Imaginal Cells

This article is a compilation and distillation of information gathered from a wide variety of sources as part of my study of imaginal cells. While it was easy for me to find an abundance of beautiful and inspiring stories about caterpillars transforming into butterflies, it took some significant searching before I was able to discover enough scientific evidence to convince me that imaginal cells were indeed the real deal.

The most creditable information I found came from Stanford University School of Medicine Doctors Molly Weaver and Mark A. Krasnow, at the Howard Hughes Medical Institute and Department of Biochemistry. Their research addresses questions such as, “when tissues are damaged, what kinds of cells replace them, and how are they recruited;” and their report, “Dual Origin of Tissue-Specific Progenitor Cells in Drosophila Tracheal Remodeling,” instilled a new sense of wonder and appreciation in me for Nature’s wisdom.

I have done my best to translate the research into common language that makes sense to those of us who do not have a Ph.D. in biochemistry. Unfortunately, this means I had to exclude some of my favourite terms, such as fate mapping, molecular timer and multipotent state. I love those!

I must admit I am more a poet than a scientist, so please allow some artistic license as you read my very non-scientific explanations that follow.

After a caterpillar buries itself inside its cocoon, it slowly begins to transform into a butterfly or, more commonly, a moth. The caterpillar does not merely shrink and then sprout wings inside there; instead, it first disintegrates into a mass of ooze within the cocoon. If we were to open the cocoon halfway through the process, we would not find a half-caterpillar, half-butterfly creature, but a blob of goop (See, I told you – no technical terms!).

What happens next within this ooze is that a new type of cell begins to appear, similar to the way an image appears in our minds. The pre-existing cells do not change into these new cells; the new cells just seem to come out of nowhere! These are the imaginal cells.

[This next part about life cycle reminds me of critical mass, the hundredth monkey and the dark night of the soul.]

At this amazing stage in the life cycle, the imaginal cells “wake up.” When this activation occurs, the imaginal cells are instinctively drawn to one another. When enough of them connect, they become the genetic directors of the future of the caterpillar. The exact amount of imaginal cells that must connect in order for the caterpillar-to-butterfly transformation to take place is unknown, but it appears to be less than 50%. At that crucial point, the other cells begin to putrefy and become a nutritive soup – feeding the imaginal cells while they create the miracle of the butterfly.

As this process continues to unfold, some imaginal cells start changing into wing cells, some change into antenna cells, some into digestive tract cells and so on. In other words, they are no longer imaginal cells, but become specific butterfly tissue cells. By the time the butterfly emerges from its cocoon, it is impossible to find any imaginal cells remaining in its body.

In the 1940’s, Alcoa used the term “Imagineering” to describe the way it blended imagination and engineering. Walt Disney used it a decade later to describe the skill set embodied by the Disney employees known as Imagineers. Imagineering might also be a good description today of what’s behind the creation of a butterfly.