced almost every direction, with South East and South probably being the most often occupied.

However, this is a biased survey … I usually use the same site that worked in previous years.

Under offer …

Although I’ve located bait hives high up on the top of greenhouses or sheds, the majority are on normal hive stands. This is pragmatism, not because they are more attractive to the bees at knee height ¹⁰.

I simply don’t want to climb a ladder to retrieve them 😉

Finally, I put them where I can see them and check them. I locate one in the corner of each apiary, as far from my other hives as possible, but probably never more than 10m away.

Pleasure and practical beekeeping

I also always have a bait hive in the garden where I can observe it on a daily basis. It’s great to see the first scouts appear, to watch their numbers increase day upon day, to keep an eye on the weather for a hot calm day … and to try and predict when the swarm will arrive.

Scout bees are not aggressive. They fly in a characteristic manner, checking the bait hive and the immediate vicinity from all directions.

If the numbers of scouts builds up to dozens or hundreds and they all disappear … either they’ve chosen somewhere else or the swam has been captured.

Or they’re guiding the swarm to your bait hive at that very moment.

Wait a few minutes. A swarm arriving is one of the really great sights in beekeeping 🙂

2017 in retrospect

The end of the year is a good time to look back at the highs and lows of the season. What worked … what didn’t work … what on earth happened to our weather in June?

Early June 2017 …

June is an important month here in Fife. Early season colony buildup should be pretty much complete, most colonies will have had some sort of swarm control measures in late May, virgin queens may well be present in many hives, the OSR is over and colonies need to consolidate for the main summer flows.

But instead it just rained.

Rainfall in Fife was 225% the 40 year average, access to apiaries was problematic due to flooding and queens could only get out to mate if they were wearing ‘water wings‘.

Big mistake

Many colonies needed to be, or should have been fed, during June. Mine had reasonable levels of stores as I’d not taken much early season honey. I therefore chose not to feed them. In retrospect I think this was a big mistake.

Although not monitored carefully, I suspect brood rearing slowed, so reducing the colony size to effectively exploit the July/August flows. It was my worst summer honey crop in years.

Lesson one … If this happens next season I’ll continuously feed thin syrup to keep the queen laying strongly.

Doing the splits

Notwithstanding the incessant rain, swarm control – and the inevitable associated queen mating – went pretty well. I generally use splits of one form or another and most queens got out to mate, albeit a little slower than I’d have liked. If swarm control is needed for colonies in the bee shed we can’t do vertical splits (because of the way entrances are organised) and instead just take a nucleus colony away and let them rear a new queen.

Only ‘pretty well’ though because I suspect I lost a cast from a vertical split that went calamitously wrong. I’d left the queenless half far too strong and inadvertently also left multiple developing queen cells.

D’oh!

This wasn’t going to end well 🙁

I did manage to capture and hive another cast from the same colony, but the first virgin queen and well over half the workers were long gone.

So, lesson two (which I’ve been taught many times before 😥 ) is to be decisive when there are multiple queen cells in a split. Either knock them back appropriately (which I’ll explain next year) or split the box up into multiple nucs. Don’t dither. Don’t prevaricate and don’t – as I think I did this year – simply forget to check.

All the gear, some idea

I blatantly poached how to build foundationless frames with bamboo skewers from the internet. I claim zero originality here. It isn’t my idea. However, I’m pleased to say it was a great success. Simple wooden starter strips were also a roaring success. It’s very satisfying when you realise you don’t need to spend £1 per frame on foundation.

Nearly completed …

I’ve used quite a few Abelo poly hives this season. They’re a strident colour – blue and yellow – but reasonably well made. Colonies checked this winter are doing well in them, with bees right up to the side walls on sub-zero days. This suggests to me that they are well insulated.

An Abelo/Swienty hybrid hive …

There are some aspects of these hives I have yet to be fully convinced by; upper entrances, the crownboard, high condensation levels and a small Varroa tray. I’ll review them more fully when I’ve been using them for at least a full year.

