Winter wait

Synopsis: In the winter bees are low maintenance, but they’re not no maintenance. You need to carry out a few regular winter checks to help them overwinter successfully. Here are the first two things to check … I’ll deal with the third and final check next week.

Introduction

The ‘beekeeping season’ runs from spring until autumn. Quite when it starts and stops depends upon your latitude and enthusiasm 1.

More of each have opposing effects in the spring.

More latitude and the season starts later, more enthusiasm and you might be tempted to start colony inspections (the first ‘proper’ beekeeping of the year) in early spring.

I’m certainly enthusiastic but I live in Scotland. I therefore rarely open a hive before mid/late April. In some seasons it might even be mid-May.

But that doesn’t mean that there’s nothing to do between the end of the preceding season and the start of the next.

The winter wait (for the start of the season) doesn’t meant that there’s nothing to do.

During the winter months of the year bees are really low maintenance, but they’re not no maintenance.

You need to check the hives at about monthly intervals. More frequent checks will do no harm – these are ”The bees don’t even know they’re being checked” checks – but probably aren’t necessary. These checks are important to ensure the bees overwinter successfully.

Spring is on the way … Fife snowdrops, mid-February 2022

Of course, you should also check after high winds or heavy rain (very timely as I’m writing this as Storm Eunice bears down on the south west) as an overturned hive or a badly flooded apiary aren’t conducive to colony survival.

So, what do these checks entail?

What are you actually looking for?

How can you tell much of anything from an inanimate cedar or poly box on a miserable, cold, wet February afternoon?

Essentially it comes down to three things … the state of the colony, access to the hive and weight.

What’s happening in the box?

Mid-February, it’s 5°C, there’s a squally northerly blowing intermittent sharp hail showers down from the hills. No self-respecting bee would venture out in conditions like these.

Most self-preserving beekeepers would probably prefer to be sat in front of the fire reading Gilles Fert’s Raising honeybee queens 2.

However, there’s work to be done.

What on earth can you judge about what’s happening inside the box on a day like this?

If you’re a relatively new beekeeper (and this applies to some of us who have been keeping bees for many years) you would probably like to know if there are any live bees in the box.

After all, you’ve not see a flying bee for months.

Perhaps they all froze to death in those heavy frosts over the previous week?

Don’t rap sharply on the outside of the box and listen for an answering angry buzz. Yes, it’s a way of detecting whether there’s ‘life in the old box yet’, but it’s an unnecessary disturbance for the bees.

How would you like it?

There are two relatively simply methods, one much more useful than the other.

The first is to use a clear perspex crownboard on the hive 3. It’s then a simple matter to lift the roof and observe the state of the colony.

Colony viewed through a perspex crownboard – mid-February 2022

Here’s one of my colonies from last weekend. I can tell from the size of the cluster that the colony is reasonably strong.

That’s a good start.

The bees are moving on the periphery of the cluster, so they’re alive 4.

In addition, though it’s not entirely clear from this photograph, there are at least 2-3 frames of capped stores at the opposite side of the hive to the cluster.

Condensation

One of the things missing from the picture above is any significant amount of condensation on the underside of the perspex crownboard. This is because the deep inner rim of the crownboard is usually filled with a 50 mm thick block of insulation.

Perspex crownboard with integrated insulation

This is essential unless the roof is very well insulated. Without insulation immediately above the perspex the high level of humidity within the hive will lead to large amounts of condensation on the underside of the perspex.

This condensation – or at least some of it – will then drip down onto the cluster, making it a pretty unpleasant environment for the bees.

So, by simply building a ‘window’ into the top of the hive you can determine the size of the colony, whether it’s alive and possibly judge something about the level of stores in the hive.

All of which, and more, you can achieve another (better) way … read on 😉

I quite like the perspex crownboards I use on some of my colonies. However, I consider them far from essential and can judge the state of the colony much better by ‘observing’ them from below rather than from above.

