{"id":1510,"date":"2011-04-23T18:50:28","date_gmt":"2011-04-23T16:50:28","guid":{"rendered":"http:\/\/codexvirtualis.fr\/codex\/?p=1510"},"modified":"2021-09-02T13:47:00","modified_gmt":"2021-09-02T11:47:00","slug":"les-acrobaties-de-lescargot","status":"publish","type":"post","link":"https:\/\/codexvirtualis.fr\/codex\/les-acrobaties-de-lescargot","title":{"rendered":"Les acrobaties de l’Escargot"},"content":{"rendered":"

 <\/p>\n

\"Escargot<\/a>
Escargot des haies acrobate (Lyon, septembre 2010)<\/figcaption><\/figure>\n

 <\/p>\n

Il n’est pas rare d’observer des Escargots se d\u00e9pla\u00e7ant sur des surfaces verticales ou dans des positions improbables.
\n 
\nComment r\u00e9alisent-ils ces d\u00e9placements ?
\n 
\nComme tous les Mollusques, les Escargots poss\u00e8dent un organe impliqu\u00e9 dans la locomotion appel\u00e9 \u00ab\u00a0pied\u00a0\u00bb. Chez les Gast\u00e9ropodes, groupe dans lequel sont class\u00e9s les Escargots, cet organe prend la forme d’une sole de reptation. Les animaux se d\u00e9placent en glissant, leur pied restant au contact du support.
\n 
\nLa locomotion est r\u00e9alis\u00e9e gr\u00e2ce \u00e0 la propagation d’une onde de contraction le long du pied.
\nDans le cas d’un d\u00e9placement sur une surface pentue, la contraction d\u00e9bute \u00e0 l’arri\u00e8re du pied et progresse vers l’avant. <\/p>\n

La contraction d’une zone du pied permet \u00e0 celle-ci d’avancer dans la mesure o\u00f9 l’arri\u00e8re de la zone se rapproche de l’avant qui reste fixe. Ce dernier se d\u00e9place au moment de la contraction de la r\u00e9gion du pied juste ant\u00e9rieure.
\n 
\nL’Escargot adh\u00e8re \u00e0 la surface sur laquelle il se tient gr\u00e2ce \u00e0 une substance appel\u00e9e mucus, s\u00e9cr\u00e9t\u00e9e par une glande localis\u00e9e au niveau du pied. <\/p>\n

Le mucus a une consistance de gel et joue le r\u00f4le de colle. Il est compos\u00e9 principalement d’eau et de sels min\u00e9raux mais il contient \u00e9galement de longues prot\u00e9ines qui \u00e9tablissent des liaisons entre elles et forment ainsi un r\u00e9seau aux propri\u00e9t\u00e9s \u00e9lastiques. <\/p>\n

Au niveau de la zone du pied qui se contracte, les forces exerc\u00e9es sur le mucus rompent les liaisons entre les prot\u00e9ines, rendant le mucus liquide. Ce changement de consistance r\u00e9duit localement l’adh\u00e9rence au support et permet le d\u00e9placement de la zone contract\u00e9e du pied. <\/p>\n

Lorsque la contraction cesse, les forces exerc\u00e9es sur le mucus sont r\u00e9duites et les liaisons entre prot\u00e9ines sont reform\u00e9es, restaurant l’adh\u00e9rence au support.
\n 
\nLes acrobaties de l’Escargot, d\u00e9placements sur des surfaces pentues, sont donc possibles gr\u00e2ce \u00e0 la propagation d’ondes de contraction du pied r\u00e9alis\u00e9e en pr\u00e9sence d’un mucus thixotrope, alternativement solide collant et liquide coulant.
\n 
\nLorsqu’il \u00e9volue sur un support horizontal, l’Escargot emploie une technique moins co\u00fbteuse en \u00e9nergie.<\/p>\n

Des ondulations de la face inf\u00e9rieure du pied, au contact du support, se propagent de l’avant vers l’arri\u00e8re. Dans les r\u00e9gions o\u00f9 la zone de contact entre le pied et le support est faible, la pression dans le mucus est plus \u00e9lev\u00e9e que dans les autres r\u00e9gions. En cons\u00e9quence, le mucus s’\u00e9coule de l’avant vers l’arri\u00e8re.<\/p>\n

En r\u00e9action \u00e0 l’\u00e9coulement et en relation avec la viscosit\u00e9 du mucus, le support exerce une force de r\u00e9action orient\u00e9e vers l’avant, qui est transmise au pied et fait progresser l’animal.<\/p>\n

 
\nPour en savoir plus, consultez l’article<\/p>\n

Courty J.M. et Kierlik E., 2009 \u2013 Avancer comme un escargot. Pour la Science, n\u00b0378\u00a0: 94-96.
\n 
\nPour acc\u00e9der au site de la revue Pour la science<\/a> (adresse http:\/\/www.pourlascience.fr)
\n 
\nPour consulter les images d’Escargots et autres Mollusques<\/a> des parcs de Gerland et des berges du Rh\u00f4ne
\n <\/p>\n

\n","protected":false},"excerpt":{"rendered":"

    Il n’est pas rare d’observer des Escargots se d\u00e9pla\u00e7ant sur des surfaces verticales ou dans des positions improbables.   Comment r\u00e9alisent-ils ces d\u00e9placements ?   Comme tous les Mollusques, les Escargots poss\u00e8dent un organe impliqu\u00e9 dans la locomotion appel\u00e9 \u00ab\u00a0pied\u00a0\u00bb. Chez les Gast\u00e9ropodes, groupe dans lequel sont class\u00e9s les Escargots, cet organe prend […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[7],"tags":[12,22,13,11],"class_list":["post-1510","post","type-post","status-publish","format-standard","hentry","category-images-insolites-instructives","tag-mollusque","tag-physiologie","tag-plan-dorganisation","tag-publication"],"aioseo_notices":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/1510","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/comments?post=1510"}],"version-history":[{"count":24,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/1510\/revisions"}],"predecessor-version":[{"id":14247,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/posts\/1510\/revisions\/14247"}],"wp:attachment":[{"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/media?parent=1510"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/categories?post=1510"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/codexvirtualis.fr\/codex\/wp-json\/wp\/v2\/tags?post=1510"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}