Old invasives …

The bête noire of most beekeepers, the Varroa mite, has featured heavily throughout the year. In print, though thankfully not in my colonies. I’ve tried to emphasise the need to treat appropriately, using the right miticide at the right time. Since most approved (and even some unapproved 😉 ) miticides are all pretty effective, the timing of treatment is probably the most important point.

2016 temperature data and OA treatment …

In three recent posts I presented the importance of midwinter treatment, how to prepare the oxalic acid-containing miticide and how to administer it. These should probably be read in conjunction with an earlier article on when to treat, which I’ll come back to in a minute. Finally, as far as Varroa is concerned, I discussed potential ways to optimise the timing of the winter treatment by watching the weather. I suspect that most beekeepers treat too late in the winter.

If you have yet to treat this winter … get a move on!

… and new ones

The new invasive that got some coverage was, inevitably, the Asian hornet. Having first arrived in 2016 I think we’ll be subjected to annual incursions until it gets established here. Constant vigilance is going to be needed to help postpone what might be inevitable. Just because it is inevitable doesn’t mean we shouldn’t try and delay it’s permanent arrival.

Devon beekeepers got some first-hand experience of how vigilant you need to be to both spot and photograph Asian hornets in September. Martin Hocking has written about his experience in the Devon Beekeeper (pp172 and also in November’s Bee Craft) which should be required reading for beekeepers, with a follow up article about his experience in December (see pp196). There’s an open meeting on the 20^th of January at Harberton Parish Hall, TQ9 7SD where the threat posed by the Asian hornet – and how to mitigate it – will be discussed.

Although rarely mentioned this year, Small Hive Beetle now appears to be established in the Calabria region of Southern Italy. Data updated in late September and November indicates that positive wild colonies and sentinel nucleus colonies are still being found, indicating that attempts to eradicate the beetle have failed. Infested colony numbers are perhaps a bit lower than previous years, but since there’s no readily-available data on the level of surveillance, it’s not clear whether this shows that control is having an effect, or if people are just not looking as hard.

www.theapiarist.org

Posts have been made every Friday of the year, with a few additional ones when something important happened (Asian hornets or I was ‘advertising’ a Convention I was speaking at … OK, my talk wasn’t important, but the Welsh Beekeepers Convention was 😉 ).

Regular as clockwork …

The Friday posts are intentional. It’s when most of us have time to read stuff. The regularity was not and, frankly, it’s a bit of a surprise I’ve achieved it. However, there it is. No promises it’ll continue like that. You can register to receive email notification of new posts in the right hand panel.

Visitor numbers to the site are markedly increased from last year. Page views per visit are down fractionally, but not significantly. It’s clear that more are finding the site as it becomes better indexed by the search engines, and as pages are referenced by other sites.

24 months on www.theapiarist.org …

My attempts at generating a presence on Facebook was an abject failure. I simply don’t have time to do anything other than automagically post updates from here on Facebook (as I do on Twitter, which I’m a bit more familiar and competent with … follow me on @The_Apiarist). Apologies if you tried to ‘Friend’ me (or whatever) on Facebook. I’ve cancelled all the email updates as I simply couldn’t keep up. Or, when I tried, I didn’t know how to! I belong to the pre-FB generation, or the one before that.

Beekeeping is international, with different problems – but many shared ones – globally. I’m grateful to the visitors from 161 different countries and the European Union 🙂 Less than 50% of the readers are from the UK, despite the UK-centric bias I inevitably exhibit (°C, colour, no mention of queen castles or slatted racks, precious little discussion of Langstroth hives etc.). Southern hemisphere beekeepers don’t even do things at the same time of the year, so many of the posts aren’t even topical for readers in Australia, New Zealand and South America. Whatever, I’m grateful people took the time to visit and read stuff.

And the winner is …

I don’t publish visitor numbers, but I do comment on the popularity of particular pages. For several years a post on my honey warming cabinet has been the most popular. It was originally posted ‘way back’ in 2014. Frankly, it was useful, but not particularly challenging or exciting.