Open mesh floors

When I say ‘observing’ them from below, I don’t mean a glass bottomed hive and I don’t mean directly observing them from below 5.

If you use open mesh floors (hereafter OMFs) you can collect and inspect what falls through the floor and get a very good idea of the size, state, health and activity of the colony.

Wow 🙂

An OMF should have a white (or pale yellow) coloured plastic tray or sheet that can be slid underneath the floor to catch the debris that falls through.

Not black and definitely not Varroa-coloured 😉

White polystyrene Varroa trays really need painting as they discolour badly after a couple of seasons.

Abelo poly Varroa tray

Abelo poly Varroa tray – draughty and easily discolours. Yuck.

A well designed OMF – and there are many that are not 6 – should have a close-fitting tray so that those gusty February squalls don’t disturb the debris that falls through. The position and type of debris is important and if it has been blown about all over the place – or half-eaten by slugs or ants – then your task will be that much harder.

Or impossible.

Varroa tray – single brood box, busy colony, mid-February 2022

This is a tray from a reasonably strong colony in a single brood box. You can just about make out 10 fuzzy horizontal lines of debris. These lines are made up of stuff that’s fallen through the OMF.

You realise that ‘stuff’ is a highly technical beekeeping term that covers everything from antennae, legs, wax cappings, pollen and Varroa to a range of other unidentifiable crap 7.

Tasseography

Tasseography (or tasseomancy) appears to be an entirely made up word 8 for reading tea leaves.

Deciphering the debris on a Varroa tray is a more exact science than tasseography which – and at the risk of offending any fortune-teller-beekeeping readers – isn’t.

It’s not science and it’s not exact 9. The existence of well-reviewed books on the subject proves nothing other than the gullibility of purchasers I’m afraid 10.

So, let’s look again at the debris in the picture above.

The four rows in the centre/top are darker. These are directly below the cluster and are cappings produced (and dropped) as brood emerges. Brood capping are biscuit-coloured (think a sort of dark digestive, not a pale custard cream), presumably because of the incorporated pollen and associated pupal casings.

In addition, mixed in with these rows is some paler granular debris, and there is a lot more of this in the very obvious rows towards the bottom of the picture.

These are the wax cappings that are produced when the bees uncap stores. If you have a close look at these rows you can also see some white or off-white sugar crystals.

So, we can tell the approximate size of the brood nest, we know they’re rearing brood and that they are busy uncapping stores.

Hive health

The one thing you won’t see on that tray are any Varroa 11. That particular tray was left in situ from 17/1/22 to 13/2/22. I can therefore be reasonably confident that the colony is healthy, with low Varroa levels.

I can see a tall, handsome stranger in your future … and a lot of Varroa

This second tray is from another colony in a single brood box. They are also rearing brood but have yet to venture much beyond the cluster when uncapping stores.

However, looking closely at this tray I can see a disappointingly high Varroa drop … somewhere in the region of 30-50. Again, this tray has been under the colony for a month, so I’ll need to monitor Varroa levels carefully as they build up during the spring.

As an aside, both these colonies have an identical record of miticide treatments 12 and both are in the same apiary. My records show that the colony with the higher Varroa natural drop (i.e. not due to recent treatment, the tray was cleaned in mid-January and they were last treated in November) in winter have consistently had higher mite levels.

All other things being equal – e.g. temper, behaviour, frugality 13 – I would choose to rear queens from a colony with the low mite levels.

The colony that first Varroa tray was from are not ‘mite resistant’.

They will have Varroa.

My post-treatment mite counts showed a modest mite drop and I’m confident that the treatment will have been no more than 95% effective. However, low mites are better than loadsa mites 14 and it will be interesting to see if colonies headed by daughter queens behave similarly.

Entrances

The late summer/early autumn colony reduces in size as the year progresses and as bees die off. At some point in early spring that daily births outnumber daily deaths (Murray McGregor calls this ‘crossover day’) and the colony starts to expand again.

