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. 

67

It's been a quiet weekend (plus a day off work) on the blogging front owing to us have guests; and to a degree also quiet on the bee front for the reasons outlined below.

Special Guest

Our guests were very special - amongst them was my 3yr old niece, Chloe, who named Holly for us. Since the loss of Lucy (Lucas) last week, Holly had changed behaviour. She came out of her nestbox and started sleeping "outdoors" in the tub overnight. And her activity levels had begun to drop. Prior to the arrival of Chloe we were concerned for Holly's wellbeing, desperately hoping she could hang on for wee Chloe to meet and enjoy watching. 

Thankfully Holly clung onto the last, although she became very slow and inactive over the weekend. At one point we had a major scare, when for the first time she managed to get trapped in amongst the stones in the box.

Chloe had the pleasure of seeing her outside of the nestbox (and inside for a short while) over the weekend and walking a little, though most of her time was spent resting under moss. Sadly tonight, though, is her last at the grand old age of 67 days. 67 days of joy, amusement and often bafflement. She's followed the pattern we now recognise - become very still during the day; shaking or moving a little, gradually less and less; unsteady; curled up a little, tongue out; but unable and unwilling to drink anything.

A tiny, stripy ball, barely perceptible below the moss that was keeping her warm and feeling safe. Holly was rescued quite unexpectedly and we had to develop and perfect our techniques and care for her and her siblings on the fly; and she has taken a lot of our attention over the last few months, so she will indeed be missed. After our standard 24 hour minimum confirmation period we will give her a fine burial in the lavender where the next generation of bumblebees will forage next year. 

Holly when she was rescued

Koppert Colony

The other sad news is the final demise of our Koppert Hive in the garden. Over the month we noticed the sound inside the nest changing from a busy buzzing to a crackling sound. We had no real explanation for this at the time, although I now think it was the onset of Wax moth. Over the last week the activity in the box has signifcantly declined to the point where yesterday there was an average of about one "Motion" event every hour - which probably represented at most one or two bees actually active and foraging. 

The Hive has just made it to 10 weeks old - it was quoted as 10 - 12 weeks lifetime, so there is the possibility this is a natural conclusion and not caused by the wax moth. However, there is no denying the fact that not only did I see moths on the CCTV outside the box on occasions, but sadly over the last two days I have seen (at least) one inside the box. This is just such a bad omen. It's very upsetting to think that the colony might have been destroyed by this parasite, whose larvae destroy the waxy honey pots inside the nest and thus destroy its ability to survive. I really hope they have been able to produce new queens before this devastation, but I'm not too hopeful that was indeed the case.

If I'd known about the wax moth when we got the hive I would have taken stringent measures to try and better protect it. As it is, I knew no better. My plan for next year is to find something natural to try and discourage the moth (Mint has been suggested) as well as look at technology solutions. My preferred option at the moment is the wireless entrance controller by Koppert to close the box overnight. 

This is not the end of our project - aside from being sure the colony is fully inactive, there is still some data to collate from the CCTV system and also much writing up to be done. Then there are preparations for next year; I want to design something for queens to hibernate in later in the year. I also want to adapt our nestboxes in various ways. There is quite a lot of photography to sift and organise, and I have several other creative ideas too. It's going to be busy!

Looking for Lucy?

We came downstairs on Wednesday morning and confirmed that, sadly, Lucy had indeed died. She was curled in her "ICU" tub, static and fragile as he had been for the last 12 hours or more. She'd made an amazing recovery two weeks earlier when she looked almost the same, but this time it was final. 

There at the entrance of the nestbox was Holly, adopting the position we have seen other sentinel bees adopt outside: head poking out of the entrance hole; one front foot in, one front foot out. She was checking something. 

A few minutes later she was back in her nestbox, mooching in her moss. The absence of Lucy had caused an immediate change in Holly that was reminiscent of her former behaviour - just sleeping in the moss all day. It was the introduction of the other bees for company that seemed bring Holly out of her shell and adopt a role as head nest Matron and General Floor Scratcher. 

We left her to be, slightly concerned, but thankful she appeared to be as energetic as usual, even if her behaviour pattern was different. An hour or so later when we came to check on her she wasn't in her box at all! There she was, poking round the big tub! This is only the second time it has happened; the first time was a week earlier after LBB had died and Holly came out with Lucy. At the time we wondered whether somehow Lucy had encouraged Holly to come out, but following this latest pattern it looks more like a search for a lost friend. 

I took this video of Holly exploring round the box. It's quite long because it was such a rare opportunity and we don't get a lot of chance to study her or see what patterns she adopts when she's out of the nestbox. 

It was clear she was going to stay in the "outdoors" all day so we made special provision by bring in more lavender and coating it with some honey water. Some of the lavender was wet too, and to our great joy she climbed straight onto it and drank and drank as if she'd just run a marathon. All along we've wanted to make things as natural as possible for all our bees and this was an opportunity to try and teach her something all her siblings absolutely love to do: feast on lavender!

Holly continued to give us a few scares by not going back in her box overnight and managing to hide herself around the tub. This behaviour is concerning because it's in the last few days of life that we've seen the other bees start to change their sleeping pattern. The plastic tube rolling into the centre of the tub was the first consequence of her attempting to push herself into an imaginary cubby hole underneath it. It shocked us when we discovered how far she'd been able to move it - though it probably shocked her more as it set off down the incline! But, she was determined to stay out and burrow into the tube, so in the end we covered her with some moss and to the best of our knowledge she stayed there all night. 