But it’s all change this year. Aside from the homepage, the archive and blog pages, all of which people arrive at to to get the most recent posts, the honey warming cabinet post was a distant fourth in the 2017 rankings.

Above it were posts on vertical splits and making increase, feeding fondant and – particularly pleasingly and top this year – when to treat colonies with miticides against Varroa. I say particularly pleasingly as the When to treat? post is a serious article on an important subject, underpinned by scientific arguments. The timing of the late summer treatment is probably one of the most important events in influencing the health and overwintering success of the colony. This post was almost twice as popular as any other post this year which – because it originally appeared in early 2016 – suggests it is finally being widely cited and accessed by beekeepers.

When to treat? Finally getting read when it should be.

And what does the future offer?

Frankly, as I write this in mid-December with a streaming cold, a box of tissues and slathered in Vicks VapoRub (really, it’s not a pretty sight) I don’t know. I have two priorities at the moment; getting the new bee shed properly setup and (with my researcher hat and lab coat on) starting studies of Chronic Bee Paralysis Virus. Both will get coverage here.

Bee Shed 2 … the windows still need some work …

In terms of the website I’m acutely aware there’s no proper indexing or rational list of articles on particular subjects, perhaps other than Varroa. I hope to bring some order to the chaos, allowing me to not repeat myself, to develop some themes more fully and to not repeat myself 😉 . I also know I have a load of unwritten stuff on queen rearing.

Winter time is also DIY time … dabbling with wood, perspex, Correx and Elastoplasts. Something will surely result from this, in addition to the blood loss and bad language.

If there are things you’d particularly like to read drop me a note. I’m interested in the science underlying beekeeping and have little patience with some of the dogma and That’s the way we’ve always done it stories. I’ve already written about the importance of training and the responsibilities of beekeepers. I’ve got some more on these areas planned as I think they’re too often ignored by beekeepers in the UK.

With Best Wishes for 2018. May your colonies be docile, your supers unliftable, your queens well-mated and your swarms (again) in my bait hives 😉

Happy New Year

If Carlsberg did vaporisers …

… they’d make the Sublimox sublimator.

I wonder how many beekeepers have one of these on their wish list for Santa?

Sublimox vaporiser …

From being a bit of an imported oddity (I had to import mine from Icko Apiculture in France three years ago) they’re now becoming mainstream … over the last year or so they’ve been sold by an independent importer, then Abelo and – just this month – the ‘Big Daddy’ of UK beekeeping suppliers, E. M. Thorne (Rebecca at Thorne’s kindly asked if they could include links in their December newsletter to previous posts here on the Sublimox and vaporising Api-Bioxal).

The Sublimox is also now being discussed more widely on the online forums, with much of this discussion emphasising the price (they are expensive). Aside from this disadvantage, I think there are a number of significant advantages of this design of sublimator (vaporiser) which are worth emphasising.

The general principle of active and passive sublimators

Sublimators (vaporisers) are designed to heat oxalic acid (OA) crystals sufficiently that they sublimate i.e. go through a phase transition from a solid into a gas without an intervening liquid phase. As readers of this site should know, oxalic acid is highly effective against the Varroa mite – both by sublimation and trickling in solution, which has recently been covered in excruciating detail so won’t be elaborated on here.

Varrox

Many sublimators (vaporisers) are passive. You add the OA to a pan, slide it into the hive entrance, apply a current to heat the pan, allow the OA to sublimate, withdraw the pan and start again. You usually need to cool the pan in water before addition of the next dose. This heat, rinse and repeat cycle takes time, but is very effective and the pan-type vaporisers are relatively inexpensive (£35-£100).

The Varrox vaporiser is one of the original and best known models, though there are any number of much less expensive copies sold by beekeeping suppliers and on eBay. Most require a 12V supply of some kind.

In contrast to these, the Sublimox is ‘active’, as is the US equivalent machine, the ProVap 110. In these the pan is pre-heated, the OA is ‘dropped’ into the pan in such a way that the vapour is generated in an enclosed space which it then escapes under pressure through a nozzle.

Probably the best sublimator in the world …

In terms of speed, convenience and ease of use I’d argue that the Sublimox is hard to beat.

