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2021-06-22 - Colloque/Présentation - poster - Anglais - page(s)

Deridoux Amandine , Flammang Patrick , Gabriele Sylvain , "Mechanical description of the podia in sea star locomotion" in 5th International Conference on Physics & Biological Systems 2021, Fully online, France, 2021

  • Codes CREF : Biologie (DI3100), Chimie (DI1300)
  • Unités de recherche UMONS : Biologie des Organismes Marins et Biomimétisme (S864), Laboratoire Interfaces et Fluides complexes (S885)
  • Instituts UMONS : Institut de Recherche en Science et Ingénierie des Matériaux (Matériaux), Institut des Biosciences (Biosciences)
  • Centres UMONS : Centre d’Innovation et de Recherche en Matériaux Polymères (CIRMAP)
Texte intégral :

Abstract(s) :

(Anglais) Sea stars use a multitude of small hydraulic organs (i.e., the tube feet or podia), to locomote, to strongly attach to the surrounding, and to pry open the mussels on which they feed. Podia are secretory organs in which two types of adhesive cells co-secrete a blend of adhesive proteins to form the adhesive layer joining the podia to the substrate (1). Despite the paramount importance of podia in sea star locomotion, the regulation of the number of podia sticking to a surface during movement is still poorly understood. To address this challenge, we built up an aquarium equipped with a total internal reflection (TIRF) system and developed a robust thresholding technique for quantifying the number of podia sticking to the substrate during locomotion. We found that the contact area of individual podia increases to become a perfect circle during the adhesion phase. Surprisingly, we measured a very low percentage of podia in contact with the substrate during locomotion in Asterias rubens. Moreover, the number of sticking podia, as well as the instantaneous speed remain constant during movement. Contrary to what is observed in other animals, it seems that the size of Asterias rubens has no impact on the mean crawling speed. In contrast, we found that this speed decreases with the increase of the podial adhesion time and the increase of the number of sticking podia. A long-term goal for this project is to develop a biomechanical model of sea star locomotion based on the measurement of the adhesion energy exerted by a sea star according to the number of sticking podia.