Cutting the larvae was difficult, because these bipinnarias keep swimming around. In addition to tracking and anticipating their movements, I had to be careful not to break the tip of the glass needle I used to make a cut. I pulled pipettes using a Sutter Micropipette Puller. They are so sharp, their ends so miniscule, that they cannot be seen with the naked eye. I broke 5 needles while cutting 15 individuals!
Finally, towards the end of the procedure, I started to get the hang of trapping the larva and cutting it without poking myself or breaking the needle! After the bisection, the two pieces of the larva swam away as if nothing had happened! I will follow the regeneration of these larvae, taking pictures as they develop. I hope to witness organogenesis, the formation of organs, until the larvae are complete once again!
Vickery, MS and McClintock, JB. 1998. Regeneration in metazoan larvae. Nature. 394: 140