So what happens to all those corpses?

The bees fall down through the cluster to the hive floor. On good flying days the undertaker bees will carry these away and discard them outside the hive.

However, during protracted cold or wet periods when the bees cannot fly the corpses can end up covering the floor and eventually blocking the hive entrance.

Multi-purpose Swiss Army penknife for beekeepers (sort of)

So the second check you need to perform is to ensure that the hive entrance is clear. This might mean removing the mouseguard and gently raking out the accumulated corpses.

In the kewl floors I favour the L-shaped entrance requires a correspondingly L-shaped piece of wire (a repurposed stainless steel spoke from a bicycle wheel) to check it’s clear. The same tool works perfectly well on almost all other hive entrances as well.

Be aware that you might inadvertently disturb workers near the hive entrance … these can fly out and aggressively ‘ask’ you to move away 15.

Tunnel entrances

The only entrances this multipurpose-and-soon-to-be-patented tool 16 is unsuitable for are those on the hives in my bee shed.

Entrance duct and hive floor ...

Entrance duct and hive floor … brood box removed for clarity

These have a 6” tunnel entrance. Even with a torch it’s difficult to see whether the inner hive entrance is blocked or not.

However, since you’ve already removed the Varroa tray it’s easy to look up through the OMF and check it’s clear.

There are two ways to do this:

  1. Prostrate yourself and look though the OMF while at the same time getting a gentle dusting of the stuff raining down from the cluster, or
  2. Use the phone on your camera to take a quick photo (you’ll need to use the flash).

Nothing to see here … other than some clown photobombing the hive checkup

If you do find the floor covered in corpses and the entrances blocked – whether the hives are in a shed or outside) it’s very important to clear them before leaving the apiary.

Blocked Kewl floor

Blocked Kewl floor …

Simply separate the brood box from the floor, no need to remove the crownboard, set it gently aside. Clear the floor and the entrance and replace the brood box.

Fortunately, the floors of my hives were all reassuringly clear of corpses.

In the photo from underneath the floor you can see the bottom bars of the frames and, between them 17 the serried rows of bees on the underside of the cluster. There are a lot of bees in the box.

Winter weight

So, without disturbing the colony you now know:

  • the colony is alive
  • they are rearing brood
  • stores are being consumed
  • something of the strength of the colony (in terms of number of seams of bees present)
  • whether they have low or high Varroa levels
  • if they are free to fly when the weather becomes suitable

Not a bad result for 5 minutes work.

But there’s one more thing to check.

Do they have sufficient stores to survive until your next visit to the apiary?

Actually, not just survive, but do they have sufficient stores to continue to rear brood so that the colony expands to be strong enough to exploit the early season forage when it’s available.

And I’ll deal with that question next week as I’m already fast approaching 2500 words 18 and there’s quite a bit more to cover on hive weights and winter feeding.


 

Footnotes

  1. And it varies from year to year anyway.
  2. On which, more in a later post …
  3. I’m using the tradename ‘Perspex’ here when in fact these are all probably generic polycarbonate sheet (or reclaimed shower panels).
  4. Which is also reassuring.
  5. Though I’ll return to this in a few minutes.
  6. Abelo, I’m looking at you …
  7. Though hopefully not actual crap, if you’ll excuse the term, as the bees should not defecate in the hive. I’ll cover this in an already half-written future post entitled ’A thesis on faeces.
  8. By which I mean it doesn’t exist in the Oxford English Dictionary … but then anti-vax didn’t make it into the OED until 2021 despite Edward Jenner complaining about the Anti-Vacks in 1812, so I’m not sure what that proves.
  9. In fact, it’s total hogwash.
  10. Which reminds me … my book on reading Varroa trays is being self-published and will be available from Amazon shortly.
  11. Actually, there is one, partly obscured by some wax cappings, but I didn’t want to spoil the story.
  12. Apivar in early autumn and oxalic acid during a broodless period in early/mid November.
  13. And they won’t be. Actually, they definitely are not. The colony with high(er) Varroa levels are lovely bees; calm, steady on the comb, faultless brood pattern, frugal etc. Pity!
  14. Sorry.
  15. I don’t need to tell you that I learned this the hard way. Fortunately, even the most aggressive bee soon runs out of steam when it’s 4°C and drizzling steadily.
  16. If Thorne’s can sell ~20 hive tools including the combi-brush there’s surely a market for one of these gadgets?
  17. At least in an enlarged copy of the pic.
  18. And 2am in the morning … :-(

