Challenging a good theory

Hard to believe we've had out beepol lodge almost a week! So, it's time for an update. 

It's been a week of cold and changeable weather, so the first few days in particular were not very active. Moreover, our plastic lid was still trapped (loose) inside the nest and we think it was possibly impeding the bumbles a bit from freely leaving the nest. Plus they had to recover from their travel trauma. 

By the weekend I'd cleared the lid and we definitely had some new first flights occuring. That enabled me to calibrate the motion detect on the CCTV and make sure all the tech was working properly. The weather was still a mixture of wet and windy and very cold at night, so we weren't surprised to see much happening, though it was certainly noisy and busy inside the nest itself.

The down-facing camera gives us a great, sharp view and good audio too; so this year I'll be taking some recordings and doing some frequency analysis. 

Monday on the other hand was a different kettle of fish, with a hive of activity - if you don't mind me mixing my metaphors and literals. This was the day that our new borns really decided to go for it. One after the other, time and time after time - almost a stream of babies coming out on their first flight - at times it seemed like one a minute. And returing with pollen too - greyish yellow by the look of it. It was amazing to see them all so busy and carrying out their programming! (incuding their first memorisation flights). 

Two babies - one about to leave, one just performing her first memorisation flight, looking at the nest (top left)

A few were nervous - not sure about pushing on the flap, or not sure about launching off the nest ledge, and either coming back in from flight after 10 seconds or just going back in the nest. A few were not sure about the nest - returning with pollen and then heading back outside with it, before realising the inside was definitely where they were meant to be. 

Some of the tiniest didn't seem to figure out the nest entrace at all - even though it was wedged open - instead scratching at the connecting gap on top of the new wax-protection module. Had they forgotten where they came out? Was their eyesight not so good? Or was the smell of the nest stronger from there? As ever, each observation leads to many questions. 

Here are a few more observations:

A night time we sometimes have a solitary bumblebee standing guard on the front wall of the lodge, here's one tonight - she's been there several hours: 

standing guard over nightUsing our cunning reflective size guide, we can say she is about 12mm long. 

She is by no means the smallest or largest bee in the colony. I've seen one I estimate at about 8mm and have been seeing several large ones tonight. I'm not sure if the largest of these is the queen or not: we'd love to see her. Certainly there is a large bumblebee that moves slower than the others and is seen occasionally doing a tour of the area under the camera. It's her combined size and (slow) speed that makes her stand out. At one point this particular bee paused for a while over the wax pots we can see - was she laying?  I'd love to see that - see what the process is - how and when she lays and how the other bees (presumably) seal the pot. 

This is a very big bumblebee - slightly side on - in the centre of this picture:

could this be our elusive queen?

And look at this tail end at the top of this picture. It's massive - at least twice or thrice the size/width of any of the others:

Or is this our queen's tail?

We think we saw our active queen only once in our Koppert box, this time last year, so we are not sure what her behaviour patterns are and how much of the nest she uses. We think this is probably a good spot though - directly under the infrared heat from the camera - so I wouldn't be surprised if se was to lay something near here. 

Honeypots 

It's a bit of an unintended, but delightful, consequence that the infrared from the camera is providing "catchlights" in the wax pots that contain liquid honey, as this gives us an easy way to identify and count the honey pots over a fixed area. Our friends from Dragonfli posed the question about how the stores get used and we are keen to understand this too. 

This morning when I first looked I could identify 4 - and 90 minutes later only 3. I wondered if one had been consumed giving the inclement weather and lack of foraging activty (very windy this morning). By this evening there were 7 indetifiable catchlights. So, not only had it been apparently refilled, but others made too. 

In the final analysis, however, I think the pot from 9am this morning that seemed to have been consumed was just slightly obscured by a bee - or at least the line of the reflective light was - and so I don't think this pot got used. However, I have seen one bumblebee apparently drinking some honey tonight (not much) but more interestingly another bee spending a good deal of time during the day actually resting over the pot and covering it. 

