An isolated insect leg's passive recovery from dorso-ventral perturbations

Dudek, Daniel

doi:10.1242/jeb.008367

Cited by 19 publications

(15 citation statements)

References 44 publications

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“…Nevertheless, this is considered an overestimate of energy storage and return in this system and it is assumed that in reality these springs only contribute marginally in improving energetic efficiency in cockroaches (Patek et al, 2011). It is more likely that the leg springs function as a kind of shock absorber, which responds to perturbations more quickly than a neural signal could (Koditschek et al, 2004;Dudek and Full, 2006;Dudek and Full, 2007). Thus, locomotion can be stabilised by elastic legs.…”

Section: Elastic Elements In the Insect Legmentioning

confidence: 99%

Level locomotion in wood ants: evidence for grounded running

Reinhardt

Blickhan

2014

Journal of Experimental Biology

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In order to better understand the strategies of locomotion in small insects, we have studied continuous level locomotion of the wood ant species Formica polyctena. We determined the three-dimensional centre of mass kinematics during the gait cycle and recorded the ground reaction forces of single legs utilising a self-developed test site. Our findings show that the animals used the same gait dynamics across a wide speed range without dissolving the tripodal stride pattern. To achieve higher velocities, the ants proportionally increased stride length and stepping frequency. The centre of mass energetics indicated a bouncing gait, in which horizontal kinetic and gravitational potential energy fluctuated in close phase. We determined a high degree of compliance especially in the front legs, as the effective leg length was nearly halved during the contact phase. This leads to only small vertical oscillations of the body, which are important in maintaining ground contact. Bouncing gaits without aerial phases seem to be a common strategy in small runners and can be sufficiently described by the bipedal spring-loaded inverted pendulum model. Thus, with our results, we provide evidence that wood ants perform 'grounded running'.

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Section: Elastic Elements In the Insect Legmentioning

confidence: 99%

Level locomotion in wood ants: evidence for grounded running

Reinhardt

Blickhan

2014

Journal of Experimental Biology

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“…Perturbation studies of the isolated legs of B. discoidalis give us insight into how these femoral extensors may be contributing to mechanical feedback. Dudek and Full (Dudek and Full, 2007) imposed large, dorsal-ventrally directed impulsive perturbations to isolated hindlegs. These sagittal plane perturbations were out of the plane of coxa-femur joint rotation, so any response resulted from the passive properties of the exoskeleton alone.…”

Section: System Level Perturbationsmentioning

confidence: 99%

“…(Watson et al, 2002a;Watson et al, 2002b). Control of running on rough terrain control relies on stride-to-stride neural feedback to set the general activation 'state' of the control modalities, while rejecting moderate within-stride perturbations with rapid mechanical feedback in these modalites that might include damping (Dudek and Full, 2007), energy exchange (Ahn et al, 2006;Full et al, 2002), energy storage and return (Dudek and Full, 2006), distributed contact (Spagna et al, 2007) and/or momentum trading Kubow and Full, 1999;Seipel and Holmes, 2006).…”

Section: Running Speed and Perturbation Sizementioning

confidence: 99%

Neuromechanical response of musculo-skeletal structures in cockroaches during rapid running on rough terrain

Sponberg

Full

2008

Journal of Experimental Biology

188

243

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SUMMARYA musculo-skeletal structure can stabilize rapid locomotion using neural and/or mechanical feedback. Neural feedback results in an altered feedforward activation pattern, whereas mechanical feedback using visco-elastic structures does not require a change in the neural motor code. We selected musculo-skeletal structures in the cockroach (Blaberus discoidalis) because their single motor neuron innervation allows the simplest possible characterization of activation. We ran cockroaches over a track with randomized blocks of heights up to three times the animalʼs ʻhipʼ (1.5·cm), while recording muscle action potentials (MAPs) from a set of putative control musculo-skeletal structures (femoral extensors 178 and 179). Animals experienced significant perturbations in body pitch, roll and yaw, but reduced speed by less than 20%. Surprisingly, we discovered no significant difference in the distribution of the number of MAPs, the interspike interval, burst phase or interburst period between flat and rough terrain trials. During a few very large perturbations or when a single leg failed to make contact throughout stance, neural feedback was detectable as a phase shift of the central rhythm and alteration of MAP number. System level responses of appendages were consistent with a dominant role of mechanical feedback. Duty factors and gait phases did not change for cockroaches running on flat versus rough terrain. Cockroaches did not use a follow-the-leader gait requiring compensatory corrections on a step-by-step basis. Arthropods appear to simplify control on rough terrain by rapid running that uses kinetic energy to bridge gaps between footholds and distributed mechanical feedback to stabilize the body.

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“…Isolated Periplaneta, Blaberus, and Carcinus legs passively return to constant postures after perturbation (Fourtner, 1981;Yox et al, 1982;Dudek and Full, 2007). However, the Periplaneta and Carcinus leg positions relative to gravity were unspecified and the Blaberus legs were arranged horizontally "to remove the effect of gravity from the leg response" [Dudek and Full (2007), p 3211].…”

Section: Gravity-independent Rest Positions and Muscle Passive Force mentioning

confidence: 99%

“…However, the Periplaneta and Carcinus leg positions relative to gravity were unspecified and the Blaberus legs were arranged horizontally "to remove the effect of gravity from the leg response" [Dudek and Full (2007), p 3211]. Whether these returns were gravity independent was thus unknown.…”

Section: Gravity-independent Rest Positions and Muscle Passive Force mentioning

confidence: 99%

Neural Control of Unloaded Leg Posture and of Leg Swing in Stick Insect, Cockroach, and Mouse Differs from That in Larger Animals

Hooper¹,

Guschlbauer²,

Blümel³

et al. 2009

J. Neurosci.

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Stick insect (Carausius morosus) leg muscles contract and relax slowly. Control of stick insect leg posture and movement could therefore differ from that in animals with faster muscles. Consistent with this possibility, stick insect legs maintained constant posture without leg motor nerve activity when the animals were rotated in air. That unloaded leg posture was an intrinsic property of the legs was confirmed by showing that isolated legs had constant, gravity-independent postures. Muscle ablation experiments, experiments showing that leg muscle passive forces were large compared with gravitational forces, and experiments showing that, at the rest postures, agonist and antagonist muscles generated equal forces indicated that these postures depended in part on leg muscles. Leg muscle recordings showed that stick insect swing motor neurons fired throughout the entirety of swing. To test whether these results were specific to stick insect, we repeated some of these experiments in cockroach (Periplaneta americana) and mouse. Isolated cockroach legs also had gravityindependent rest positions and mouse swing motor neurons also fired throughout the entirety of swing. These data differ from those in human and horse but not cat. These size-dependent variations in whether legs have constant, gravity-independent postures, in whether swing motor neurons fire throughout the entirety of swing, and calculations of how quickly passive muscle force would slow limb movement as limb size varies suggest that these differences may be caused by scaling. Limb size may thus be as great a determinant as phylogenetic position of unloaded limb motor control strategy.

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An isolated insect leg's passive recovery from dorso-ventral perturbations

Cited by 19 publications

References 44 publications

Level locomotion in wood ants: evidence for grounded running

Level locomotion in wood ants: evidence for grounded running

Neuromechanical response of musculo-skeletal structures in cockroaches during rapid running on rough terrain

Neural Control of Unloaded Leg Posture and of Leg Swing in Stick Insect, Cockroach, and Mouse Differs from That in Larger Animals

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