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Ecologie physique du piège des fourmillons : une construction animale en milieu granulaire.

Abstract : Physical ecology of the antlion trap The use of tools as an aid for feeding evolved independently in several taxonomic groups. Among these tools, some animal constructions are intended to trap the preys (e.g. spider webs). The physical working of these traps remains pourly known. Web traps are especially hard to study because their architecture and mechanical properties are intricate. An antlion uses dry sand to dig a trap to catch ants. In optimal conditions, the prey is naturlly conveyed to the predator. This crater shaped trap presents a simple architecture, and is therefore ideal for understanding how traps physically work. An optimal theoretical architecture is defined as a perfectly conical crater, with a slope lower than the slope defined by the physics of sand aimed at avoiding useless avalanches. A system of three-dimensional scanning and modelling gave a fine capture of traps architecture. With this equipment, it was demonstrated that antlion traps are close to optimality. An altered trap architecture leads to an attack behaviour and a cost of predation: sand tossing to destabilize ants escaping from the trap, and bites. A biotest was created from an artificial stimulus modelling the ant footsteps on sand. This biotest has proved that antlions orientate bites and sand tossing using mechanical information propagated in sand. Thus, utilization of physical characteristics of the granular matter “sand” ensures predation efficiency. These results are discussed in an evolutionary ecology point of view.
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Submitted on : Friday, November 30, 2007 - 3:46:27 PM
Last modification on : Tuesday, January 11, 2022 - 5:56:18 PM
Long-term archiving on: : Thursday, September 27, 2012 - 10:35:24 AM


  • HAL Id : tel-00193114, version 1



A. Fertin. Ecologie physique du piège des fourmillons : une construction animale en milieu granulaire.. Ecologie, Environnement. Université François Rabelais - Tours, 2007. Français. ⟨tel-00193114⟩



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