One thing I’ve learned about caterpillars is that their heads look TERRIFYING under a scope. So many appendages and hairs and spines and eyes… the mouthparts of a caterpillar look like something straight out of a horror movie.

I have never been a big fan of fiction, and it’s because there are so many crazy things in real life. I don’t see much need for making things up. Caterpillars reaffirm that belief.

Here is a shot of my first mandible dissection. I used a species of cutworm, my advisor had a bunch of extras and said I could use them as practice. I first cut off the heads, and soaked them in a solution of KOH to dissolve the soft tissue. I then attempted to hack off one of the mandibles and the hyperpharyngeal complex. Next step will be to try a few more before doing the real specimens I need to examine.

While hunting through one of the junk drawers around the lab I dug up some brand new needle point forceps, which made the process much easier.

Here is the mandible by itself.

If you have any experience with mandible dissection and have any tips, please let me know! At this point it seem to be mostly luck that I find a way to rip things apart without ruining everything.

Caterpillars are much more fun when they’re alive. But since they can’t live forever, and they don’t tend to sit still for very long when you’re counting setae or crochet hooks, they must be preserved as specimens.

Unfortunately, they cannot simple be pinned like adult moths. As you can imagine, their bodies would quickly rot and you would have a tray of smelly goo.

The most popular method is to quickly boil them alive until they stiffen, and drop them into a vial of 70% or 95% (if you want to preserve DNA) ethanol. This process is somewhat traumatizing when you have raised a caterpillar from an egg, but there are plenty of ways to rationalize the act of betrayal.

“You will be helping science!”
“Don’t worry, I still love you.”
“I realize you have a nervous system, but it’s debatable whether you feel pain.”
“Oh, I know those thrashing motions and vomit were innate responses. Of course it doesn’t look like you’re screaming, that would be silly.”

Their colors quickly fade once in the ethanol, which is sad considering how vibrant many caterpillars are in life.

Here is a bag of caterpillars I recently loaned to work with:

A close up:

Now, these guys were not terribly exciting when they were alive, but they had many more shades of brown. If you look closely there is a lot of… stuff… floating around the vials along with the caterpillars. Might be gut contents, bits of the caterpillar falling apart… who knows!

And now I must excuse myself to place a few of these into a dish, creating a sort of caterpillar stew, to examine them under the scope.