Gluing Crayfish for Science
A This to That user wrote:
We're currently racing to be the first lab in the world to do fMRI studies with crayfish. (Admittedly, we may be the only ones running this race.) Crayfish, as you probably don't know, are a great, easy-to-use model animal for asking and answering questions relevant to the basic functioning of all vertebrate nervous systems, so by answering my question you will be indirectly benefiting all humankind.Our answer:
What we need to do is glue the carapace of live adult crayfish to the inside of a plastic Nalgene centrifuge tube, which will then be placed inside a tiny (3.7cm) custom-made fMRI coil. We have to glue them in because if the animal moves at all, the image will be blurred. We might also be gluing the animals' eyestalks in place because if they move, the brain moves.
Here's the catch: because adult crayfish of the biggest size are difficult to grow, expensive to obtain, and rather endearing once you get to know them, we'd like to be able to dissolve the glue once we're done so that the crayfish can be re-used, go on living their little crayfish lives, etc. So we need a glue that dries fast, won't dissolve in water, is relatively nontoxic, and can be dissolved by a relatively nontoxic solvent. Any ideas?
Georgia State University
Wow, we have to comment on the uniqueness of your glue request. Just when we thought we had heard it all, there is a questions like this. Who ever heard of gluing crayfish? Anyway your request is a tall order because any glue that is resistant to water will contain a solvent. The least toxic of all the solvents would be alcohol based, so you need to find a glue that contains only alcohol as its solvent. But even then, we wonder what alcohol will do to the crayfish's eyestalks, (actually we just wanted to use the word eyestalk!) All kidding aside, we will put a call out for possible glues that might work for you, but we also wonder if this is a situation that may call for a mechanical restraint rather than a chemical restraint. Check out Jeff de Boer. He is a metal artist who makes armour for mice. Maybe he could design a contraption that could keep your crayfish still, eyestalks and all. Good luck and please keep us posted with your solutions. Thanks.
Update: A kind and smart thistothat reader tells us about ommatophores! This doesn't help us at all with the gluing but we are better for knowing about it. Thanks.
The Surprisingly Awesome podcast looked into this.