You can see this top left in the following picture, where the pot at "11 o clock" is obscured. This bee had its belly over the pot, hanging face down over the side (as I write it's doing exactly the same again). I'd love to uncover an explanation for this - it might just be coincidence - i.e. the spot it likes to rest - but one thing that is clear from looking at these pictures is that even with a time gap in between, it (or a sister) has come back and chosen exactly the same spot. 

bumblebee hanging over honey pot at "11 o clock"

Quiet in the night

Another thing we have noticed after the first few evenings of real activity is that night times have become a lot calmer and quieter. At first there was constant activity under the "down" camera almost 24x7, but again, as I look tonight, it's quiet. A few bees are in view resting, but only occasionally does one mooch past. They are resting and keeping warm. There is occasional buzz from a single bee and something we really want to do it uncover any patterns in the sound.

We sometimes hear sustained buzzing from a single bee (occasionally a second) in longish bursts. The we sometimes hear a high pitch squeak in short repetitions of about 1 per second. We wonder if this is associated with hatching?

Certainly the bees can be silent when they choose - as they are doing so tonight - with just the occasional high pitched buzz from somewhere unknown. If we can establish a link between bee size and pitch, then we can start to gauge what size bees are making the sound. Intuitively it seems that small callows trying to emerge from a pot might make a high pitched buzz, but it's pure hypothesis at this stage and remains to be tested/observed. To that end we are recording some of the sound patterns from the nest. 

The change in sound during the day poses the question why?

Certainly when threatened a co-ordinated "fizz" seems designed to ward attackers off and possibly communicate the threat throughout the nest colony. Some noise may be due to fanning - keeping the nest cool. Some of it, of course, may be vibrating to keep the nest warm - although perhaps we'd expect more of that during the night time rather than the day - so that is not a convincing explanation.

So - the question remains, is some of the sound associated with communication? Prevailing theory is no, but we love to challenge a good theory!

The Physical Exam

It's 3 weeks since we saw the last activity in our Beepol nest and 2 weeks since I took advantage of help from my brother to dismantle the nest and lodge and photograph it.

It was really quite an interesting experience and much more pleasant than dismantling the Koppert box we had earlier in the season. That box was infested with wax moth and was in a fairly unpleasant state. In contrast the Beepol box was uninfested and fully intact, complete with all evidence of several colonies having existed (as we observed).

As we lifted the lid of the lodge there was a pleasant (though faded) smell of honey, mingled with the typically waxy odour. We could immediately see just how high the bedding had been raised since it was first added: underneath was a complete substructure of wax pots and pillars and the ceiling layer of bedding had been lined with a thin layer of wax too.

Peeling back the ceiling revealed a tall, compact cluster of we pots built by our last (third) queen. As expected, these pots were nearly all quite small and less well developed due the the September, October and November temperatures.

waxpots, still with honey; some still sealed; pollen in the background

Most of them had hatched, which of course accounted for all those tiny bumblebees we saw and rescued and surprisingly, only one or two were unhatched. You can see a small, prominent, fully intact wax pot in the pictures. Many of the dead bees In the box were very small too, again, part of the overall pattern.

The distinction between 'levels' in the box was very prominent too. The original colony had suffered heat damage at the base of the nest and the wax was a darker brown colour and more roughly textured. It was very buried below the added bedding and a whole new upper layer of fresher, more yellow wax from the subsequent colony. There was no doubt at (at least) two distinct colonies developed in the nest.

undeveloped bumblebee eggs in a wax pot

We also tried to find the 3 queens we expected to be in the box - and we did indeed find 3 larger bumblebees although they looked surprisingly shrunken and reduced in size in their still and curled up unfuzzy state, to the extent I would have struggled to perhaps recognise them as queens if I hadn't already known they should be in there. [The backstory: The original 'mother' queen had come out of the nest to die, but one of her brood had stayed on permanently and started brooding. She seemed to get to weak or too large to leave the nest and died inside. But another 3 queens also turned up in succession and two of those seemed to brood. We did of course rescue last one of these and she died in our care, but the other two also died in the nest.]

Something that was completely new to me in this nest was a number of wax pots broken open with a white sticky substance in them. In some pots it looked like a solid mass, but in others was quite clearly composed of smaller lumps and 'clumps'. It seemed these would be eggs or early larvae of some kind, but what I wasn't sure was whether this was from a moth (we'd seen one or two in the nest) or flies (also seen inside). I turned to my expert at Dragonfli, suppliers of the Beepol nest, and he confirmed this appeared to be bumblebee eggs. Until now I had assumed that only one egg was laid per wax pot, but he confirmed that actually they do lay half a dozen to a dozen eggs in a pot then seal them in with some pollen..

