The thermogenesis of a moth under an IR camera

Is a moth warm-blooded or cold-blooded? If you google this, some would tell you it is cold-blooded. They are not completely right. This infrared study shows how a moth warms up before it can fly. So at least a moth is warm-blooded when it moves.

The moth (is this a winter moth -- operophtera brumata?) was kept in a glass jar. The first IR image shows that when it was idle, its body temperature is the same as the ambient temperature. This means that it does not lose energy to the environment -- a clever way for saving energy and probably protecting itself from predators that hunt by detecting thermal radiation.

However, before making a move, it needs to warm up its flying muscles (near its head where the wings are attached, called the thorax) to above 30 degrees Celsius. In this observation, the warming process took 1-2 minutes for the subject, as shown by the sequence of the IR images to the right. (Note: You may only observe this effect when the moth is energetic. A moth on the verge of death does not have enough energy to warm up.)

Click to view a larger image

Note that we used the automatic color remapping, i.e., the heat map is rescaled based on the lowest and highest temperatures detected in the view. As a result, while the moth warmed up and appeared more reddish in the IR view, the background -- in contrast -- became bluer in the IR view. This, however, does not mean that the temperature of the background has decreased. This automatic remapping could create some confusion, but it is necessary in many cases, especially when you don't know what to expect. It maximizes the difference by increasing the contrast and, therefore, allows the observer to pick up subtle changes like this one.

The last image shows that, after the temperature was high enough, the moth started to move. In this particular experiment, the moth responded slowly because it could have been exhausted as it had struggled quite a bit in the jar before it was imaged.

What interests me in this experiment is thermogenesis: the process of heat production in organisms. What biochemical reactions are responsible for the thermogenesis in moths and bees? Can we learn from them to find a green way to heat our homes?

Design your own house with Energy3D

Energy3D is a free, open-source tool we are developing from scratch to empower students to design, make, and test energy-efficient model houses.

Today we had some students design and make their own houses. One student succeeded in designing a model house after her own real house. The first two screenshots show her model under the sun in different months.

Like many architecture design tools, students can "walk" into their own design and imagine "living in the house" virtually. The other two screenshots show two close-ups: one from the outside and the other from the inside. The fifth image is a physical house made of foam board and assembled, based on this design.

If they are satisfied with their designs, students can "print" out their houses, cut out all the pieces, and assemble them.

We feel that computer-aided design tools such as Energy3D would be a big help to students when they are undertaking complicated engineering design challenges such as making a house. 3D reasoning is usually difficult for most students. A What-You-See-Is-What-You-Get (WYSIWYG) CAD tool can help them think through.

You may be wondering why we want to develop this tool. Many students complain that their science and engineering projects in schools are not challenging enough to be interesting. Many teachers do strive to make their student projects more attractive. However, they lack appropriate educational tools to do so. Energy3D is an attempt to provide teachers and students with cutting-edge tools that can teach and learn modern full-cycle engineering processes--from design to manufacturing to test-- through an interesting project about energy-efficient houses. We hope this tool would intrigue, inspire, and prepare students for STEM careers.

PS on 7/28: This is another building designed by the same student, which shows an intersecting roof. These examples show that Energy3D could be used to design quite a variety of architecture. It turns out that roof is the most difficult part to design using tools such as Google's SketchUp. We are trying to simplify that part by figuring out algorithms that would enable easy editing of roofs. Our work focuses on two directions. First, an algorithm is needed to automatically generate a roof of a given type based on the boundary walls the user has laid. Second, the topological transformations between different types of roofs need to be identified so that we can build the user interface for adjusting the roof easily.

An infrared view of bees

A bumble bee.

I have been wanting to see what I can do with IR imaging in my backyard. Folks at the Discovery and Animal Planet channels use IR imaging regularly to show thermal patterns of animals and plants. So I guess I could do something with it. I cannot afford a high-definition IR camera. But I think my low-grade IR camera should be able to catch something. Here is an interesting story about bees.

Bees are warm-blooded insects. In order to fly, bees must heat up their flight muscles to above 30^oC. So let's check this using an IR camera.

Indeed, a bee looks warm through the IR camera. To be more specific, the thorax of a bee appears to be warmer than the rest of its body (see the IR image to the right). I observed both a honey bee and a bumble bee. Both types have a warmer thorax, where the flight muscles are located. Exactly why the muscles can operate only at a warm temperature is an interesting question.

Bees are known to form societies that depend on successful division of work. Researchers have been using high-definition IR imaging to study bee behavior. With the assistance of IR imaging, German researchers led by Prof. Dr. Jürgen Tautz at Würzburg University found a new type of role known as the heater bees. The heater bees are responsible for maintaining the temperature in the hive where young bees (pupae) grow in sealed wax cells. The bees purposely leave some empty cells among those pupa cells so that the heater bees can crawl into them to warm up the pupae. By varying the temperature of each pupa they can determine what kind of bee it will become. As a result, the heater bees are vital in determining what job a young bee will perform once it matures. In the IR video, heater bees' thoraxes also appeared to be warmer, agreeing with what I observed using my IR camera for a worker bee.

Another article published in Optics Express discussed using IR imaging to evaluate beehive population. The idea is based on the assumption that the more bees in a hive, the warmer it would be. An unhealthy colony that has lost population would appear colder in the IR view, as the number of heater bees might have died down because of the lack of worker bees and hence the food they bring back. And if there are not enough heater bees, the pupae would not grow up normally, worsening the situation.

If you don't want to disturb bees and get stung by them, the non-touch, non-invasive IR imaging is probably the best way to go. :-)

PS on 8/3/2011:

Other flying insects like flies, dragonflies, cicadas, and wasps have a similar thermogram (i.e., warm thorax while active). See these two additional images. Or see this blog post about a moth.

I didn't observe warming in ants. They probably don't produce heat. Or they could be just too small to emit any appreciable IR radiation.

Use a garden nozzle to create a rainbow

You don't have to wait until it rains to catch a sight of rainbow. You can create one any time as long as there is sunshine. Just use a garden nozzle to create a mist and you will see a rainbow.