25 thoughts on “Winter wait

  1. Frazer

    Hi David, with one eye half open in Kent, I am still trying to learn about varroa (having gave up from 1990 to 2 years ago because of them) so esp. interested in hearing about your high mite drop hive surviving so well.
    I did not treat last summer, and by October had lost half my hives and the others diminished from super-strong to 4 frames of pathetitude (thats another one for the OED 🙂 )
    so this year, I really need to ramp up my varroa protection. . I did manage to get the drop rate down to 1-3 per 24 hrs, but frustratingly, no loweradter 4 weekly OA doses of 3mg Apibioxal.

    I guess what I am saying is what are you going to do with your high(er) loaded hive?

    thanks again for your sage words, and your broadcast via Medway BKA a few weeks ago

    Reply
    1. David Post author

      Hello Frazer

      I’ll be keeping a close eye on them through the spring. I’ll uncap some drone brood and look at the level of infestation. I’ll then probably monitor phoretic mite levels by doing an alcohol wash on a cupful of bees during the June gap. If that’s higher than I’d like I’ll probably enforce a brood break and treat with oxalic acid. It’s also possible to treat during swarm control if you’re careful with the timing.

      I’m not convinced that repeated doses of OA are the best way of minimising mite levels. If I was doing repeat doses I’d be tempted to try at 4 or 5 day intervals, not weekly. There’s some old data showing some efficacy out to about day 6, but I think it’s reducing all the time. So, 7 days might be providing an day or two for them to escape attention from the OA.

      Of course, 3 milligrams is also about 500-fold too little 😉 I usually use 1.6 grams per brood box (that’s what my measuring scoop accommodates!).

      Cheers
      David

      Reply
  2. Sue

    Thank you David.
    It is always helpful to read your posts about winter tasks. Your photos illustrate so well the points you are making and it is great to have them to compare with my varroa boards!
    You help keep beekeeping alive through the winter!
    What about a post on all the winter bee equipment tasks? I seem to postpone and procrastinate these. Time is now running out!
    Thanks
    Sue

    Reply
    1. David Post author

      Hi Sue

      I’ve written quite a bit on equipment over the years and I’m not sure there’s much new to say … I’ve built roofs, floors, split boards, fat dummies and a variety of boards for queen rearing such as Cloake and Morris boards. I’ll cover the latter in the future if/when I use them again this season. There’s even an overview of this topic I posted back in October ’21.

      I don’t think there’s much else I do with equipment over the winter. It just sits around in big stacks getting in the way 😉

      Cheers
      David

      Reply
  3. Kasandra S.

    Thank you for this post and updating the dangers of the kewl floors. I was thinking about experimenting with a couple to keep out wasps, but your description of how to unblock the entrance is not possible here in Wostok, AB.

    My hives have 2″ of foam on the sides, with 4″ on top, nothing is getting taken apart until mid April. Though I do take the brick off and check position and stores when above 0°C, calm and sunny.

    Reply
    1. David Post author

      Hi Kasandra

      I think I’ve only had a couple of hives ever having problems with those kewl floors. However, if you definitely cannot open the hives due to insulation/climate I guess it’s best to avoid them. Presumably wasps disappear before you wrap the hives for winter? You could always swap them off a summer kewl floor to a winter whatever-you-use floor then.

      They do benefit the colony in terms of wasp defence …

      Cheers
      David

      Reply
  4. Frazer

    Oh |David, me and my millimetrics! ok, yes, a scoop.
    thanks for the advise on times. I shall add that to my facts spreadsheet…
    BR & thx again,

    Reply
    1. David Post author

      Hi Frazer … I take no credit for the timing info. I think the late Pete Little (a beefarmer from Exmoor and a builder of excellent beehives – I have several) determined the 5 days empirically and first published it – to my knowledge – on the Beekeeping Forum. Varroa need to go through a phoretic phase of 4-11 days which I’ve previously discussed to have maximum fecundity. I’d probably favour four days rather than 5 as I think OA quite rapidly loses activity … but this is based on precious little evidence to be honest.

      You could probably ‘model’ phoretic mite numbers, mite emergence rates and all sorts of other things in the hive using software like BEEHAVE, and use that to determine the optimum treatment regimen. However, it’ll be influenced by the laying rate of the queen (which determines the number of available late-stage larvae for infestation), the mite load, the size and activity of the hive i.e. you can ‘model’ it but how much similarity the model would have to real life is unclear.

      Or you could do what Pete did … he treated some hives every 4 days, some every 5, some every 6 etc., and see what worked best.

      Or use Apivar 😉 Fit and forget (as long as you remember to remove the strips in 10 weeks).

      Cheers
      David

      Reply
  5. Tony Fox

    I have amended my winter bee keeping regime this year.

    I put fondant above cover board in clear plastic containers maybe 500g at a time, this way I can remove highly insulated roof and not disturb bees yet noted rate of consumption and that’s part of my inspection routine.

    For inspections I closely watch the entrances for flights, carnolians plus 6c and buckfast at 10c, on calm dry days. Thermometer in apiary. If they are flying with intent that’s a nectar source found, if maybe the odd bee returns with nectar it’s meaningless but a good sign, if flying in numbers and 50% returning with pollen then for me it’s time to support and I move from fondant to protein slurry put a very slow rate. In Oxfordshire that’s this year 21/2. So I let the bees lead but then come in with support.

    I apply a 42 day rule. That being the number of days to lay and the young bees to become foragers. I time this to coincide with a flow. That’s gets me to early April. Now I know my carnolians go into swarm mode come circa 3rd 4th week April. So I have a good strong build up for splits sometime 1st or 2nd week. But as I use a single box system I put a second national brood on in March. I also note the first date I see drone brood as that helps determine possible or earliest swarming dates. Once a colony has a combined 4 full frames of brood I am happy to start to look at splitting but normally it’s much bigger than that come early April.

    As my splits maybe still in cold weather, I have been using the double sided mesh crown boards. The upper weaker colony gets the benefit of the heat from the larger queen and forager colony below yet remain a separate entity. I think this gives some advantages. This means of 15 strong hives I get a split from each. Not so strong hives maybe just get build up time or combined or get brood from stronger hives that are too far ahead. When I get it wrong then any swarm cells I make good use of.

    For an Oxfordshire colony this is pretty good I think. About splitting time I bring in the reserve assets….the swarms, most generously donated by the 80 apiaries (according to beebase register) that are within 3 miles.

    To get a good start I have to get my winter inspections correct, picking up on any corrective actions as the weather allows. This year it was just a few issues of clusters not be under the cover board hole used for fondant.

    Reply
    1. David Post author

      Hello Tony

      That’s very organised. I guess at least some of my activities are not dissimilar, though I’m less aware of the timing (other than it’s about two months later in the year due to the differences in climate between Scotland and Oxfordshire 🙁 ).

      I’m going to discuss fondant next week and pollen patties sometime later in the spring (though they’re already ready and waiting in the freezer).

      I’ve been keeping a note of temperatures and flying and have set up a weather station in the apiary. My black bees are pretty hardy but they’ve barely been out for the last month due to the wind and the rain (and consistently low temperatures).

      I don’t think we’d see your Buckfast’s until mid-May and they’d be all tucked up again by late July 😉

      Cheers
      David

      PS Assuming you’ve got the same access to Beebase as I have then the ‘apiaries within’ radius they quote is 10 km. Of course, most swarms move less than a kilometre

      Reply
    1. David Post author

      Hi Tony … assuming average hive numbers per apiary of 5, then 80 apiaries on Beebase still mean there are probably over 30 hives within 3 km. Ample opportunity to collect swarms 🙂

      Reply
    1. David Post author

      Hi Deborah … the search facility should help and you can sign-up for emails when I publish new posts. Delighted you enjoyed the post.
      Cheers
      David

      Reply
  6. Frazer

    I’ve been reading and re-reading your post Tony and appreciate your observations and thoroughness.
    WRT ” flying in numbers and 50% returning with pollen then for me it’s time to support and I move from fondant to protein ” I once read that when bees feed from provisions given above the crownboard, they treat it as foraging from outwith the hive. This could (in nature) be field foraging or robbing. but in any event, I do wonder if the provision of regular protein supplement above the crownboard helps to encourage our bees to continue brood rearing without setback, such as that caused by Spring 2021 when there was a prolonged period of cold weather.
    i’ve often wondered how American beekeepers, enen in more temperate regions of their continent can have strong hives so quickly compared to us. I wonder if there Spring is a more predictable warmer weather, rather than our less predictable maritime climate, which adds weight to protein feeding above the crownboard too.

    Thx to you too again, David, for sharing these thoughts….

    Reply
  7. Helen

    As always an excellent article. Re the different mite drops in the equally treated colonies- could it be that the colony with the higher drop is more effective at grooming ?

    Reply
    1. David Post author

      Hi Helen

      Possibly, but the mite drop when I treated with OA was also high, so I know the level of infestation was also higher as well (perhaps, see below). A percentage always escape treatment – perhaps 5-10% – and these would then reproduce in the early brood being reared by the colony. There are too many variables to be sure:

      • they could be equally good at grooming, but just have a much higher level of infestation.
      • there may be differences in the level of sealed brood (and therefore phoretic mites) and the rate at which that brood has been reared (and emerged), all of which will influence mite drop.
      • or I might be completely wrong about the initial level of infestation (perhaps there was some sealed brood in one when I treated) and it’s actually the same but one colony is really 50 times better at allogrooming.

      Too little information to discriminate between these things … so the best thing to do is make a note in the hive records and keep an eye on things as the season develops. The mite tray will go back in late March/early April and we’ll see what falls out before the first hive inspection later that month. Then we’ll know the brood levels and can try and work out what’s going on.

      We can measure these things … but it can still leave us me guessing 😉

      Cheers
      David

      Reply
  8. Archie McLellan

    Hi David
    This year I’ve left the Correx boards in place under mesh all winter for the first time. I’ve valued the info gleaned from examining the debris every few weeks when I’ve been to the hives. I’m quite admiring of how clean your boards – and bees – are, though perhaps not al the dirt on mine has come from above! Some of the boards are definitely not a good fit.
    The other reason I’ve left the boards in place this year is a bit of sitting on the fence. I’ve noticed that people who build their own floors now (particularly people making floors with under floor entrances) are also sitting on the fence on the issue of solid vs open mesh floors, and are dividing the floor 50:50 between solid boards and mesh. So the other reason I’ve been leaving Correx boards in place is to slightly reducing the exposure to the elements you get with full OMFs.
    It’s difficult to know anything for sure. I’m not surprised we sit on the fence when we can!
    Thanks as always for the post.

    Reply
    1. David Post author

      Hi Archie

      It’s noticeable that colonies in an apparently similar location and of broadly similar strength often show very different patterns on the bottom boards. I had one in the shed that had lots of legs and antennae on it. The adjacent colony had none. Weird. Both have identical floors with tight fitting boards.

      All those boards in the post above were in for about a month. They’re now all out again. I’ve got no solid floors (other than those on bait hives) but haven’t noticed any difference in overwintering survival or strength whether the boards are left in or not. However, note that the sample size is almost certainly far too small to see anything other than a gross difference in survival rate.

      It’s been a really mild winter up here with only one frost in the last month. There’s still a few weeks to go yet though … 🙁

      Cheers
      David

      Reply
  9. Julia

    Hi David,
    I started keeping bees in South Bucks last year after completing a course. My small colony is still alive I’m happy to say. I’m mindful not to interfere with them aside from checking the fondant level.
    I really enjoyed your post and look forward to reading more of them.
    Thank you.

    Reply
    1. David Post author

      Hi Julia

      I’m going to discuss colony stores next this week. The danger period isn’t over yet for winter survival, but it’s only a few more weeks to go (and fewer for you in Buckinghamshire than for us here in Scotland).

      Delighted you enjoyed the post (there are lots of others to read while you’re waiting for something this Friday. Have a good season.
      Cheers
      David

      Reply
  10. Graham

    Hi David

    I really enjoy your articles, but this one had me in stitches (I have a warped sense of humor!!) You wrote “Use the phone on your camera to take a quick photo (you’ll need to use the flash).” My camera doesn’t have a phone so I couldn’t call to ask if the entrance was clear.

    Keep up the brilliant articles.

    Cheers
    Graham

    Reply
    1. David Post author

      Hi Graham

      Pleased you enjoy the posts 🙂 . Is ‘the phone on your camera’ an example of an anastrophe? I suspect it might be … alternatively, although not a catastrophe, perhaps it just reflects the fact that it was written very late at night. Most readers either; 1) missed it entirely, 2) hadn’t bothered reading that far, 3) just assumed it was yet another example of my garbled writing, or 4) missed the joke entirely.

      Of course – and this makes me sound like a right old fart – most young(er) people these days use their phone primarily as a camera (and texting device) and almost never as a phone. So perhaps what I wrote was accurate after all.

      Cheers
      David

      Reply
  11. Duncan Philps-Tate

    Hi David
    As always a fascinating article.
    Somewhere close to the start (which I now can’t find) made me wonder how much the bees “wander” from the cluster to reach stores. I don’t think I’ve ever seen this discussed and mostly I’m terrified by the dire tales of “starving centimetres from plenty”. Are you able to shed any light on this? In particular, do they move across the box perpendicular to the frames at all, and how do they know where to head? (Though maybe I mean do they go through the wax or round the end of the frame?)

    Reply
    1. David Post author

      Hello Duncan

      I don’t know the answer, but I’m happy to speculate … I suspect the cluster stays in pretty close contact with stores if it can. You could imagine the edge of the cluster eating the stores and then ‘moving into’ the vacated space. The rest of the cluster would then have to shift across the frames accordingly. All this will be influenced by the presence of brood which will ‘anchor’ parts of the cluster. Since the cluster is a sphere (more of less) sliced through by the stores-laden frames they presumably move between the frames i.e. along the seams between the frames, more easily than perpendicular to the frames. Again, this will be influenced by the potential cooling effect of the sidewalls of the hive, which may restrict lateral movement.

      All of the above is wild, and largely uninformed, guesswork 😉

      But there’s one final point that is important. The winter cluster is more-or-less constantly shrinking in size as the winter bees slowly die off. If the bees die off fast – for example because they have high levels of DWV which is known to reduce the longevity of winter bees – then the cluster will get smaller a lot more quickly. These are the conditions you see ‘isolation starvation’, with a pathetically small cluster of bees just a few centimetres away from their stores.

      Yes, they may have starved to death … but they starved because of DWV (and Varroa). I would not be surprised if the majority of isolation starvation is actually due to Varroa and DWV … and therefore avoidable by appropriate mite control.

      I really ought to write a post about this …

      Cheers
      David

      Reply

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