Our nest continues to grow and with it the activty, interest and intrigue. At the time of writing I've only managed to count in detail 2 days' worth of CCTV footage, but it's one heck of a two days!
Over the course of the two days - half of which was rainy/windy we saw:
- 304 foraging trips
- 136 memorisation procedures (equates to first flight of new bees - indicative on the minimum number of workers in the nest)
- Orangey/red and pale yellow pollen being collected
- 5 Queen bees performing memorisation (i.e. 5 new queens)
- 2 Queens bringing back pollen (normally a sign of colony building - another colony already developing?)
Here's a recap of today's additional activity.
First of all, Queens. When there's unusal activity going on in the nest, it's easy to start doubting what you are seeing. What seems to happen is I start off with an instinct that something is happening because of a short observation. Then I spend a day or two thinking I'm going mad. Then, I typically see really good evidence that shows it was happening. The I start to think I am still seeing things!
It's like that with the queens. I thought I saw one, but I assumed she was the colony "mother". Then of course I saw two so knew something else was going on. And finally at the latest count, five.
I can count them, by the way, by combining a number of techniques. First is sequential exits/entrances. If 3 leave without returning, then I know there are at least 3. Likewise, sometimes I will have counted some that have left, and then see more in the nest at the same time, so this also gives a number. Finally, I can count the memorisations - which is done once (usually) for each new bumblebee that goes on a flight. Using all this data serves to give a guaranteed minimum number with a high degree of confidence.
Anyway, some pics of the queens. Compare the sizes with the regular workers.
And then the queen goes into the nest - and you can clearly see all her pollen (shows up white under the infra red)
Another queen emerged, but had imperfect wings and was struggling to make her first flight. It took her about 20 minutes of trying to lift off, but she could not sustain flight very well. unfortunately I lost track of her..
Since I've been doing some audio recording of the nest this year I also took the chance to measure the audio frequency of these Queens' buzz. The result was 135Hz +/5Hz. This ties in perfectly with the samples I took from captured queens. It stands to reason that frequency and size are related (in general at least), as is true for the human throat/chest and any musical instrument. It certainly would be nice to have a clear frequency range for queens that guarantee you know what you are dealing with. (I'm not finding a lot of research on bumblebee frequencies).
I caught one busy bee "fanning" today. This is the process of beating the wings to draw cooler air into the nest when it is too hot. To be honest, the temperature wasn't that hot. Outdoors it was 16C, and ambient in the nest was 23C (it's been hotter - thought bear in mind this is not the core). Perhaps this particular bee has a low threshold for fanning.
Actually, this was a theory I postulated last year - that different bumblebees have different trigger thresholds. Firstly, from a natural variation point of view it almost stands to reason. But secondly, in terms of a distributed "control system" for the nest that ensures fanning is not "all or nothing" but happens in a controlled way in response to increasing temperature, it makes sense that some bees are more sensitive and start fanning at a lower temperature. As the nest temperature climbs, more bees will be triggered to join the throng. Providing the fanning process itself doesn't generate undue heat, then such a system would basically be wonderfully self regulating (without the need for central command and control), because as more bumblebees start fanning, not only will the effect be greater, but fewer will be working in the nest and generating core heat.
The she moves right to the entrance and continues. She was here for a good few hours (seemingly unnecessarily).
I couldn't capture the sound of her fanning, but at peak temperature it sounded as though others in the nest were also doing so, so I recorded some of that and measured the frequency also. Because the sound is coming from the wings more than the thorax, it is not the usual buzz but the whisper of the wings through the air at a slower speed than normal flight (like a room fan). It's hard to determine if there is a fundamental frequency, but for what it's worth, my meter showed 135Hz sustained for extended periods of time. Interesting in that it is the same fundamental as the queens' buzz, but it is not a buzz and does not have the same characteristics.
It was pretty much certain we'd get some less well bumbles to care for indoors again this year - there are always imperfections in nature. I'd hoped it wouldn't be too soon, but it was today. Actually, this box has gone longer than last years before discovering some under-formed bees.
I actually found two - and they insisted on coming out of the nest and trying to fly but were unable to. The first one is worst off, with only 1 wing and 5 legs and I found her about 6 feet from the nest. Lucky for her really, as if I hadn't spotted her then I might never have done and she could be starved or bird-food by now. The second one has both wings, but they are crooked, one is too small, and she can't fly. (I made sure for 30 mins in the open that they couldn't, but it's obvious anyway).
They are both similar size, and very small, under 1cm. I've not managed an accurate measurement yet, but around 8mm I reckon. Possibly smaller than Holly. I'm actually pleased to have found two as they can offer each other company and interact with each other. Last year one of the most painful things was to see Holly behaving as if she was depressed when she was alone (she had company from other bees some of the time, but she outlived them all). You think I'm kidding?
Here are our two little darlings, just resting nest to each other. Maybe they are bonding ☺ They are certainly getting on fine:
Although it is not recommended to revive bumblebees by feeding on honey water, we have no option. Sugar water does not provide mineral content, it is just empty energy and not nutrition, so we have to provide honey, even though there is a risk of bacteria. Last year Holly actually survived 70 days in our care, which is as astonishing life span for a worker bee (typically 15 - 20 days).
Tonight they have drunk really well and been mooching around with plenty energy, don't seem to be stressed and are co-operating just fine. They won't grow any bigger - their exo-skeleton has developed to this size and that's how it will stay, so they are amongst the smallest in the colony. Perhaps they hatched too soon, or just didn't get the temperature needed for development (which is critical). At least they are mobile.
I hope these two have a decent lifespan, but whatever the case, we will give them a good quality of life however long it is - free from predators and starvation.