The diversity of hydrostatic skeletons

Kier, William M.

doi:10.1242/jeb.056549

Cited by 202 publications

(173 citation statements)

References 103 publications

Supporting

Mentioning

158

Contrasting

Unclassified

Order By: Relevance

“…Biology can provide crucial insights for designing such systems, as complex biological control problems are often simplified or solved by body mechanics rather than requiring precisely orchestrated neural control [4,5].…”

Section: Introductionmentioning

confidence: 99%

A Model of Larval Biomechanics Reveals Exploitable Passive Properties for Efficient Locomotion

Ross

Lagogiannis

Webb

2015

Lecture Notes in Computer Science

View full text Add to dashboard Cite

Abstract. To better understand the role of natural dynamics in motor control, we have constructed a mathematical model of crawling mechanics in larval Drosophila. The model accounts for key anatomical features such as a segmentally patterned, viscoelastic outer body wall (cuticle); a non-segmented inner cavity (haemocoel) filled with incompressible fluid that enables visceral pistoning; and claw-like protrusions (denticle bands) giving rise to asymmetric friction. Under conditions of light damping and low forward kinetic friction, and with a single cuticle segment initially compressed, the passive dynamics of this model produce wave-like motion resembling that of real larvae. The presence of a volume-conserving hydrostatic skeleton allows a wave reaching the anterior of the body to initiate a new wave at the posterior, thus recycling energy. Forcing our model with a sinusoidal input reveals conditions under which power transfer from control to body may be maximised. A minimal control scheme using segmentally localised positive feedback is able to exploit these conditions in order to maintain wave-like motion indefinitely. These principles could form the basis of a design for a novel, soft-bodied, crawling robot.

show abstract

Section: Introductionmentioning

confidence: 99%

A Model of Larval Biomechanics Reveals Exploitable Passive Properties for Efficient Locomotion

Ross

Lagogiannis

Webb

2015

Lecture Notes in Computer Science

View full text Add to dashboard Cite

show abstract

“…As soft bodied animals, planarians exhibit these body shape changes through the action of perpendicularly oriented, antagonistic muscle groups on weakly compressible internal fluids and tissues, which make up what is called a hydrostatic skeleton (see reviews in (14,15)). Waist formation is key to successful rupture, because it enhances the longitudinal stresses at a given longitudinal tension force exerted by the planarian's musculature by an order of magnitude.…”

mentioning

confidence: 99%

Mechanics dictate where and how freshwater planarians fission

Malinowski

Cochet‐Escartin

Kaj

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Asexual freshwater planarians reproduce by tearing themselves into two pieces by a process called binary fission. The resulting head and tail pieces regenerate within about a week forming two new worms. Understanding this process of ripping oneself into two parts poses a challenging biomechanical problem. Since planarians stop "doing it" at the slightest disturbance, this remained a centuries-old puzzle. We focus on Dugesia japonica fission and show that it proceeds in three stages: a local constriction ("waist formation"), pulsationwhich increases waist longitudinal stresses -and transverse rupture. We developed a linear mechanical model with a planarian represented by a thin shell. The model fully captures the pulsation dynamics leading to rupture and reproduces empirical time scales and stresses. It asserts that fission execution is a mechanical process. Furthermore, we show that the location of waist formation, and thus fission, is determined by physical constraints. Together, our results demonstrate that where and how a planarian rips itself apart during asexual reproduction can be fully explained through biomechanics.Keywords: planarians, biomechanics, fission, rupture, traction forces Significance Statement: How planarians reproduce by ripping themselves into a head and a tail piece, which subsequently regenerate into two new worms, is a centuries-old biomechanics problem. Michael Faraday contemplated how this feat can be achieved in the 1800s, but it remained unanswered because it is experimentally difficult to observe planarians "doing it". We recorded Dugesia japonica planarians in the act and developed a physical model which captures pivotal steps of their reproduction dynamics. The model reproduces experimental time scales and rupture stresses without fit parameters. The key to rupture is a local reduction of the animal's cross-sectional area, which greatly amplifies the stresses exerted by the planarian's musculature and enables rupture at substrate stresses in the Pa range. \body Already Michael Faraday and his contemporaries were intrigued by the observation that asexual freshwater planarians, squishy worms a few mm in length, reproduced by tearing themselves into a head and tail offspring, in a process called binary fission (1). How was it possible for these animals to generate the forces necessary to rip themselves using only their

show abstract

“…Extension of these orientating techniques to three dimensions would enable the creation of combined radial, longitudinal and helical fibres and structures; all key elements underlying the varied achievements of natural muscle, as exemplified by the hydrostatic skeleton [191]. Creating bending and gradated response Considering the system from a different perspective, one can abstract the concept of simply joining materials with differing responses to the same stimulus.…”

Section: Reproducing Positioning and Orientationmentioning

confidence: 99%

Morphing in nature and beyond: a review of natural and synthetic shape-changing materials and mechanisms

2016

View full text Add to dashboard Cite

Shape-changing materials open an entirely new solution space for a wide range of disciplines: from architecture that responds to the environment and medical devices that unpack inside the body, to passive sensors and novel robotic actuators. While synthetic shape-changing materials are still in their infancy, studies of biological morphing materials have revealed key paradigms and features which underlie efficient natural shape-change. Here, we review some of these insights and how they have been, or may be, translated to artificial solutions. We focus on soft matter due to its prevalence in nature, compatibility with users and potential for novel design. Initially, we review examples of natural shape-changing materials-skeletal muscle, tendons and plant tissues-and compare with synthetic examples with similar methods of operation. Stimuli to motion are outlined in general principle, with examples of their use and potential in manufactured systems. Anisotropy is identified as a crucial element in directing shape-change to fulfil designed tasks, and some manufacturing routes to its achievement are highlighted. We conclude with potential directions for future work, including the simultaneous development of materials and manufacturing techniques and the hierarchical combination of effects at multiple length scales.

show abstract

The diversity of hydrostatic skeletons

Cited by 202 publications

References 103 publications

A Model of Larval Biomechanics Reveals Exploitable Passive Properties for Efficient Locomotion

A Model of Larval Biomechanics Reveals Exploitable Passive Properties for Efficient Locomotion

Mechanics dictate where and how freshwater planarians fission

Morphing in nature and beyond: a review of natural and synthetic shape-changing materials and mechanisms

Contact Info

Product

Resources

About