Effect of temperature on leg kinematics in sprinting tarantulas (<i>Aphonopelma hentzi</i>): high speed may limit hydraulic joint actuation

Booster, N. A.; Su, Francis; Adolph, Stephen C.; Ahn, Anna

doi:10.1242/jeb.111922

Cited by 25 publications

(12 citation statements)

References 50 publications

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“…Spider locomotion is particularly sensitive to temperature variations (Booster et al, 2015). The room in which the experiment was conducted was heated and air conditioned.…”

Section: Data Collectionmentioning

confidence: 99%

Limping following limb loss increases locomotor stability

Wilshin

Shamble

Hovey

et al. 2018

Journal of Experimental Biology

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Although many arthropods have the ability to voluntarily lose limbs, how these animals rapidly adapt to such an extreme perturbation remains poorly understood. It is thought that moving with certain gaits can enable efficient, stable locomotion; however, switching gaits requires complex information flow between and coordination of an animal's limbs. We show here that upon losing two legs, spiders can switch to a novel, more statically stable gait, or use temporal adjustments without a gait change. The resulting gaits have higher overall static stability than the gaits that would be imposed by limb loss. By decreasing the time spent in a low-stability configuration - effectively 'limping' over less-stable phases of the stride - spiders increased the overall stability of the less statically stable gait with no observable reduction in speed, as compared with the intact condition. Our results shed light on how voluntary limb loss could have persisted evolutionarily among many animals, and provide bioinspired solutions for robots when they break or lose limbs.

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“…Spider locomotion is particularly sensitive to temperature variations (Booster et al, 2015). The room in which the experiment was conducted was heated and air conditioned.…”

Section: Data Collectionmentioning

confidence: 99%

Limping following limb loss increases locomotor stability

Wilshin

Shamble

Hovey

et al. 2018

Journal of Experimental Biology

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“…As for orb-weavers, the fact that an ambusher spider waits for its prey can result in a difference between the body temperature of the predator and the prey thus being advantageous for the flying insect. Booster et al (2015) hypothesized that at lower temperatures, the movement of the spider leg joints could be less coupled because of increased hemolymph viscosity thus slowing the flow of hemolymph, and demonstrated that at high temperature the spiders ran the fastest with the highest stride Fig. 4.…”

Section: Bioecological Interpretation Of the Effect Of Temperature Onmentioning

confidence: 99%

A simulation-based method to compare the pest suppression potential of predators: A case study with spiders

et al. 2018

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A B S T R A C TAssessing and comparing the pest killing capacity of predators is a crucial but laborious task during the implementation of sustainable farming systems. Critical attributes of assessment include quantifying predator's attack rate (a) and handling time (T h ). The maximum attack rate (T/T h ) (i.e. the maximum number of prey that can be attacked by a predator during the time interval (T) considered) could be a more precise and interpretable indicator of the potential suppression of pests exerted by a predator; however, its calculation only provides a point estimator usually derived from incomplete datasets (e.g. unbalanced or low replicated experimental designs) that could lead to draw wrong conclusions. We introduce simaR (simulation of maximum attack rates using R), an R library that generates 95% confidence intervals around estimates of the maximum attack rate that can be easily and intuitively used to compare across species. We validated the simulation method and used the empirical results of a controlled laboratory experiment to compare the maximum attack rates of spiders across a range of Medfly prey densities and illustrate how to use simaR with non-replicated partial data. Applying our method we found a significant effect of temperature on the maximum attack rate of two different guilds of spiders, the orb-weaver A. cucurbitina and the ambusher S. globosum that was not relevant regarding their attack rate and handling time. Our method compares different predator species and/or experimental conditions in a simple and reproducible procedure through an accurate, easy-to-use, fast and statistically robust analysis, based on simulation and bootstrapping, that can be used to assess the pest suppression potential of predators by simulating their functional responses from low-effort laboratory trials.

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“…In E. weijenberghi, the F S resulted to be the main determinant factor of the speed changes, at least within the limited range we studied. This result agrees with previous findings in other tarantulas (Anderson & Prestwich, 1985;Booster et al, 2015).…”

Section: Gait Patternsupporting

confidence: 94%

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Supplemental Information 1: Kinematic Data Files

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Background: For males of several terrestrial spiders the reproductive success depends to their locomotors performances. However, their mechanics of locomotion has been scarcely investigated. Aim of this work was to describe the gait patterns, analyse the gait parameters, the mechanics of locomotion and the energy saving mechanisms of Eupalaestrus weijenberghi (Araneae, Theraphosidae) on different inclinations and surfaces. Methods: Tarantulas were collected and marked for kinematic analysis. Free displacements, both at level and on incline, were recorded using two different experimental surfaces: glass and Teflon. Body segments of the experimental animals have been measured, weighted and their centre of mass experimentally determined. Through the reconstruction of trajectories of the body segments, we estimate the mechanical internal and external works and analysed the gait patterns. Results: Four gait patterns have been described, but spiders mainly employed a walk-trot-like gait. Significant differences between the first two pairs and the second two pairs were detected. No significant differences were detected among different planes or surfaces in duty factor, time lags, stride frequency and stride length. However, postural changes were observed on slippery surfaces. The mechanical work at level was lower than expected. In all conditions, the external work, and within it the vertical work, accounted for almost all the total mechanical work. The internal work was extremely low, and did not increase with gradient. Discussion: Our results support the idea of the two quadrupeds in series: the anterior composed by the first two pairs of limbs, with more explorative and steering purpose, and the posterior more involved in supporting the body weight. The mechanical work to move one unit mass a unit distance is almost constant among the different species. However spiders show lower values than expected. Minimizing the mechanical work could help to limit the metabolic energy expenditure that, in small animals, is relatively very high. However, the energy recovery due to the inverted pendulum mechanics only account for a small part of energy saving. Adhesive setae present in the tarsal, scopulae and claw tufts, would participate in different ways during different moments of the step cycle, compensating part of the energetic cost on gradient, and helping to maintain constant the gait parameters.

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Effect of temperature on leg kinematics in sprinting tarantulas (Aphonopelma hentzi): high speed may limit hydraulic joint actuation

Cited by 25 publications

References 50 publications

Limping following limb loss increases locomotor stability

Limping following limb loss increases locomotor stability

A simulation-based method to compare the pest suppression potential of predators: A case study with spiders

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