Quick

Delivery of a single dose takes no more than 45 seconds from inserting the Sublimox nozzle into the hive. It’s appreciably faster than the pan-type passive sublimators. There’s a preliminary warming up period before use, as the machine reaches operating temperature. After that it’s simply treat, refill, treat, refill ad infinitum. The rate-limiting step is sealing the hive and refilling the small plastic ‘cartridge’ with OA.

For one person, a hive-a-minute is just about possible – if you have 10-20 closely spaced hives, sufficient entrance blocks and buy additional white plastic cartridges. But, to achieve this you’ll be rushing about like a mad thing and it’s not realistically achievable¹.

But speed isn’t the major benefit.

Convenient

Sublimox vaporiser

It’s convenient because you can ‘squirt’ the gas through a small hole in hive. You don’t need to open the hive and so it works with any hive type or entrance. My favoured kewl floors cannot be used with a sublimator that needs to be pushed through the entrance. Instead, all my hives have a neat 6mm hole drilled through the sidewall of the floor which is usually plugged with a small foam bung or twist of grass². Vapour quickly permeates throughout the hive, ensuring all surfaces are reached.

The only exception are the all-poly hives, such as the garishly coloured Abelo’s I’ve been using for work this season. The nozzle of the Sublimox gets hot and melts polystyrene (been there, done that 🙁 ). With poly hives I usually use a simple shallow eke with a Sublimox nozzle-sized hole in one side. In this case you do need to remove the roof and crownboard, add the eke, replace the roof (upside down), treat and then close up the hive.

Foam bung …

The alternative is to simply squirt the gas through the open entrance. This isn’t ideal as some of the gas will escape, potentially exposing the beekeeper and definitely not exposing the bees/mites. One way to avoid this loss of gas is to use a wooden block with a small hole through the middle held over the poly hive entrance.

It’s important to have a clear space into which the gas is ‘squirted’. If you don’t the OA tends to not permeate through the hive properly.

The Abelo hives have a hole in one face of the brood box. This is usually plugged. I think it’s intended as an upper entrance. I’ve yet to try poking the Sublimox nozzle through this hole to deliver the OA … this might not work as it may be too close to the frame, so impeding the spread of gas through the box. Time will tell^†.

Safety considerations

There’s an additional benefit of the way the Sublimox is used. Operator exposure to OA should be minimised. The gas isn’t generated until the machine is inserted and inverted and takes no more than ~45s to deliver. If the hive is sealed properly there’s very little exposure to the gas.

… but all this comes at a cost

The Sublimox is three-times the price of a Varrox vaporiser. Is it worth it? That’s up to the purchaser to decide, based on the number of hives to be treated, the depth of their pockets, the perceived benefits of the speed, ease of use, convenience and safety etc.

Many will baulk at the cost. Some build their own. Others don’t bother vaporising, but solely dribble OA solution in midwinter. This is the cheapest and fastest way to treat colonies. I estimate it costs about 0.5p/hive to trickle treat if you buy OA in 25kg bags. Dribbling is probably even faster than using the Sublimox. However, dribbling is really only practical for broodless colonies – swarms and for midwinter use – and should only be done once per season. In contrast, repeated sublimation is tolerated well by colonies.

Would I buy another one?

Almost certainly.

Before you splash the cash

Generator …

Be aware … the Sublimox requires a 240V supply. One of my apiaries has mains power which is the best solution, but unlikely in the corner of a farmers field. You can use an inverter from a car battery which is fine if you can get your car close enough to the hives. Alternatively – and this is what I do – you can use a portable generator. I’ve got an 700W Impax one from Screwfix which works perfectly.

But that’s another £190 🙁

You’ll also need to periodically buy replacement sealing rings for the OA “cassette”. These wear out or perish rather fast. Icko sell them for a daft price, but they’re now available in the UK.

