From bouncy legs to poisoned arrows: elastic movements in invertebrates

Patek, S. N.; Dudek, Daniel; Rosario, M. V.

doi:10.1242/jeb.038596

Cited by 88 publications

(96 citation statements)

References 82 publications

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“…However, that does not mean that links 2 and 4 are not mechanically important. Both the meral-V (link 2) and the saddle (link 4) have previously been identified as part of the elastic mechanism underlying the extreme power amplification of the appendage [28,[47][48][49]. We can hypothesize that the evolution of those components might be tied more closely with energy storage, as opposed to KT.…”

Section: (C) Mechanical Metrics and Evolutionary Analysesmentioning

confidence: 97%

Mechanical sensitivity reveals evolutionary dynamics of mechanical systems

Anderson

Patek

2015

Proc. R. Soc. B.

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A classic question in evolutionary biology is how form-function relationships promote or limit diversification. Mechanical metrics, such as kinematic transmission (KT) in linkage systems, are useful tools for examining the evolution of form and function in a comparative context. The convergence of disparate systems on equivalent metric values (mechanical equivalence) has been highlighted as a source of potential morphological diversity under the assumption that morphology can evolve with minimal impact on function. However, this assumption does not account for mechanical sensitivity-the sensitivity of the metric to morphological changes in individual components of a structure. We examined the diversification of a four-bar linkage system in mantis shrimp (Stomatopoda), and found evidence for both mechanical equivalence and differential mechanical sensitivity. KT exhibited variable correlations with individual linkage components, highlighting the components that influence KT evolution, and the components that are free to evolve independently from KT and thereby contribute to the observed pattern of mechanical equivalence. Determining the mechanical sensitivity in a system leads to a deeper understanding of both functional convergence and morphological diversification. This study illustrates the importance of multi-level analyses in delineating the factors that limit and promote diversification in form-function systems.

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Section: (C) Mechanical Metrics and Evolutionary Analysesmentioning

confidence: 97%

Mechanical sensitivity reveals evolutionary dynamics of mechanical systems

Anderson

Patek

2015

Proc. R. Soc. B.

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“…For each trial, we recorded muscle-tendon force and length as well as fascicle length (via sonomicrometry) for 200 ms, which was long enough to capture the full power stroke of the MTU during all loading conditions. We also simulated dynamic loading conditions with an anatomical 'catch' that could effectively hold the load in place while muscle contraction loaded strain energy into elastic tissues (Patek et al, 2011). To do this, we implemented a 'catch force' by enforcing the rule: a load =0 for F MTU <F catch =0.95×F o .…”

Section: In Vitro Data Collection: Dynamic Contractions In Simulated mentioning

confidence: 99%

“…Recent work suggests that frogs use a variable mechanical advantage as well as proximal-distal sequence of joint action to facilitate elastic energy storage and release (Astley and Roberts, 2014). Such 'dynamic catch mechanisms' may provide an effective alternative to the anatomical catch and trigger systems observed in many invertebrates (Patek et al, 2011).…”

Section: Empirical Versus Theoretical Limits Of Mtu Power Amplificationmentioning

confidence: 99%

“…jumping, prey capture, feeding). Many animals overcome this potential constraint by using elastic mechanisms that store the energy of muscular contraction relatively slowly, then release it rapidly to provide a brief burst of power (de Groot and van Leeuwen, 2004;Lappin et al, 2006;Deban et al, 2007;Van Wassenbergh et al, 2008;Patek et al, 2011;. In some arthropods, the storage and release of elastic energy is facilitated by an explicit anatomical 'catch' that holds an appendage in place while muscle contraction loads strain energy into elastic tissues (Gronenberg, 1996;Patek et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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Power amplification in an isolated muscle-tendon is load dependent

Sawicki

Sheppard

Roberts

2015

Journal of Experimental Biology

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During rapid movements, tendons can act like springs, temporarily storing work done by muscles and then releasing it to power body movements. For some activities, such as frog jumping, energy is released from tendon much more rapidly than it is stored, thus amplifying muscle power output. The period during which energy is loaded into a tendon by muscle work may be aided by a catch mechanism that restricts motion, but theoretical studies indicate that power can be amplified in a muscle-tendon load system even in the absence of a catch. To explore the limits of power amplification with and without a catch, we studied the bullfrog plantaris muscle-tendon during in vitro contractions. A novel servomotor controller allowed us to measure muscle-tendon unit (MTU) mechanical behavior during contractions against a variety of simulated inertial-gravitational loads, ranging from zero to 1× the peak isometric force of the muscle. Power output of the MTU system was load dependent and power amplification occurred only at intermediate loads, reaching ∼1.3× the peak isotonic power output of the muscle. With a simulated anatomical catch mechanism in place, the highest power amplification occurred at the lowest loads, with a maximum amplification of more than 4× peak isotonic muscle power. At higher loads, the benefits of a catch for MTU performance diminished sharply, suggesting that power amplification >2.5× may come at the expense of net mechanical work delivered to the load.

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“…Nevertheless, because of the existence of resilin, a certain degree of passive elasticity cannot be ruled out in the ant leg (Weis-Fogh, 1960). This long-chained protein is ideally suited as an energy store and has been found between the leg segments of several insects (Andersen, 1963;Andersen, 1964;Andersen and Weis-Fogh, 1964;Alexander, 1966;Anderson, 1966;Sannasi, 1969;Neff et al, 2000;BennetClark, 2007;Patek et al, 2011;Michels and Gorb, 2012).…”

Section: Research Articlementioning

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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From bouncy legs to poisoned arrows: elastic movements in invertebrates

Cited by 88 publications

References 82 publications

Mechanical sensitivity reveals evolutionary dynamics of mechanical systems

Mechanical sensitivity reveals evolutionary dynamics of mechanical systems

Power amplification in an isolated muscle-tendon is load dependent

Level locomotion in wood ants: evidence for grounded running

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