While we are waiting for the caterpillar robot video links, let's come back to some morphological discussion of lepidoptera larvae. All my biomechanics studies so far are based on a well-known model system tobacco hornworm (Manduca sexta). It is a fair size macro-lepidopera species commonly found in the America. It has 4 pairs of abdominal prolegs plus 1 pair of anal prolegs (or terminal prolegs). This is thought to be the ancestral form.
However, we are perfectly aware of the diversity of lepidoptera species. Caterpillars really vary in numbers and arrangement of prolegs. They also adopt different gait patterns accordingly. So how do we generalize what we learned from Manduca? Or can we?
To find out why, I am planning a field study to compare body overall scaling across different species of caterpillar. Although much work has been done on comparing morphological changes in the evolutionary context of species interaction, little is known about the physical constraints during evolution. I believe that there is a link between locomotor biomechanics and the evolution of prolegs configuration.