ScienceDaily (July 22, 2010) — Biologists at Tufts University's School of Arts and Sciences studying crawling caterpillars have reported a unique "two-body" system of locomotion that has not previously been reported in any animal.
Caterpillars have a unique "two-body" system of locomotion that has not previously been reported in any animal: the gut of the crawling caterpillar moves forward independently and in advance of the surrounding body wall and legs, not with them. (Credit: Image courtesy of Tufts University)
In an article published online July 22 in the journal Current Biology, the Tufts-led team reported that the gut of the crawling tobacco hawkmoth caterpillar (Manduca sexta) moves forward independently of and in advance of the surrounding body wall and legs, rather than moving along with them. Collaborating with Tufts were researchers from Virginia Tech and Argonne National Laboratory.
"Understanding this novel motion system may help efforts to design soft-bodied robots," said the article's senior author, Barry Trimmer, Tufts professor of biology and Henry Bromfield Pearson Professor of Natural Sciences in the School of Arts and Sciences. "It may also prompt re-examination of the potential role soft tissues play in biomechanical performance of humans and other animals."
Surprises Inside the Caterpillar
Anyone who has ever observed caterpillars knows that they crawl from back to front in waves. But advanced imaging reveals a surprising picture of what goes on inside.
The researchers used synchronized X-ray and visible light microscopy and videos to study the relative timing of movements of the crawling caterpillars' gut body wall and prolegs (unjointed leg-like structures on the mid-body that grip).
They found that the gut -- essentially a tube suspended at the rear and head of the caterpillar and decoupled from the body wall -- moved nearly a full step in advance of the surrounding structures. In contrast, gut movement was "in step" with motion of the head and rear.
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+++++Current Biology, 22 July 2010 | Copyright © 2010 Elsevier Ltd All rights reserved. | 10.1016/j.cub.2010.06.059
Visceral-Locomotory Pistoning in Crawling Caterpillars
Michael A. Simon,William A. Woods,Yevgeniy V. Serebrenik,Sharotka M. Simon,Linnea I. van Griethuijsen,John J. Socha,Wah-Keat Lee,Barry A. Trimmer
Highlights
The gut in crawling Manduca sexta caterpillars moves independently of the body wall
This visceral-locomotory pistoning offers evidence for a nonlinear elastic gut
This two-bodied biomechanical system is a novel finding in animal locomotion
Summary
Animals with an open coelom do not fully constrain internal tissues [1,2,3], and changes in tissue or organ position during body movements cannot be readily discerned from outside of the body. This complicates modeling of soft-bodied locomotion, because it obscures potentially important changes in the center of mass as a result of internal tissue movements [4, 5,4, 5]. We used phase-contrast synchrotron X-ray imaging [6,7,8,9,10] and transmission light microscopy to directly visualize internal soft-tissue movements in freely crawling caterpillars. Here we report a novel visceral-locomotory piston in crawling Manduca sexta larvae, in which the gut slides forward in advance of surrounding tissues. The initiation of gut sliding is synchronous with the start of the terminal prolegs’ swing phase, suggesting that the animal's center of mass advances forward during the midabdominal prolegs’ stance phase and is therefore decoupled from visible translations of the body. Based on synchrotron X-ray data and transmission light microscopy results, we present evidence for a two-body mechanical system with a nonlinear elastic gut that changes size and translates between the anterior and posterior of the animal. The proposed two-body system—the container and the contained—is unlike any form of legged locomotion previously reported and represents a new feature in our emerging understanding of crawling.
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PERGUNTA INDISCRETA DESTE BLOGGER:
Este sistema de locomoção da Manduca sexta não está com cara de complexidade irredutível??? Eu acho que está, gente!!! Se for, vai ser um Darwin que nos acuda na Nomenklatura científica. A Galera dos meninos e meninas de Darwin vão chorar as pitangas. Por que a natureza se mostra tão pródiga em revelar seus mistérios de complexidade irredutível em seres tão insignificantes??? O primeiro foi o flagelo bacteriano, agora será que o sistema de locomoção biomecânica de uma mera lagarta?
Cruz, credo, Darwin, os bichinhos estão detonando a maior ideia que toda a humanidade já teve...
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PERGUNTA INDISCRETA DESTE BLOGGER:
Este sistema de locomoção da Manduca sexta não está com cara de complexidade irredutível??? Eu acho que está, gente!!! Se for, vai ser um Darwin que nos acuda na Nomenklatura científica. A Galera dos meninos e meninas de Darwin vão chorar as pitangas. Por que a natureza se mostra tão pródiga em revelar seus mistérios de complexidade irredutível em seres tão insignificantes??? O primeiro foi o flagelo bacteriano, agora será que o sistema de locomoção biomecânica de uma mera lagarta?
Cruz, credo, Darwin, os bichinhos estão detonando a maior ideia que toda a humanidade já teve...
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