Hot under the Thorax

Today I started the process of systematically reviewing our CCTV footage to note down the "first exit" and "last arrival" times of our bumblebees. This is something I am curious to plot - I don't expect to find anything particularly astounding but I'm interested to plot the graph and see if it follows a pattern, such as sunlight times. Or whether there is some other pattern that can be identified. I ended up not getting the job finished, partly because I also started review the footage from when we first installed the DVR and also the camera into the hive. Actually, it was kinda funny - when viewing the footage from when we put the camera into the nestbox, it's like something from Blair Witch project! It's dark and jerky, lots of shots of the ground, flashes of faces, every once in a while you see the stanley knife I used to cut the box, and then you see flashes of my infra-red face while wearing marigolds! 

Early Bumble

It was very windy today, so while out in the garden I saw an Early Bumblebee on the Lavender hanging on for dear life! It was clinging with all its might, legs wrapped fully round the flower trying to stay hanging on. This gave me a chance to try some macro photos of it, although the wind was a nightmare and most of the pictures were pretty blurred. Of course, I could have upped the ISO setting on the camera to use a faster shutter speed, but that creates more noise which is undesirable; and actually didn't solve the biggest problem which was trying to track the focus. Anyway, I still got some reasonable pics:

 Early Bumble Bee - Bombus Pratorum - Male (see the moustache!)Early bumble bee - bombus pratorum

It turns out we are seeing male Early bumbles. We can tell they are males because:

• they are not collecting pollen (they don't, they just feed for themselves)
• they have a moustache
• they have 13 segments on their antenna, not 12 like the females

 At one point one of these males flew onto BCW's bright purple jumper, so I got a great photo of it there:

 Early Bumblebee (Male - Bombus Pratorum)

It's a amazing how bright and fluffy they are! They are very unmistakable!

Cold Bufftail

Shortly after we spotting a Bufftail landing on the grass - we weren't sure if it was one of ours or not, but we suspected at first it was just struggling to fly in the gusty wind and was bedding down in the grass for a few moments. Again, I took the opportunity to get some close up photos, although this little bee was more inclined to give me her warning leg.

Bufftail Bumblebee (Bombus terrestris) resting and warming in the grass - also with some grey (Broad Bean) pollen in her basketswarning leg from BufftailEventually we figured that perhaps she was too cold to fly and could do with some help to warm up as we didn't know if she was one of ours (in which case we could have just transported her to our nest box). So I got the garden patio heater out and started to heat the area where she had landed. Within about a minute she buzzed and did some short flights of a few inches, so we knew she was warming up. The ground around her by this time was climbing, and ranging between about 30 degrees and 50 degrees. Within another 30 seconds she was all warmed up and off! She flew over the fence, so we don't know whether she was one of ours or not - either way, it was great to get her on her way!

Now here comes the science bit

A quiet day on the bee front today. BB6 didn't come back as I suspected. Although it was a beautiful day to start off with, by the afternoon it had clouded over, so I'm not sure there was going to be much activity anyway.

However, the was some activity from the postman - he delivered the new tech from Maplin! Always good to get new tech. Today's delivery consisted of the gear to make an infra-red spotlight (hello mr. soldering iron!) and a laser-guided infra-red thermometer. More on that in a moment. 

Infra-red floodlight kitThe idea with the floodlight kit is to light the area around the nest and allow some light to leak inside the box to help with the vision on the camera in the box, which is sensitive to infra-red. I guess if I'd been better prepared I'd have infra-red emitters mounted inside the box itself, but this is a starting point; besides we need to see if the bees object. 

If you search on the internet you can find information about what wavelengths of light bees can see; some of it is a bit mathematical. The bottom line is, basically, they don't see infra-red. Their vision is very much skewed to the Ultraviolet end of the colour spectrum and they possibly see up to 600nm (nanometres) wavelength of light. This is an orangey-red colour. 

The light I will be using is 850nm - well above the limit of their range (and indeed, humans).

There is the question of whether they will sense heat from the infra-red. I need to do more detailed research on different wavelengths, but what I discovered was that infra-red from the sun accounts for about 500w of heating per square metre of the earth. (This is about half of the 1kw of total heating that other wavelengths account for).  This floodlight will be filling an area much larger than that (perhaps 5 times) with perhaps 1W or 2W of light. Overall this is about half a percent of the Sun's energy so I feel this is safe and unlikely to affect any bees. Of course, I shall monitor it closely to confirm whether this is the case. 

It could well be that the additional heat is beneficial to them, at least on colder days; makes me wonder whether an infra-red floor in the box would be nice and toasty for them! 

Measuring the temperature

The second piece of tasty kit is the temperature sensor. Oh how I love it!

Infra-red temperature sensorThis clever device basically lets you point at an object in the distance and measure its temperature when you pull the trigger. It's amazing! It has a very rapid response time and also remembers the max temperature at the time; so you can actually sweep the room with it and easily find the max temperature. It's laser guided too, so you can accurately point it at your target. The closer you are, the smaller the area it measures of course. 

I've been testing it out and it's amazing how different surfaces and materials store and radiate heat. This afternoon, anything metal was cool, whereas the paving stones on the path were actually warmer than the ambient temperature (having stored heat while the sun was out). It seems possible to measure ambient temperature from the air although really it is designed to measure surfaces. 

I tested it against the thermometer in my room, pointing it at the surface of the thermometer and it tallied within 0.1 degrees, so I am happy and confident it is fit for purpose. 

So, what is that purpose? Well, basically I want to be able to measure and track the temperature of the nest boxes. Obvsiouly on the outside, but by pointing through the entrance hole, also potentially on the inside. This will serve a few purposes. 

• If we ever get a bee colony it will confirm the temperature they operate at (30 degrees) which will satsify my curiousity!
• Before we obvisouly get bees, we may be able to tell whether we have a queen in residence if we can detect any temperature shift. 
• I can start to correlate outdoor temperatures with the activity of the bees in general. 

All of this will add to my own body of research, even if it's all well understood by the scientific community already. As a starter I took some readings today. At the time it was 22 degrees ambient temperature, but the box was at about 17 in the shade. The path was 24 degrees and where the sun was shining on the window, it was over 30!

In fact, I was quite amazed by how variable the temperature was all around me - it just goes to show you can find heat (or cool) if you need to by moving around and finding a new place to rest (if you are a bee). I suppose this is obvious when you think about it, but it really brings it home when you actually measure. Sadly I couldn't afford a thermal imaging camera which would show this, as they start at about £3000!

Notwithstanding, this is a brilliant bit of kit!