Reconsidering "caterpillar locomotion"

Want to guess the highest speed by which a caterpillar can move?
Answer: ~15" per second!!!
No way... what species and how?

I recently reviewed a few papers about rolling locomotion in nature, and Mother-of-Pearl moth caterpillar (Pleurotya ruralis) is one of the two active rollers ever discovered. Check out a YouTube clip by BBC Aniamls and you will believe what I claimed. In this movie, the caterpillar was rolling downhill, but the rolling action is actually initiated by rapid muscle contraction. According to Dr. John Brackenbury reported in his paper "Fast locomotion in caterpillars", this active rolling could hit a top speed of 39cm/s.



Here are a couple of references for those who want to read into this subject.
J. Brackenbury. Fast locomotion in caterpillars. Journal of Insect Physiology. 45:525-533 (1999)
J. Brackenbury. Caterpillar Kinematics. Nature. 390:453 (1997)