Archer fish hunt insects with water jet 6 times stronger than their muscular power

Fish modulate water jet dynamics to increase impact to prey

2012-10-25

(Press-News.org) Archer fish knock their insect prey out of overhanging vegetation with a jet of water several times more powerful than the fish's muscles. New research now shows that the fish generate this power externally using water dynamics rather than with any specialized internal organs. The research, published Oct. 24 in the open access journal PLOS ONE by Alberto Vailati and colleagues from the University of Milan, provides the first explanation for how archer fish can generate such powerful jets to capture their prey.

Other animals like chameleons and salamanders store energy in collagen fibers in their bodies and abruptly release this stored energy to project their tongues at high speeds, but previous studies on archer fish have ruled out such specialized organs as the source of the powerful water jets.

VIDEO: This is a slow-motion movie of archer fish shooting at prey and eating it when it falls into water.
Click here for more information.

The authors of the current study used high-speed video recordings of archer fish knocking insects out of overhanging plants to study the mechanics of the water jet and found that the fish could modulate the velocity of the jet to create a single large water drop that hit the prey with a large force. According to the authors, this approach avoids the evolutionary costs needed to develop special internal structures to store these large amounts of energy.

"The origin of the effectiveness of the jet squirted by archer fish has been searched for inside of the fish for nearly 250 years. The striking finding of our work is that a large amplification of muscular power occurs outside of the fish and leads to a very powerful impact of the jet with the prey" says Vailati.

VIDEO: This is a movie of archer fish firing a flurry of blows at prey.
Click here for more information.

INFORMATION:

Citation: Vailati A, Zinnato L, Cerbino R (2012) How Archer Fish Achieve a Powerful Impact: Hydrodynamic Instability of a Pulsed Jet in Toxotes jaculatrix. PLoS ONE 7(10): e47867. doi:10.1371/journal.pone.0047867

Financial Disclosure: The authors have no support or funding to report.

Competing Interest Statement: The authors have declared that no competing interests exist.

PLEASE LINK TO THE SCIENTIFIC ARTICLE IN ONLINE VERSIONS OF YOUR REPORT (URL goes live after the embargo ends):

http://dx.plos.org/10.1371/journal.pone.0047867

[Attachments] See images for this press release:

ELSE PRESS RELEASES FROM THIS DATE:

Older adults worse at distinguishing between lifted weights than younger counterparts

2012-10-25

As we grow older, we are less capable of correctly estimating differences in the weights of objects we lift, according to a study published Oct. 24 in the open access journal PLOS ONE by Jessica Holmin and Farley Norman from North Dakota State University and Western Kentucky University, respectively. Previous studies have shown that aging is frequently associated with a decrease in muscle mass and consequently strength, making it more difficult to lift objects. As a result, older adults often perceive weights they lift as being heavier than they actually are. In the current ...

Satellite images tell tales of changing biodiversity

2012-10-25

Analysis of texture differences in satellite images may be an effective way to monitor changes in vegetation, soil and water patterns over time, with potential implications for measuring biodiversity as well, according to new research published Oct. 24 by Matteo Convertino from the University of Florida and colleagues in the open access journal PLOS ONE. The authors designed statistical models to estimate two aspects of biodiversity in satellite images: the number of species in a given region, or 'species richness', and the rate at which species entered or were removed ...

Gene mutation identifies colorectal cancer patients who live longer with aspirin therapy

2012-10-25

BOSTON—Aspirin therapy can extend the life of colorectal cancer patients whose tumors carry a mutation in a key gene, but has no effect on patients who lack the mutation, Dana-Farber Cancer Institute scientists report in the Oct. 25 issue of the New England Journal of Medicine. In a study involving more than 900 patients with colorectal cancer, the researchers found that, for patients whose tumors harbored a mutation in the gene PIK3CA, aspirin use produced a sharp jump in survival: five years after diagnosis, 97 percent of those taking aspirin were still alive, compared ...

Electronic nose could be used to detect sleep apnoea

2012-10-25

An electronic nose, used to detect the presence of molecules in the breath of a patient, could be used to diagnose obstructive sleep apnoea. A new study, published online today ahead of print (25 October 2012) in the European Respiratory Journal, could make the diagnosis of the condition quick and inexpensive compared to current methods. The gold standard used to identify sleep apnoea is an overnight sleep test. This is technically demanding, time-consuming and cost-intensive. Electronic nose devices have been shown to distinguish between a number of diseases; ...