There were quite a number of pots in this condition, symptomatic of a very busy queen who was struggling against the odds to get a brood to develop to critical mass. Sadly she never made it because her offspring could just not develop successfully in the cold temperatures of October and November. She kept trying day after day, and indeed, pretty much died trying - but it could never be.

So, this represents the end of the 2011 season, although the work is not complete as we clear up and decommission our setup (nest. CCTV etc), write it all up and then begin to prepare for the 2012 season.

Finally, a picture of a developing larvae as it starts to reach the callow stage. I removed her from a sealed wax pot. You can see the wings are not quite developed yet and the usual white down actually has a warm golden colour. Whilst sad, for me there is something starkly beautiful about this picture... 

Apian Autopsy

On Saturday 16th July we declared our Bombus Terrestris Bumblebee Hive (our first) closed for business. It had been dormant for 3 days; sadly silent, inevitably inactive.

In total it survived for 10 weeks (10 - 12 weeks being the stated life) - although during the last two weeks their was a steady decline from activity almost every 30 seconds, to once every 30 minutes, to a handful of events per day. It was very sad to see this happening, knowing that - although inevitable - something didn't seem right, and what was already a short enough life seemed shorter than it should have been. 

Koppert Box

The nestbox/hive was a commercial hive from Koppert. It consists of a carefully designed plastic "tub" insided a protective cardboard box. "Tub" is a bit of a dis-service to the main nest box actually. In fact, it is a carefully and beautifully designed space for the bees to nest, with

• a large supply of sugar water
• all the nesting material they need
• pollen to get started
• a two-way exit/entrance and a one-way entrance
• a built-in "shutter" to control the entrances
• carefully designed ventilation system

koppert box removed from shelter

Preparation

We allowed for the fact there might still be some live bees in the box. To that end we prepared one of our wooden nest boxes with nest material and food supplies so that we could transfer any surviving bees to a new home. we also bought some cheap kitchen tools for scraping and grabbing; they were very low cost so that we could dispose of them afterwards if they could not be satisfactorily cleaned. 

table prepared for examination and transfer of live beesWe also kept all the video cameras on the CCTV system running in case anything interesting happened. There is one inside the Natupol box, one inside the wooden box and one on the table.

Opening the box

It was difficult to get the cardboard lid off the box - we discovered this was due to the sticky silky fibres of wax moth that had invaded the nest. We had suspected this had happened, leading to premature failure of the colony; and I had seen evidence of moths inside the hive on the CCTV on a few occasions. 

This video gives you a good idea of what the inside of the box was like when we opened it up. 

There were no live bees in the box. Below are the other main things we observed

Wax Moth

 The wax moth larvae (catepillars) are self-evident on the video. Their cocoons and trails are extremely sticky and tough and it was very hard to get the box lid off (we ripped it) and remove their cocoons from the inside of the box. We were veyr disappointed to find them inside the nest, though took some comfort from the fact it was not totally destroyed within. Indeed, most of the wax and a good deal of honey was intact and the wax moth larvae were concentrated in two places: top left of the box (near the CCTV camera) and underneath the heart of the nest, embedded into the polystyrene insulation. 

This does beg the question whether our infra-red internal camera might have encouraged the wax moth and provided better conditions for growth (the latter almost certainly being the case). I need to do more research to conclude whether it is safe to have the infra-red camera inside the nest. (The bees, by the way, are not adversely affected by it). 

Wax Pots / Honey Pots

I was quite surprised to see the vast quantity of wax pots intact within the nest, having expected the wax moth larvae to have consumed it and for that to have then explained the rapid decline of the colony.  As you can see from the pictures, this was not the case - and indeed, there was a sizeable reserve of honey. 

Theories, then, for the decline of the colony would include possible desertion (which I believe I have evidence for on CCTV) and dysfunction of the nest caused by the wax moth silk - e.g. preventing bees from hatching and moving freely about the nest. 

Corners

Something we observed during the life of our nest was bees assembling in the corner under the camera to die. We wondered if it was coincidence or a true pattern. We discovered it was indeed  a pattern - firstly, here is a video from earlier in the season where we saw one bee dragging another one to this corner:

We saw this behaviour repeated on the CCTV. When we came to open the box we found this in two corners:

 dead bees in box cornerYou can see that a large number of bees have collected in the corner - two corners were like this, the other two clear. They were also rather "charred" - although one corner was under the IR cam, the other was not, so my theory is actually that this is also where they go to the toilet (certainly the remnants on the box suggested so) and that there has been a chemical reaction (which is what happens with manure in a compost heap). Other than those bees that never emerged from their pots, there were very few dead in amongst the nest, which suggests the bees act like "good citizens" and organise themselves a "graveyard" to die in. I find that amazing. 

