How archer fish achieve a powerful impact: hydrodynamic instability of a pulsed jet in Toxotes jaculatrix.

Archer fish knock down insects anchored to vegetation by hitting them with a precisely aimed jet of water. The striking force of the jet at the impact is such to overcome the strong anchoring forces of insects. The origin of the effectiveness of such hunting mechanism has been long searched for insi...

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Autores principales:	Alberto Vailati, Luca Zinnato, Roberto Cerbino
Formato:	article
Lenguaje:	EN
Publicado:	Public Library of Science (PLoS) 2012
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/73868a2a10f345d487b20b50a2a812bc
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spelling	oai:doaj.org-article:73868a2a10f345d487b20b50a2a812bc2021-11-18T08:11:09ZHow archer fish achieve a powerful impact: hydrodynamic instability of a pulsed jet in Toxotes jaculatrix.1932-620310.1371/journal.pone.0047867https://doaj.org/article/73868a2a10f345d487b20b50a2a812bc2012-01-01T00:00:00Zhttps://www.ncbi.nlm.nih.gov/pmc/articles/pmid/23112861/?tool=EBIhttps://doaj.org/toc/1932-6203Archer fish knock down insects anchored to vegetation by hitting them with a precisely aimed jet of water. The striking force of the jet at the impact is such to overcome the strong anchoring forces of insects. The origin of the effectiveness of such hunting mechanism has been long searched for inside of the fish, in the unsuccessful attempt to identify internal structures dedicated to the amplification of muscular power. Here we perform a kinematic analysis of the jet emitted by two specimens of Toxotes jaculatrix. We estimate that at the impact the jet conveys a typical specific power of about 3000 W/kg, which is well above the maximum specific power of the order of 500 W/kg deliverable by a vertebrate muscle. Unexpectedly, we find that the amplification of muscular power occurs outside of the fish, and is due to a hydrodynamic instability of the jet akin to those occurring in Drop-on-Demand inkjet printing. The investigated fish are found to modulate the velocity of the jet at the orifice to favor the formation of a single, large, water drop that hits the prey abruptly with a large momentum. The observed mechanism represents a remarkable example of use of an external hydrodynamic lever that does possibly not entail the high evolutionary cost needed for the development of highly specialized internal structures dedicated to the storing of mechanical energy.Alberto VailatiLuca ZinnatoRoberto CerbinoPublic Library of Science (PLoS)articleMedicineRScienceQENPLoS ONE, Vol 7, Iss 10, p e47867 (2012)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Alberto Vailati Luca Zinnato Roberto Cerbino How archer fish achieve a powerful impact: hydrodynamic instability of a pulsed jet in Toxotes jaculatrix.
description	Archer fish knock down insects anchored to vegetation by hitting them with a precisely aimed jet of water. The striking force of the jet at the impact is such to overcome the strong anchoring forces of insects. The origin of the effectiveness of such hunting mechanism has been long searched for inside of the fish, in the unsuccessful attempt to identify internal structures dedicated to the amplification of muscular power. Here we perform a kinematic analysis of the jet emitted by two specimens of Toxotes jaculatrix. We estimate that at the impact the jet conveys a typical specific power of about 3000 W/kg, which is well above the maximum specific power of the order of 500 W/kg deliverable by a vertebrate muscle. Unexpectedly, we find that the amplification of muscular power occurs outside of the fish, and is due to a hydrodynamic instability of the jet akin to those occurring in Drop-on-Demand inkjet printing. The investigated fish are found to modulate the velocity of the jet at the orifice to favor the formation of a single, large, water drop that hits the prey abruptly with a large momentum. The observed mechanism represents a remarkable example of use of an external hydrodynamic lever that does possibly not entail the high evolutionary cost needed for the development of highly specialized internal structures dedicated to the storing of mechanical energy.
format	article
author	Alberto Vailati Luca Zinnato Roberto Cerbino
author_facet	Alberto Vailati Luca Zinnato Roberto Cerbino
author_sort	Alberto Vailati
title	How archer fish achieve a powerful impact: hydrodynamic instability of a pulsed jet in Toxotes jaculatrix.
title_short	How archer fish achieve a powerful impact: hydrodynamic instability of a pulsed jet in Toxotes jaculatrix.
title_full	How archer fish achieve a powerful impact: hydrodynamic instability of a pulsed jet in Toxotes jaculatrix.
title_fullStr	How archer fish achieve a powerful impact: hydrodynamic instability of a pulsed jet in Toxotes jaculatrix.
title_full_unstemmed	How archer fish achieve a powerful impact: hydrodynamic instability of a pulsed jet in Toxotes jaculatrix.
title_sort	how archer fish achieve a powerful impact: hydrodynamic instability of a pulsed jet in toxotes jaculatrix.
publisher	Public Library of Science (PLoS)
publishDate	2012
url	https://doaj.org/article/73868a2a10f345d487b20b50a2a812bc
work_keys_str_mv	AT albertovailati howarcherfishachieveapowerfulimpacthydrodynamicinstabilityofapulsedjetintoxotesjaculatrix AT lucazinnato howarcherfishachieveapowerfulimpacthydrodynamicinstabilityofapulsedjetintoxotesjaculatrix AT robertocerbino howarcherfishachieveapowerfulimpacthydrodynamicinstabilityofapulsedjetintoxotesjaculatrix
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How archer fish achieve a powerful impact: hydrodynamic instability of a pulsed jet in Toxotes jaculatrix.

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