Kinematics, hydrodynamics and force production of pleopods suggest jet-assisted walking in the American lobster (<i>Homarus americanus</i>)

Lim, Jeanette L; DeMont, M. Edwin

doi:10.1242/jeb.026922

Cited by 38 publications

(39 citation statements)

References 45 publications

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“…Interestingly, the swimming speed increases as the robot arms are confined further by the floor and the walls. Similar results have been previously reported with different type of swimmers in confinement [7,[18][19][20][21][22][23][24][25]. For instance, a microswimmer modeled as an infinite waving sheet is able to swim faster near parallel walls with an increase in the rate of working by the sheet [18].…”

Section: Discussionsupporting

confidence: 88%

“…Our experimental system offers exciting opportunities to explore additional effects in the future. For example, the Reynolds number could be increased by adjusting the angular speed of the arms to generate inertial jets of relevance to larger crustaceans crawling along a boundary [7]. However, the results must be interpreted carefully if the air-oil interface deforms substantially.…”

Section: Discussionmentioning

confidence: 99%

“…A diversity of organisms rely on the coordination of multiple appendages for locomotion. Examples include various crustaceans such as copepods [1], remipedes [2], krill [3,4], crabs [5], and lobsters [6,7]. There is commonly a phase delay between the oscillation of adjacent appendages, which collectively produce a rhythm referred to as a metachronal wave [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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Metachronal Swimming with Rigid Arms near Boundaries

Hayashi

Takagi

2020

Fluids

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Various organisms such as crustaceans use their appendages for locomotion. If they are close to a confining boundary then viscous as opposed to inertial effects can play a central role in governing the dynamics. To study the minimal ingredients needed for swimming without inertia, we built an experimental system featuring a robot equipped with a pair of rigid slender arms with negligible inertia. Our results show that directing the arms to oscillate about the same time-averaged orientation produces no net displacement of the robot each cycle, regardless of any phase delay between the oscillating arms. The robot is able to swim if the arms oscillate asynchronously around distinct orientations. The measured displacement over time matches well with a mathematical model based on slender-body theory for Stokes flow. Near a confining boundary, the robot with no net displacement every cycle showed similar behavior, while the swimming robot increased in speed closer to the boundary.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Metachronal Swimming with Rigid Arms near Boundaries

Hayashi

Takagi

2020

Fluids

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“…Unlike the study by Patria and Wiese (Patria and Wiese, 2004), the larger species (E. superba) did not produce vortex rings from the side view, which suggests that the observed vortex rings were an artifact of the aquarium or tethering in their study. Vortex rings were also not produced in the flow field of a model lobster (235mm body length) performing pleopod swimming (Lim and DeMont, 2009), thus suggesting that vortex rings may not form, even at larger Reynolds numbers. Patria and Wiese identified the vortex as a potential benefit to propulsion because well positioned krill could take advantage of regions of flow disturbances that have an upward and forward moving component (Patria and Wiese, 2004).…”

Section: Flow Fieldsmentioning

confidence: 98%

The hydrodynamic disturbances of two species of krill: implications for aggregation structure

Catton

Webster

Kawaguchi

et al. 2011

Journal of Experimental Biology

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Swimming capacity is dependent on size (Johnson and Tarling, 2008) and organism size is directly related to the spatial extent of the hydrodynamic disturbance, which potentially provides a sensory field for prey, predators and conspecifics (Abrahamsen et al., 2010 Accepted 15 February 2011 SUMMARY Krill aggregations vary in size, krill density and uniformity depending on the species of krill. These aggregations may be structured to allow individuals to sense the hydrodynamic cues of neighboring krill or to avoid the flow fields of neighboring krill, which may increase drag forces on an individual krill. To determine the strength and location of the flow disturbance generated by krill, we used infrared particle image velocimetry measurements to analyze the flow field of free-swimming solitary specimens (Euphausia superba and Euphausia pacifica) and small, coordinated groups of three to six E. superba. Euphausia pacifica individuals possessed shorter body lengths, steeper body orientations relative to horizontal, slower swimming speeds and faster pleopod beat frequencies compared with E. superba. The downward-directed flow produced by E. pacifica has a smaller maximum velocity and smaller horizontal extent of the flow pattern compared with the flow produced by E. superba, which suggests that the flow disturbance is less persistent as a potential hydrodynamic cue for E. pacifica. Time record analysis reveals that the hydrodynamic disturbance is very weak beyond two body lengths for E. pacifica, whereas the hydrodynamic disturbance is observable above background level at four body lengths for E. superba. Because the nearest neighbor separation distance of E. superba within a school is less than two body lengths, hydrodynamic disturbances are a viable cue for intraspecies communication. The orientation of the position of the nearest neighbor is not coincident with the orientation of the flow disturbance, however, which indicates that E. superba are avoiding the region of strongest flow.