Single use …

You should also be aware that Api-Bioxal, the VMD-approved oxalic acid-containing miticide, has glucose in it which caramelises in the pan of the Sublimox (and other vaporisers) and is a bit of a nightmare to clean out properly. I’d go further and suggest that Api-Bioxal is unsuitable to use with a Sublimox. If the nozzle is blocked the gas has to escape and there could be inadvertent exposure of the operator.

Safety first

I’ve touched on safety above. However, just because OA vapour is generated for a very short and well defined time doesn’t make it safe. There are still exposure risks which must be taken seriously.

You’ll need PPE – personal protection equipment – to prevent exposure to the OA vapour when treating colonies. This includes eye protection and a suitable vapour mask. Don’t skimp on this and assume you’ll just stand downwind. If the hive is poorly sealed, swirling gusts of wind will expose you to vapour and it’s – at best – very, very unpleasant.

Entrance block …

Unlike passive vaporisers, the Sublimox generates a very large volume of gas immediately the OA is added. There’s no opportunity to ‘stand well back’ as the pan warms up as you can with the passive machines. You have to be holding the Sublimox to invert it and drop the OA into the pan. You’ll be bent over the hive and unable to avoid the swirling fog of acidic vapour if it escapes. To help minimise this seal the hive thoroughly. I use a full-width entrance block and tightly fitting Varroa tray. Even then, particularly on ageing cedar hives, there are all sorts of little gaps from which the OA vapour can be seen escaping.

Entrance block in use …

Finally, as if gassing yourself with an evil smelling acidic cloud of OA wasn’t enough, remember you’re using a 240V supply outside, probably on damp grass … or possibly even in the rain. Don’t get electrocuted. Make sure you use an RCD (residual current device) that’s been tested and you know works.

Take care.

Share the costs

At the time of writing the Sublimox costs over £300. Perhaps competition will force the price down a bit? When you consider that these machines are used relatively infrequently during the season it makes sense to consider purchasing them as an Association item (or with a group of friends), in the same way that some associations have extraction equipment available.

When compared to a reasonable extractor the Sublimox doesn’t seem so outrageously priced.

Of course, like an extractor, everyone needs it at about the same time of the season (at least in midwinter). However, unlike an extractor, it’s generally needed for a relatively short period, is easy to transport and easy clean after use. There should be no reason it couldn’t be shared by association members.

I appreciate that many associations don’t have shared equipment, or many beekeepers don’t belong to their local association. All I’m doing is suggesting a way in which a good quality and highly effective piece of equipment could be purchased so that many can benefit.

Whether you’ve got one of these on your list for Santa or not …

… Happy Christmas!

¹ The rate-limiting step is probably having enough entrance blocks. If removed too soon you’ll lose lots of vaporised OA goodness. Leave it a good 5 minutes if at all possible, which is easily enough time to treat another 5 hives. See what I mean?

²When treating a hive for the first time I’ve even drilled this hole through an occupied hive.

^†Actually, this hole isn’t suitable. It opens onto the face (rather than end) of a frame, and the vapour is therefore restricting from spreading. Don’t bother.

^‡I’ve regularly treated colonies in the dark. Sometimes the only time I can get to the apiary is after work. The bees are all ‘at home’ but you can easily seal the hive up and treat them. Use a headtorch with a red bulb. Since bees can’t see red, any that escape won’t directly target your head and you can probably work safely without a veil.

Colophon

If Carlsberg did … is one of the most recognisable advertising campaigns of all time. Originally created in 1973 it has achieved near-universal recognition and remains in daily use, though predominantly these days as internet memes. The opening three words of the adverts were as recognisable as the closing seven … probably the best lager in the world.

There are any number of comedic If Carlsberg did ‘advertising’ campaigns, including some from Carlsberg itself … Probably the best poster in the world, featured the distinctive swirly underscore, colour scheme and font, together with a real tap dispensing lager installed in Londons Brick Lane.

If Carlsberg did …

Carlsberg revamped the advertising campaign in 2015 (the poster above was part of this), over 40 years after it was first used. You can view these adverts on the Carlsberg website.

I’ve used a variant of the If Carlsberg did … phrase previously, when describing the large Dadant smoker. It’s still a great smoker.