Live cables explain enigmatic electric currents

2012-10-25

This press release is available in German. Researchers at Aarhus University, Denmark, made a sensational discovery almost three years ago when they measured electric currents in the seabed. It was unclear as to what was conducting the current, but the researchers imagined the electric currents might run between different bacteria via a joint external wiring network.The researchers have now solved the mystery. It turns out that the whole process takes place inside bacteria that are one centimetre long. They make up a kind of live electric cable that no one had ever imagined ...

Feeling hot, hot, hot

2012-10-25

We're not used to thinking of ourselves as animals. But as Jason Samson sees it, climate is as important in shaping the distribution and movement of humans as it is in other animals. The McGill-trained ecologist and fellow researchers have been using modeling techniques similar to those used to define the ecological niche for plant and animal species to explore the correlation between climate patterns and population growth in the contiguous United States between 1900-2000. And what they discovered was a pronounced population shift away from areas within the U.S. with cool ...

Astronomers report that dark matter 'halos' may contain stars, disprove other theories

2012-10-25

Could it be that dark matter "halos" — the huge, invisible cocoons of mass that envelop entire galaxies and account for most of the matter in the universe — aren't completely dark after all but contain a small number of stars? Astronomers from UCLA, UC Irvine and elsewhere make a case for that in the Oct. 25 issue of the journal Nature. Astronomers have long disagreed about why they see more light in the universe than it seems they should — that is, why the infrared light they observe exceeds the amount of light emitted from known galaxies. When looking at the cosmos, ...

Flycatchers' genomes explain how 1 species became 2

2012-10-25

Just how new species are established is still one of the most central questions in biology. In an article in the leading scientific journal Nature, researchers at Uppsala University in Sweden describe how they mapped the genomes of the European pied flycatcher and the collared flycatcher and found that it is disparate chromosome structures rather than separate adaptations in individual genes that underlies the separation of the species. "We were surprised that such a large part of the genome was nearly identical in the two species," says Hans Ellegren, professor of evolutionary ...

Parkinson's breakthough could slow disease progression

2012-10-25

CHICAGO --- In an early-stage breakthrough, a team of Northwestern University scientists has developed a new family of compounds that could slow the progression of Parkinson's disease. Parkinson's, the second most common neurodegenerative disease, is caused by the death of dopamine neurons, resulting in tremors, rigidity and difficulty moving. Current treatments target the symptoms but do not slow the progression of the disease. The new compounds were developed by Richard B. Silverman, the John Evans Professor of Chemistry at the Weinberg College of Arts and Sciences ...

Survival of the affordable care act assessed in new commentaries

2012-10-25

(Garrison, NY) As the presidential candidates clash over the fate of the Affordable Care Act, a set of seven essays by leading legal experts, economists, and scholars examines the implications of the Supreme Court's decision on the ACA and makes it clear that there is no consensus about what is economically or morally just when it comes to health care coverage in this country. The essays appear in the Hastings Center Report. While the essays provide a range of perspectives, a few common themes emerge. Foremost among them is that the individual mandate may not work as ...

Synthesis of seven quebracho indole alkaloids using "antenna ligands" in 7-10 steps, including three first-ever asymmetric syntheses

Lisbon to host world’s largest conference on ecosystem restoration in 2027, led by researcher from the Faculty of Sciences, University of Lisbon

Electrocatalysis with dual functionality – an overview

Scripps Research awarded $6.9 million by NIH to crack the code of lasting HIV vaccine protection

New post-hoc analysis shows patients whose clinicians had access to GeneSight results for depression treatment are more likely to feel better sooner

Bimodal tactile tomography with bayesian sequential palpation for intracavitary microstructure profiling and segmentation

Disrupted connectivity of the brainstem ascending reticular activating system nuclei-left parahippocampal gyrus could reveal mechanisms of delirium following basal ganglia intracerebral hemorrhage

[Press-News.org] Archer fish hunt insects with water jet 6 times stronger than their muscular power
Fish modulate water jet dynamics to increase impact to prey

Archer fish hunt insects with water jet 6 times stronger than their muscular power

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: