Hive Monitoring - Surprising winter data

[boywonder]

Hi all, thoughts on this are appreciated. Attached is a video taken at the entrance of my Warre hive today, before the storm. It being mild, the bees were out on (presumably cleansing) flights, and some corpses were being ejected. So all fairly positive, and, for now at least, it appears the colony is still OK.

The hive scales are showing a progressive decline; though 2.5kg in the last 3 months must certainly rank as a frugal use of stores. Maybe the colony is very small.

What I can't quite wrap my head around is what happened to the internal hive temperature (and humidity) in mid September, and how this data has tracked since. Indeed I both changed the battery, and then sent the sensor unit back to Slovenia, as I believed it to be defective.

I started monitoring in April last year, at a point when the colony was clearly expanding. As you can see, come rain or shine, the bees kept the hive temperature at around a constant 35 degrees, and the humidity at about 65%. Then, in mid-Sep, a dramatic collapse:



Even though I had healthy cohorts of flying bees, my initial conclusion was a catastrophic event (probably a Queen death) causing the colony to lose it's cohesion. As such (and assuming a functional monitor), I was expecting a speedy demise.

Instead, these bees are showing consistent signs of life, even though my monitor has even shown (last week) internal temperatures dropping below zero:



Whaaat ??

We will all be familiar with feeling the strong heat emanating from a crownboard in, say, February/March, when the brood factory is firing up again in anger.... But (mainly as I don't open my hives at this time of year) I have no real 'feel' for how much heat is emitted/lost by a colony in cluster.

By all accounts, if my stats are to be believed - virtually none. i.e. the cluster is staggeringly efficient.

The hive has 3 boxes on, incidentally, and the sensors are between the top box (which, in Sep, contained stores, but no brood) and the middle box (which contained brood in all stages).

I fully respect the "insulationladz" on the forum, and the use of a 'perfect' tree cavity as a point of reference for the 'ideal' (with its thick, insulative walls and small entrance)....... I'm not suggesting where they can stick their R or U values, but I would hazard a guess that the majority of feral colonies overwinter in sub-optimal homes, and therefore, whilst it is obviously goodly, kind and right to provide bees dry homes with super-insulative properties, I think healthy bees are well adapted and able to cope even in very harsh circumstances.

Now, these bees might not survive. If they do, I'm going to be very interested to see whether and when the internal temperature clicks back up to the 35 degree level.

It just seems weird to me at present.

Maybe others who monitor see similar things, or not?

Video:

View attachment 1000005262.mp4

 

[WoodenBeam]

Not able to comment on your monitoring situation but having done the rounds recently 20% of my colonies now have a slab of fondant on which is considerably more than in the last few years.

 

[drex]

The bees only keep the brood at 35 degrees. The heat in the rest of the hive is what spills out from that.
The temp you record will all depend on the position of brood or winter cluster and position of the sensor

 

[elainemary]

I think there’s a simply explanation of a temporary brood break in mid September. This often happens with my colonies - remember the annual population / brood rearing curve?
This would explain a drop in humidity as less feeding going on. Brood needs temperatures of 35c and can drop 10c to 25c when broodless

 

[boywonder]

I think there’s a simply explanation of a temporary brood break in mid September

... In which case, that would mean since mid-September (until now), which is at odds with other colonies which, due to the mild winter, have continued rearing brood through much of the winter....

... And whilst I appreciate the 34/35 degree figure being that at which the bees need to maintain brood, it is also the case that, in cluster, whilst the bees in the mantle can get pretty cold, the bees in the core are toasty.

See e.g. The winter cluster - The Apiarist

David explains that bees at <5.5 degrees become comatose, and that the core remains around the 34 degree mark (unless when broodless, when it can be as low as 18 degrees).

So, a little bundle of warmth, whichever way you spin it.

If you accept that my sensor is likely to be positioned above and in the vicinity of the cluster, and furthermore, that the ambient temperature inside a hive with a closed floor is always going to be a couple of degrees above the outside temperature, then the fact that the internal temperature is pretty much tracking the outside temperature (so even at -7 ish, the air near the cluster is at -2) feels odd.

If true, it certainly shows how incredibly efficient the cluster is at retaining heat, given that almost none appears to being lost/emitted.

 

[abeille]

I'd the sensor is not in the cluster, then all you are measuring is the poor quality insulation properties of your hive.

I don't know where you come up with the notion that fetral colonies live in suboptimal conditions. Studies have shown a swarm makes the right decisions on potential homes in excess of 95% of the time.

 

[Antipodes]

I'd the sensor is not in the cluster, then all you are measuring is the poor quality insulation properties of your hive.

I don't know where you come up with the notion that fetral colonies live in suboptimal conditions. Studies have shown a swarm makes the right decisions on potential homes in excess of 95% of the time.

It's the survival of at least some of the 5% that's interesting. I know of a colony here in Australia that lives on a spindly branch of a tree and has done so for years) with just the thinnest of cover from rain where the branch goes over some of it, yet it hasn't died and builds up each spring and summer with comb extending outwards in great plates. Last year it would have had about 750mm of rain on it through the year...some very, very heavy. Gale force tearing winds. Fantastic really.
I was watching a large cluster of bees on the outside of a hive last week. They were randomly positioned and scurrying about busying themselves. Then it started raining. They turned their heads upwards, gathering together and positioning themselves like shingles on a roof. Not long after the rain stopped and they spread out again, completely unaffected it seemed.

 

[robmort]

Yes the temperature measurement means little if the sensor isn't close to the cluster and the hive isn't well insulated.

 

[JohnRB]

I use the same system - in Winter if the bees move even a little away from the sensor it often reads close to ambient. The first time this happened to me I was quite surprised as I'd assumed there would be a bit of heat in the box, even away from the cluster, but it seems not. In the summer, with a large colony filling the box, the readings are a much better reflection of what is happening. In the Winter not so much. At least when the cluster moves close to the sensor occasionally you know they are still alive.

 

[Parsonage Bees]

Soon after I started beekeeping I've wanted one of these sensors, wanting to know what's going on in there. Maybe they just create more questions.

The internal humidity goes up not long after the temperature drops. Nectar coming in and water content reduced, cluster moves down away from the sensor? As they eat their way back up again maybe you'll see that brood temperature again.

. . . . Ben

 

[boywonder]

I use the same system - in Winter if the bees move even a little away from the sensor it often reads close to ambient. The first time this happened to me I was quite surprised as I'd assumed there would be a bit of heat in the box, even away from the cluster, but it seems not. In the summer, with a large colony filling the box, the readings are a much better reflection of what is happening. In the Winter not so much. At least when the cluster moves close to the sensor occasionally you know they are still alive.

Insightful! Thanks

 

[boywonder]

I'd the sensor is not in the cluster, then all you are measuring is the poor quality insulation properties of your hive.

To some degree I have to take that as being a fact.

This is a well sealed wooden hive with 22mm walls, a solid floor and a small entrance, and as you identify (irrespective of bees) the internal temperature is tracking the external temperature, so implies only limited insulative benefit accruing from the hive fabric.

It makes me wonder whether (irrespective of bees) my Abelo poly hives, with larger entrances and open mesh floors would track similarly. Of course, they would, with no bees.

The variable is the bees. When the bees are generating heat, the poly will retain it better, ( as also, when the sun is beating down, it will better protect the hive).

If a cluster is as efficient as heat retention as I suspect it is, then it (super-anally insulated vs. poorly insulated) probably makes very little difference to survival rates.

To me, the difference, which I routinely observe, is that super-insulated bees a) brood for longer, b) cluster less, c) consume more stores and d) begin to expand earlier.

Not all of those are conducive to survival.

I'd love to know where you get your 95% stat from, BTW. It's not something I have picked up in my own reading. Some feral colonies of which I am aware around here have made bad choices, for sure.

 

[Sutty]

I'd love to know where you get your 95% stat from, BTW. It's not something I have picked up in my own reading. Some feral colonies of which I am aware around here have made bad choices, for sure.

You can only know that if you know they had better alternatives of course!

 

[abeille]

You can only know that if you know they had better alternatives of course!

Thomas d sealy, lives of honey bees, study done by a US University on a controlled island.

 

[abeille]

To some degree I have to take that as being a fact.

This is a well sealed wooden hive with 22mm walls, a solid floor and a small entrance, and as you identify (irrespective of bees) the internal temperature is tracking the external temperature, so implies only limited insulative benefit accruing from the hive fabric.

It makes me wonder whether (irrespective of bees) my Abelo poly hives, with larger entrances and open mesh floors would track similarly. Of course, they would, with no bees.

The variable is the bees. When the bees are generating heat, the poly will retain it better, ( as also, when the sun is beating down, it will better protect the hive).

If a cluster is as efficient as heat retention as I suspect it is, then it (super-anally insulated vs. poorly insulated) probably makes very little difference to survival rates.

To me, the difference, which I routinely observe, is that super-insulated bees a) brood for longer, b) cluster less, c) consume more stores and d) begin to expand earlier.

Not all of those are conducive to survival.

I'd love to know where you get your 95% stat from, BTW. It's not something I have picked up in my own reading. Some feral colonies of which I am aware around here have made bad choices, for sure.

It's well studied and reported. Read Thomas d sealed, lives of honey bees. He references his PhD studies carried out on controlled islands

 

[jenkinsbrynmair]

It's well studied and reported. Read Thomas d sealed, lives of honey bees. He references his PhD studies carried out on controlled islands

In that case why not refer the OP to 'Honeybee Democracy' or indeed 'the wisdom of the hive' which goes into it in far more detail.
It was just one 'controlled' island - Appledore

 

[Penninetrader]

It's the survival of at least some of the 5% that's interesting. I know of a colony here in Australia that lives on a spindly branch of a tree and has done so for years) with just the thinnest of cover from rain where the branch goes over some of it, yet it hasn't died and builds up each spring and summer with comb extending outwards in great plates. Last year it would have had about 750mm of rain on it through the year...some very, very heavy. Gale force tearing winds. Fantastic really.
I was watching a large cluster of bees on the outside of a hive last week. They were randomly positioned and scurrying about busying themselves. Then it started raining. They turned their heads upwards, gathering together and positioning themselves like shingles on a roof. Not long after the rain stopped and they spread out again, completely unaffected it seemed.

When you think you know it all is when you find out you know nowt. This post of yours was very interesting, the fact that the bees you observed were living literally outside gave you a rare opportunity to see something special. The girls don't reveal all their secrets to just anyone.

 

[boywonder]

In that case why not refer the OP to 'Honeybee Democracy' or indeed 'the wisdom of the hive' which goes into it in far more detail.
It was just one 'controlled' island - Appledore

I've read Honey Bee Democracy cover to cover. Brilliant as it is, illuminating as the studies are (indeed they have informed both my bait hive placement, and my beekeeping more generally), and as amazing as the site selection process is, I do not recall any statistic of "95%" optimal decision making.

I'd be happy to be pointed to the page that's on.

However, even given that, if feral bees are mainly selecting the "optimal" home from choices A, B, and C... but all are variously crap (chimney, stone wall cavity etc..), then just because they may mostly choose the 'best' one (vs. Seeley's identified criteria) it by no means indicates that most end up in ideal conditions.

We don't all live in the vicinity of monumental trees with handy south-facing cavities, 5m from the ground and with small, defensible entrances.

That is not the reality. I still stand by the assertion that a) a large proportion of feral colonies overwinter in thermally sub-optimal conditions, and b) a cluster is an evolved and efficient means of a colony retaining heat.

Anyway, most probably disagree.

I read more about Derek's PhD work in this month's edition of Beecraft. The science is illuminating but not conclusive. Much of it is compelling; however, I find the assertions about the clustering behaviour (and related claims of 'cruelty') to be speculative at best.

 

[jenkinsbrynmair]

That is not the reality. I still stand by the assertion that a) a large proportion of feral colonies overwinter in thermally sub-optimal conditions, and b) a cluster is an evolved and efficient means of a colony retaining heat.

Anyway, most probably disagree.

I bet the majority would agree

 

[abeille]

I bet the majority would agree

Yes, I quite imagine you would.