Tardigrades exhibit robust interlimb coordination across walking speeds and terrains.

TitleTardigrades exhibit robust interlimb coordination across walking speeds and terrains.
Publication TypeJournal Article
Year of Publication2021
AuthorsNirody, JA, Duran, LA, Johnston, D, Cohen, DJ
JournalProc Natl Acad Sci U S A
Date Published2021 08 31
KeywordsAnimals, Biological Evolution, Biomechanical Phenomena, Image Processing, Computer-Assisted, Locomotion, Lower Extremity, Tardigrada, Video Recording, Walking, Walking Speed

<p>Tardigrades must negotiate heterogeneous, fluctuating environments and accordingly utilize locomotive strategies capable of dealing with variable terrain. We analyze the kinematics and interleg coordination of freely walking tardigrades (species: ). We find that tardigrade walking replicates several key features of walking in insects despite disparities in size, skeleton, and habitat. To test the effect of environmental changes on tardigrade locomotor control circuits we measure kinematics and interleg coordination during walking on two substrates of different stiffnesses. We find that the phase offset between contralateral leg pairs is flexible, while ipsilateral coordination is preserved across environmental conditions. This mirrors similar results in insects and crustaceans. We propose that these functional similarities in walking coordination between tardigrades and arthropods is either due to a generalized locomotor control circuit common to panarthropods or to independent convergence onto an optimal strategy for robust multilegged control in small animals with simple circuitry. Our results highlight the value of tardigrades as a comparative system toward understanding the mechanisms-neural and/or mechanical-underlying coordination in panarthropod locomotion.</p>

Alternate JournalProc Natl Acad Sci U S A
PubMed ID34446560
PubMed Central IDPMC8536314