She's been doing the same today - traversing round the box, resting at times. We haven't really seen her drink, which is a worry; but she seems to have lots of energy, even though she now seems to be on a 10 hour day, compared to her previous 24! The important thing is that she has been active rather than burying away for extended periods, as if she has lost interest in being a bee. 

What's most baffling, though, is the complete change. And the fact that it is syncronised with the loss of Lucy. She has a box with infra-red heating that she loved to sleep in, going empty! It seemed as though Holly was looking for Lucy at first - and now that she can't be found, Holly has changed role. She doesn't need to be Matron (or floor-scratcher for that matter). Perhaps she's come out into retirement!

Entitled to an Armchair

Fading

We've seen a steady decline in Lucy (TinyLittlebee) over the last few days and today looks very close to the end.

I wasn't home but BCW administered wonderful care and provided status reports for me. Just as LBB had done before, Lucy became unsteady and uncoordinated and by this evening has become stationary. Perhaps, if you look closely with a magnifying glass there is a little twitch in the back leg. Or maybe it's just air currents. 

She's struggled for the last 24 hours - falling on her back regularly and being unable to right herself. It is heart-wrenching to watch in such a small, fragile creature. It's exactly the same pattern as followed by LBB a week ago and it signalled his final fading moments. 

We've done all we have in our power to do and given Lucy another 2 weeks of life that she could never have had when we found her - indeed, she seemed to have lost her fight for life then, when she managed to make a miraculous recovery, spurred on by LBB who at one point even tipped her back on her feet.  

Lucy exploring the tub

Armchair Action

Likewise, Holly created a bit of a scare this morning; she too was a bit still and lifeless and not up to her usual antics. BCW assures me that during the day she sprung back into action albeit with perhaps more rest than usual. That's still true this evening, although what activity I did see seemed usual - just less prolonged. 

What we don't know is whether Holly is affected by the absence of Lucy. I actually think there is some merit to this theory - certainly the introduction of LBB and Lucy increased Holly's activity, who for a while we were quite concerned about. Prior to that introduction, Holly was spending a lot of time just resting under the moss and not exploring, not even inside the nestbox, let alone the main tub. Lucy and LBB seemed to create something for Holly to do; whether it was just tidying the nest after their interruptions, or merely the "social" interaction (the bees do, after all, occasionally shove each other about and walk on top of each other!) we shall never know. So I'm wondering now whether Holly will return to her more reclusive behaviour? 

Of course we mustn't forget that Holly is now a hefty 60 days old, at least. In female bee terms that makes her quite the Centenarian - quite entitled to an armchair once in a while!

Slowing Down?

A couple of days ago we "lost" Lucy (TinylittleBee) under one of the pine cones in our indoor tub. We politely woke her from her "outdoor" slumber and she (perhaps grumpily!) returned to the nestbox. But at least we felt she was in the best place for the night.

It left us wondering why the change in behaviour and whether she was feeling ill or slowing down: After all, when your life expectancy is measured in a few weeks, every day can be like 5 or 10 human years. 

We came down in the morning and once again Lucy was not in the nestbox - clearly she had ventured out during the night/dawn and hidden again. We suspected the pine cones, and there indeed was her small behind poking out, twitching slightly as she breathed. Once again we very gently encouraged her out from the cones and offered her a drink.

Now, you might wonder why we would disturb her and possibly stress her more than necessary and generally we would indeed leave well alone? But there are times when behaviour seems a little bit out of the ordinary and we have to make a judgement on whether to leave her (or any of the bees) alone or check whether she is in trouble - e.g. run out of energy, stuck on her back etc.  Intervention is a last resort, but the whole point of rescuing and saving these otherwise helpless bees was to extend their life and give them some "quality" (if it's possible to measure such a thing in the bee world). Lucy has always been a bit weaker than Holly in general, despite having a full complement of wings and legs; so we tend to be on the lookout for her wellbeing.

We concluded that since Lucy had come out of the nestbox during the night, and gone back under the cones, something might be amiss: we saw both BLB and LBB "go off alone" when they were close to the end. Here's the video of us finding Lucy under the cones in the morning. You can see she accepts a drink willingly straight away, with no sign of warning or retreat. In fact both Holly and Lucy are becoming very receptive and placid to our existence and intervention. 

Lucy finally goes back into the nestbox, albeit rather slowly and we resolve to try and keep an eye on her during the day and check her behaviour.

About an hour later, BCW called me down from the office with great excitement! Holly was out of the nestbox! This really was quite something - over the weeks she's been in this environment she's never really left the nestbox. She did at first to come out and explore the area around the entrance to the nestbox itself, but she never explored the full tub. Basically she just did a bit of door patrol. That soon stopped too - so seeing her come right out into the tub and explore the whole area was both delightful and baffling!

I shot some video of them out in the tub together and turned it into something a little more playful to celebrate the moment!

Over the last few days we've monitored Lucy closely. She has slowed down quite a lot: her "active" day seems to have significantly reduced, starting much later in the morning; and we are finding her asleep/hiding during the day outside the nestbox. That wasn't the case a week ago, when she was exploring non-stop. Today we found her embedded head first under some soft tissue by the side of the nest box. We coaxed her out with some honey water which she drank furiously from the end of a little cardboard stick. (It's actually quite a privilege to feed her directly.) After that she did a quick mini-tour of the tub and then went into the nest, so we killed the lights to encourage her to stay in there overnight. 

So - her pattern of behaviour has changed and although she doesn't seem weaker as she moves around, she seems to rest a lot more. BCW compared this to any human who gets old and needs to rest more, falls asleep in the armchair and so on!

I guess she has a point.