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!!