Unhatched Bees

One of the more upsetting aspects of our discovery was the unhatched bees. With wax-moth silk threaded and webbed through the wax pots, they were very constricted and at first we thought this probably accounted for the apparent high mortality rate amongst hatchlings. However, after thinking about it some more and photographing the wax pots that were salvageable, I was struck by the number of them that had been broken open and had developing bees inside. I concluded that this may well have been part of the damage the wax moth created and would explain why many didn't hatch perhaps.

It's both fascinating and sad to see partly-developed bees in the wax pots, curled up and forever asleep. 

 Very noticeable are the white, downy strands of hair that cover them. we didn't find any that were very small, like Holly, who was the most incredible survivor. Apparently temperature, if insufficient, stunts growth: Holly was born very early on and perhaps in the young nest the temperature was not so high. All of the bees I observed during this examination were well developed in size, if not fully developed in features. 

Is that Fifi?

FIfi was our Queen Bee, named by my niece; but of course we never got to see Fifi as she was delivered in the box and stayed in the box throughout her life - all this work as an unsung heroine! We think we may have seen her once or twice on the CCTV camera traversing the corner of the box, though it was very hard to tell.  we are reasonably confident this is her in the middle of the picture as this is the biggest bee we found; you can see she is markedly larger than all the others. 

The remains of Fifi

Next steps

There were no live bees in the box, so we took the opportunity to take it fully apart, destroy all wax moth larvae as best we could and then clean everything later using detergent and a jetwasher to blast everything clean. Of course, we also took photos and I preserved some of the recoverable bees and wax pots to photograph more closely (as per the pictures of the unhatched bees above). This is our surviving record of our colony.

We will keep the Koppert box. Not only is it a wonderful piece of design, but it's also a high-performance nest space! As a minimum we'll have it as a spare for next year, in case we have to transfer the nest out of its host Koppert box for some reason. We can also use it for educational purposes, and possible even try and get a queen to hibernate in it over the winter.

so, in fact, this is by no means the end of the road, rather just the next phase: devising and developing better nest systems, better moth protection and encouraging queens to hibernate. And not just that, we're also getting a beepol box (in a few days, at the time of writing), more of that in the next post.

There is no rest for the busy Bumble-keeper - we are all busy bees!!

Wax Moth: Killer in the Night

On Saturday July 16th we finally turned off our cameras and declared our bumblebee nest inactive. We'd seen no bee action in or around it for 3 full days, apart from one large bee leaving, that looked large enough to possibly be a queen. A sad moment, given all the time and energy invested into our Bumblebees, but certainly not the end of our journey - still much to do. 

I will consign a fuller write up of the our findings from our examination of the box to a later blog post, but for now just a few words on Wax Moth.

Wax Moth is a Bumblebee parasite, a fact we were not aware of until the last few weeks of the function of our nest. It seems that honey beekeepers are well aware of the existence and precautions required against the wax moth; knowledge that perhaps doesn't extend readily down to the novice Bumblebee hobbyist; indeed, all the information I've found online is directed towards honeybee keepers. 

The bottom line is this: the wax moth spends time checking out the nest and even staying close to pick up the scent from the nest. Then it enters the nest secretively with the aim of laying its eggs without being discovered. The moth larvae build these incredible "silky" channels and tunnels to move around  the nest in. It's like a whole underground network made of really tough and sticky silky fibrous material. This protects them from being attacked by the bees. Then they basically munch their way through the wax pots made by the bees until the colony can no longer survive. 

According to experts at the Bumblebee Conservation Trust, it is thought that up to 80% of garden-sited bumblee nests succumb to the wax moth. Some of the reasons stated for this being so high include the general garden habitat, which appeals to the moth and also that garden bumble bee nests are generally much more conspicuous (compared to say, a small hole in a mossy bank on the edge of field). I'm not 100% convinced the latter is a good explanation, or at least interpretation (it suggests that the moths are able to discern which man-made constructions comprise bumblebee nests); my personal feeling is that Bumblebees and their nests are more conspicuous in a garden simply by nature of the confined space and land area that is occupied. Add to this the other man-made features which may attract the moths, such as lighting,  and what you find is bees and moths habiting (say) the same 100m-square area: basically, dinner on a plate for the moth.