Bee shed 2: the sequel

All good things must come to an end, though this particular one did sooner than I’d hoped.

Our research apiary – affectionately known as The Bee Shed – lies in the path of a recently announced new road development. Not close to, not within sight of, but actually underneath a proposed access road to the new Madras College site to the West of St. Andrews.

Under construction (mid/late 2015) …

The timing stinks

There are actually two preferred access road routes to the new school, but the Council (who in their infinite wisdom drag everything out to the last possible minute before committing) won’t decide which will be used until about a month or so before development is expected to start. This is intended to be early in 2018 i.e. rather too close for comfort if we don’t want our research interrupted.

We’ve known about the possibility of the new road since June, but things never seem to move as fast if there’s not a deadline looming.

We therefore need to prepare a second research apiary, move all the bees across and then disassemble the original one … all within the next few weeks.

Time spent in reconnaissance …

… is seldom wasted^†. And we’ve spent quite a lot of time. We’ve considered a number of alternative sites, some better than others, but none truly ideal.

Given the choice we’d have selected a sheltered, East/South facing site, surrounded by mature open woodland, with water close by, protected from strong winds by the adjacent woodland or walling, with abundant local wildlife, early pollen and …

No, stop, wait!

The bee shed in autumn (2016) …

That’s a description of the current site.

In fairness, there were some issues with the original apiary location. It was low lying and prone to minor flooding. Access was across a rickety set of scaffolding planks that threatened to pitch us into the burn when wet and slippery. Crossing the burn with the hivebarrow – particularly in the dark – required some courage (or stupidity). There was no power in the shed, it was quite remote and it was a bit on the small side.

There were some wonderful orchids though …

Common spotted orchid …

I suspect these will struggle to re-emerge through the tarmac of the new road 🙁

Bigger and better

We’ve had to compromise on the new location, but – in doing so – we’ve managed to correct some of the shortfalls of the original site.

We’ll now have much more space and better drainage. We’ve achieved the former simply by specifying a larger footprint, and the latter by building on an earth mound raised a few feet above the water table. We’ve invested in solar powered lighting systems and have excellent shelter from the cold Easterlies that sweep in off the North Sea.

It’s also better located for outreach activities and closer to the research labs.

The final plans include a 15m x 15m platform to house a new bee shed of 16′ x 8′. Once we’ve vacated the original shed (a tiddly 12′ x 8′) it will also be moved to the new apiary, giving us additional storage and colony space.

In total we should have capacity for about a dozen colonies under cover, with more outside if needed. I should have added earlier … the two primary goals of housing bees within a shed is to provide greater protection, enabling both a slightly longer brood rearing season and allowing inspections and brood harvesting whatever the weather.

If we absolutely have to inspect/sample on a Monday morning during a downpour, we can. The beekeeper saunters over under an umbrella, dons his/her bee suit and does the work. The bees don’t react badly to inspections in inclement weather. They simply exit the shed via the windows and re-enter the hive by a short tunnel through the shed wall.

Landing boards …

Over the next few weeks I’ll document some of the developments as we start to prepare for the 2018 season.

Here’s what I prepared earlier

Here are a couple of photos of the apiary in the very early stages of preparation.

Dig and Dug build an apiary

The compacted grit base and shed foundations are now complete, with the shed and the fencing due shortly … and then it’s my turn to have a dabble preparing the shed for the bees, installing the windows and entrances and the solar power lighting system.

Early/mid December foundations and base installed

More of the same.

Shed foundations

And then there’s the small task of moving the bees in …

^† This quote (Time spent in reconnaissance is seldom wasted) is sometimes attributed to the talented and successful German Field Marshal of World War Two, Erwin Rommel. However, there are numerous other proposed sources … Sir MacPherson (Mac) Robertson (1860 – 1945), Field Marshal Arthur Wellesley The 1^st Duke of Wellington (1769 – 1852) or Sun Tzu (544 BC – 496 BC) in The Art of War. Take your pick. The meaning is self-evident … when planning something it’s worth considering all the possibilities, in particular the environment.

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