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“…Hence, the fluid dynamics of cilia beating are significantly different from the fluid dynamics of crustacean swimming. Relatively few studies have examined metachronal limb paddling for the range of Re under which crustaceans operate (28)(29)(30). Recently, a model based on drag forces alone predicted a slight mechanical advantage of metachronal wave in krill swimming (31).…”

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confidence: 99%

Neural mechanism of optimal limb coordination in crustacean swimming

Zhang¹,

Guy²,

Mulloney

et al. 2014

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

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A fundamental challenge in neuroscience is to understand how biologically salient motor behaviors emerge from properties of the underlying neural circuits. Crayfish, krill, prawns, lobsters, and other long-tailed crustaceans swim by rhythmically moving limbs called swimmerets. Over the entire biological range of animal size and paddling frequency, movements of adjacent swimmerets maintain an approximate quarter-period phase difference with the more posterior limbs leading the cycle. We use a computational fluid dynamics model to show that this frequency-invariant stroke pattern is the most effective and mechanically efficient paddling rhythm across the full range of biologically relevant Reynolds numbers in crustacean swimming. We then show that the organization of the neural circuit underlying swimmeret coordination provides a robust mechanism for generating this stroke pattern. Specifically, the wave-like limb coordination emerges robustly from a combination of the half-center structure of the local central pattern generating circuits (CPGs) that drive the movements of each limb, the asymmetric network topology of the connections between local CPGs, and the phase response properties of the local CPGs, which we measure experimentally. Thus, the crustacean swimmeret system serves as a concrete example in which the architecture of a neural circuit leads to optimal behavior in a robust manner. Furthermore, we consider all possible connection topologies between local CPGs and show that the natural connectivity pattern generates the biomechanically optimal stroke pattern most robustly. Given the high metabolic cost of crustacean swimming, our results suggest that natural selection has pushed the swimmeret neural circuit toward a connection topology that produces optimal behavior. locomotion | coupled oscillators | phase locking | metachronal waves I t is widely believed that neural circuits have evolved to optimize behavior that increases reproductive fitness. Despite this belief, few studies have clearly identified the neural mechanisms producing optimal behaviors. The complexity of behaviors generally makes it difficult to assess their optimality, and neural circuits are often too complicated to concretely link neural mechanisms to the overt behavior. Energy-intensive locomotion such as steady swimming, walking, and flying provides important model systems for studying optimality because the goal of the behavior is clear and it is likely to have been optimized for efficiency (1). For example, the kinematics of locomotion has been shown to be optimal in the cases of the undulatory motion of the sandfish lizard and the lamprey (2, 3). On the other hand, the neural circuits underlying locomotion in most organisms are not sufficiently characterized to understand how they give rise to the optimal motor behavior. Because of the distinct frequency-invariant stroke pattern and the relative simplicity of the neuronal circuit, limb coordination of long-tailed crustaceans during steady swimming provides an ideal model system ...

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Kinematics, hydrodynamics and force production of pleopods suggest jet-assisted walking in the American lobster (Homarus americanus)

Cited by 38 publications

References 45 publications

Metachronal Swimming with Rigid Arms near Boundaries

Metachronal Swimming with Rigid Arms near Boundaries

The hydrodynamic disturbances of two species of krill: implications for aggregation structure

Neural mechanism of optimal limb coordination in crustacean swimming

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