We may have unwittingly contributed to this situation ourselves by having solar lighting in the garden and infra-red lighting on our CCTV cameras. Once in a while we saw a moth at the mouth of the nestbox and wondered whether the infra-red had attracted it there. The jury is still out for me on that one - because what we didn't see was sustained activity around the camera, which I would have expected if the theory was true. 

However, there is another side to the story. When we opened up the Koppert Hive (which proved extremely difficult to do) we discovered that the wax moth larvae in the upper section of the box all eminated from around where our internal camera was sited (poking through the box lid). This left us wondering whether the heat/infrared from the camera had provided an attraction to the moth/larvae and a preferred environment for it to develop. At this stage I need to do more research/reading to be able to answer. 

 wax moth larvae and cocoons extending down the box side near the infrared camera

In a sense then, I was paradoxically relieved to discover that there had also been significant larvae development at the base of the box, underneath the whole nest. Perhaps, again, this leads to a theory of warmth being desirable, but it does suggest that it was not the camera and camera alone that provided an environment for the moth development. 

 Wax moth larvae in the base of the box, embedded in the polystyrene

Their invasion on the nest is really rather horrible. The larvae are bright yellow/green, up to 2cm long and fast movers. (There are lots of pictures on the web, so I didn't take any close ups to publish here). They hide out in their silk cocoons, which are dense and sticky (and why the box lid was so hard to remove; we almost had to rip it off). They seemed to have built a vast structure of cocoon tunnels to hide in around the edges of the box, away from the core of the nest itself, but these then extend into the nest/wax pot area in a web of silk paths and make the whole structure one very sticky and matted mess of silk, wax, honey and pollen. It seems to me it's possible this is responsible for restricting the movement and hatching of bees within the body of the nest structure, which aside from the destroying the wax itself, may also contribute to the nest decline. 

I was very sad to discover our box had been invaded by wax moth - we suspected it around mid June after a decline in audio activity from the nest, before a slight reduction in visible activity. By the beginning of July I was 99% certain - at one point we did see a moth inside the box on the CCTV, although we didn't see the larvae. Then the rapid decline began over the first 10 days of July, and I was sure. I was more sure than a sure thing from Sure Street, Sureland when on the final day I could see the larvae actually moving around on the nest bedding on the CCTV. Pretty gross actually. I'd like to try and go back over the CCTV if I have time to try and figure out when the initial invasion happened. 

I was gutted that we were powerless to help - or at least seemed so at the time, the Koppert box being a sealed unit. But in fact, having now disassembled it, that is not the case, (it's just cleverly constructed and clipped together) and it may have been possible to intervene earlier if we had really been sure of what was going.

This was partly down to lack of visibility inside the box and partly down to not really knowing about the risks of the wax moth until late in the day. The other lesson I will learn from this, is that it would have paid to have checked the nestbox all round from time to time. We believed the best thing was to leave it as alone as possible in its shelter and avoid stressing the bees by moving, examining and even opening it . But in hindsight, this might actually have paid off if we'd seen evidence of intrusion round the back of the box where the camera was. Although, to be fair, once the damage had got to the stage where it was visible, it may have been too late.

For next year we will try some strategies to try and reduce the risk of wax moth invasion:

• Seal all the ventilation holes around the nest box by sticking on small webbing (as used on our wooden box to prevent Ant intrusion)
• Eliminate lighting (or at least any nearby) in the garden
• Control the opening of the nest box using a wireless timer (also available from Koppert)
• reduce usage of the infrared camera, certainly inside the box
• use "Certan" treatment around the box
• plant some mint, which may help to discourage them

I would actually like to some research at this stage with what's left over from our box. We could use the wax pots that are left over (substantial quantity) to both track the rate at which the larvae can destroy it, but also potentially assess the effects of the above strategies - for example, whether the infrared attracts the moth and encourages development. The only thing is, we don't really want to end up creating a whole colony of new moths which could go on to destroy other bumble nests or come back next year to destroy ours. So, for the timebeing, we are still contemplating this.

But one thing is clear for next year: whatever we do, we have to try and prevent this devastating killer getting near our nest.