It's been very quiet in the nest outdoors for the last two days. "Quiet" meaning no activity at all, save for a small moth that seems to have been in there a few weeks - and doesn't seem to have done any harm.
It's cold now, down to 3 degrees or so overnight at times and only peaking at about 12 degrees during the day, so we don't expect any activity and we certainly don't hold out any hope for any larvae in their wax pots that had been developing. In fact today I took the decision to remove the small infrared lamps from underneath the lodge. Chances are they were have no useful effect anyway, not to mention they are only partly functional.
Notwithstanding, we've left the nest intact for now, just in case. We've been surprised so many times this year, that we will just wait a week or so and be sure there is no life left in the lodge. Then we'll have the (fairly) gruesome job of cleaning it out and examining just how much work our 4 queens and their workers have done. We've contemplated sealing the lodge and placing it in the garage - still monitored by CCTV - just as the final stage.
However, indoors we have a happier tale. Our tiny rescued indoor bumble, the last survivor of the nest was rescued two days ago and has survived indoors for two full nights and is now entering her third. At times she's caused us a little concern with her stillness, but in general she's been agile and we've seen her take a very good drink today, so she's getting nourishment.
Of course her rhythms will be all over the place as she has no siblings to work with; has 5 or 6 fewer hours of daylight than would be the case in summer; is not in a fully sealed/dark location and, indeed, is subject to the artificial lighting in our home. Although we do try and maintain a fixed routine of light to help her rhythms. Having said that, it is already established that bumblebee Circadian Rhythms are rather elastic: while forgaging has to take place during daylight, we've observed much activity that takes place over night. (Take our little bee that spent 7 hours through the night fixing up the nest bedding we added!). There's lots that happens through the night, so we shouldn't be surprised if our little guest rests during the day from time to time.
We've been helping to heat her tub a little by placing it near or on a microwaveable wheat bag, just to improve the ambient temperature. We noticed today she was particulalry responding to this - when the bag is intially hot she moves away from it to another part of the tub. When it is at a nicely warm temperature she comes and tucks up towards it as close as she can get (through the plastic box of course). You can see an example of this in the picture below.
We noticed at one point we probably made the wheat bag too warm and she very quickly scooted off to the other side of the box! It confirms the bumbles are sensitive to temperature and definitely have a favourite comfort zone.
In case you are wondering, for this very reason we don't heat the whole box, just a region of it. This means she has the freedom to find the perfect spot in the temperature gradient. We've also added materials she can climb on and get right away from the floor of the tub, such as a "bridge" made from a cardboard toilet roll inner-tube. We saw her climb it today which was entertaining to see! And tonight she is tucked up sleeping underneath it - perhaps she feels secure with something over her head.
We've also noticed that she tracks the temperature gradient as the box cools down. To start with she is typically tucked up close to the edge of the wheat bag, where the rest of the tub is cool. Gradually she moves as the wheat bag cools, until, as in the picture above, she is tucked up to the now-warmest part at the front of the box. Just like Holly she seems to like the warmth.
Finding her wings
Mid morning we noticed she was stretching flapping her wings. While it's good to see her wings are well-formed, it creates a dilemma for us, because we've only ever kept bees indoors that couldn't fly. If she could fly we would feel like she was being unfairly caged - and yet she would have no chance of survival outdoors; there are no flowers in the vicinity for nectar, and one cold night could see her off. And she is so, so small, that her energy stores are small - meaning she needs to top up regularly (a bit like the way a baby has to feed regularly).
We discussed the concept of being able to exercise her natural instincts (i.e. freedom to fly outdoors) versus a warm and secure environment meaning less stress on her body. While she might have instincts to leave the nest and forage, this is not an experience she has ever known and the stress to her system would be huge. We concluded that it is reasonable and right to keep her safe indoors.
As we watched her behaviour, wondering if she was indeed trying to take off, I realised her activity patterns matched something I have seen before: it looked like she was "fanning". This is what bumblebees do to try and regulate their nest temperature, especially when it is getting too hot - and it's something we managed to catch on video.
We noticed that she was moving around the box to the various temperature zones she'd already picked out and then buzzing her wings for a few minutes. On occasions it looked like she was moving to one spot, fanning to move the warm air around, then moving to a cooler spot for a few seconds to check the temperature, then coming back to where she had been and starting again. It certainly looked like she was trying to even out the temperature in the tub. What we can't be sure is if she was trying to make the warm zone cooler, or the cool zone warmer - but she was fanning in the warm zone.
Other factors made it look like she wasn't really trying to take off: she was often up against the tub (so much so her wings were catching it) and facing the wrong way; and the tell-tale sound was that of her wings "fizzing" in the air, rather than her thorax buzzing, which is what gives bumeblebees their disctinctive "throaty" buzz when they fly. There's a certain stance too and a certain way of spreading their wings which, I presume, increase surface area.
It's very quiet, but I was able to record the sound of her fanning on my iPhone - you can play it below:
If we are right, then there are two things I find amazing about this:
- Nothing has taught her this - this is inbuilt, instinctive behaviour to use her wings to control the temperature of her environment. She's not had any time with live siblings and not seen this behaviour. It's totally in her genes.
- It means she has accepted the tub as her nest - so, even though it is missing many features, such as a Queen, other siblings, wax pots, the right smells, the right lighting, and even an exit(!), she must have accepted this is "home". This means, that although we can't let her outdoors, she can play out her nest instincts and do some of what nature intended. That makes it a little easier to accept we have her in a closed environment indoors.
We just take each day as it comes now - every one is a bonus, for her and for us. As the remaining survivor of her family line we hope she can hang around for a little while yet.