The things we don’t know about the natural world could fill textbooks. That’s why excitement is the most appropriate response when we discover new ways to study life and its complexities. Magnetic resonance images (MRIs), X-rays and computed tomography (CT) scans already have well-known uses which regularly change lives, but recent developments will see them be put to use in new ways — in both the human and insect kingdoms.
Insects have traditionally posed a number of difficult challenges for scientists and researchers, but the march of technology has given us a way to see them in a whole new light.
Why Did We Need a New Method?
Human beings may take for granted that we can sit relatively still and quiet when treatment requires us to submit to an X-ray, MRI or CT scan. Insects, on the other hand, are both tiny and fidgety. The radiation required to capture their likenesses in CT scans is harmful to them, and they simply can’t sit still long enough to produce a clear image.
As a result, performing this type of study on live insects has, heretofore, been virtually impossible — the harsh mistress of scientific achievement has always led to the untimely death of the specimen. However, a new method offers a novel approach. Think about what it could mean to capture an image of a living being this small, rather than using and then discarding a dead specimen, which is no longer in a state of active biological development.
Doesn’t that Sound Exciting?
It might sound callous, but researchers can now successfully and temporarily immobilize live insects by applying carbon dioxide to simulate the effect of hypoxia — a lack of oxygen — on the body. For up to seven hours, scientists can now use this technique to perform scans on live subjects. The subject experiences no lingering ill effects from this seemingly rough treatment.
Once the subjects have been prepared, the imaging process can continue apace.
An Insect’s-Eye View
Mini-computed tomography (mini-CT) scans have always required a delicate balance, radiation-wise. The more radiation that gets applied during imaging, the clearer and more useful the resulting image will be. Unfortunately, the radiation used in CT scans is inherently harmful to living cells, meaning scientists have always had to study the resilience of a subject before applying radiation for imaging purposes.
Performing micro-CT scans on insects was no different for Dr. Danny Poinapen and Ph.D. candidate Joanna Konopka, whose study recently appeared in BMC Zoology. They had to devise an optimal scanning process to minimize the radiation dose and image noise without causing irreparable harm to the subject. After working at it, they reached a dosage level 80 times lower than what is typically used for sterilization procedures. The insects can go about their business relatively quickly after these scans are complete, meaning they suffer no impairment of their normal body functions.
After joining this sedation technique with mini-CT technology, the results have been fascinating.
It was already known that micro-CT scanning produces images up to 100 times more detailed than previous-generation methods, but this level of detail meant nothing when test subjects were impossible to image clearly.
Using 3D CT scanning equipment, scientists have even used the methods described above to successfully test for previously unknown and undocumented life stages in insects — something we couldn’t have done with previous-generation imaging technology. Thanks to powerful images captured at resolutions as high as 20 micrometers, we’re literally seeing life unfold in brand-new ways.
If the idea of observing the natural world in a new way doesn’t get you excited, here are some additional reasons why this new imaging technique is a reason to celebrate.
Because this type of imaging is compatible with existing standards, and because it’s so readily applicable to the study of how life changes over time, its creators anticipate it being put to use in parasitology quite soon — a study which touches on both human medicine and the study of the insect world, or entomology. And because it requires no significant retrofit to existing technology, scientists everywhere can start putting it to use right away.
It’s a great achievement — and one we hope to talk about again soon as its implications begin to unfold.