With amazing advances in the world of tech and science seemingly coming every day, sometimes realizing what we don't yet know can be staggering.

For example, until very recently, we couldn't be 100 percent certain about what happens within a cocoon (scientific term: chrysalis) when a caterpillar metamorphoses into a butterfly. While dissection gave us a fairly good idea of the process, it wasn't until researchers at the University of Manchester used 3D scanning technology to take a peek at the process that we knew for sure what happened to caterpillars when it was time to change.  Cue appropriate theme music: 

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Tristan Lowe, Robert Bradley and Philip Withers, three researchers affiliated with the university's X-Ray Imaging Facility, teamed up with Environmental Science researcher Russell Garwood and an expert on Life Science from London's Natural History Museum named Thomas Simonsen. They used x-ray computed tomography (CT) scans to document the metamorphosis of a painted lady butterfly.

The team took 2000 x-rays of Vanessa cardui pupas as they made the transition to butterflies. The scans were rendered as 3D images that showed the development of the tracheal airways, the antennae and the midgut (from which parts of the digestive tract develop).

The resulting paper, "Metamorphosis revealed: time-lapse three-dimensional imaging inside a living chrysalis," was published in the July issue of Journal of the Royal Society Interface, which can be viewed in full here.


This image, created using 3D scanning technology, shows the development of the painted lady butterfly's tracheal system (blue), midgut (red) and Malpighian tubules (orange) over the course of 13 days.

The 3D scanning method boasts several benefits over the traditional method of dissection. Where dissection requires killing a specimen at precisely the right developmental stage, CT-scanned chrysalises can be observed in vivo. 3D scans also document intermediate periods between distinct developmental benchmarks better than traditional dissection.


Labeled pupa comparison at day 1 and day 13.

Watch a video of the development below:

The researchers hope that 3D scanning can help in the future by allowing scientists to identify taxa quickly. They also claim that the method of observation would be helpful in studying metamorphosing insects that vary greatly from the traditional model, as well as the development of mutations.

Bringing the paper's findings outside of the world of insects, the researchers conclude that their work could help bring down "flawed arguments such as irreducible complexity" that are often trotted out by the "creationist threat" when faced with "complex systems which are hard to analyze."

Because the caterpillar's vital systems are broken down and replaced without causing the death of the caterpillar, research like this can be cited against arguments like irreducible complexity, they say.