Washington: "Weird movements" in the guts of freely crawling caterpillars could improve the design and development of soft material robots, according to researchers at Virginia Tech.
The interdisciplinary research team, led by Michael Simon of Tufts University`s Department of Biology and Jake Socha, used a type of powerful X-ray imaging to discover internal soft-tissue movements that were massively out of sync with the external body movements.
They then verified these findings using transmission-light microscopy to see the internal soft-tissue movements of smaller, translucent caterpillars as they slowly inched their way along a glass microscope slide.
As the dissection microscope magnified the images, the researchers recorded them to a video camera, and then captured them on a computer.
This combined imaging showed that the caterpillar`s gut slid forward in advance of the surrounding tissues.
It is "unlike any form of legged locomotion previously reported and represents a new feature in our emerging understanding of crawling," said the researchers.
The novelty is that the caterpillar`s center of mass moves forward while the middle ``legs`` are anchored to the substrate.
The internal gut movements are locally decoupled from visible translations of the body.
"This type of two-body mechanical system has never been seen before, and is probably unique to soft, squishy animals," explained Socha.
This movement meant the abdomen typically advanced an entire step forward before the body wall caught up.
The researchers described it as "a unique phenomenon of gut sliding."
Since the research team is also interested in engineering applications, they moved from considering the biological implications of an internally pistoning gut to potential uses in soft-bodied robots.
Their findings are already finding their way into designing maneuverable and orientation-independent soft material robots.