But would he have come up with the explanation that Gábor Horváth, Susanne Åkesson and colleagues from Hungary and Sweden have: that zebra's stripes stave off blood-sucking insects? The team publishes their discovery that zebra stripes is the least attractive hide pattern for voracious horsefiles in the Journal of Experimental Biology at http://jeb.biologists.org/.
Horseflies (tabanids) deliver nasty bites, carry disease and distract grazing animals from feeding. According to Horváth and colleagues, these insects are attracted to horizontally polarized light because reflections from water are horizontally polarized and aquatic insects use this phenomenon to identify stretches of water where they can mate and lay eggs.
However, blood-sucking female tabanids are also guided to victims by linearly polarized light reflected from their hides. Explaining that horseflies are more attracted to dark horses than to white horses, the team also points out that developing zebra embryos start out with a dark skin, but go on to develop white stripes before birth. The team wondered whether the zebra's stripy hide might have evolved to disrupt their attractive dark skins and make them less appealing to voracious bloodsuckers, such as tabanids.
Travelling to a horsefly-infested horse farm near Budapest, the team tested how attractive these blood-sucking insects found black and white stripes by varying the width, density and angle of the stripes and the direction of polarization of the light that they reflected. Trapping attracted insects with oil and glue, the team found that the striped patterns attracted fewer flies as the stripes became narrower, with the narrowest stripes attracting the fewest tabanids.
The team then tested the attractiveness of white, dark and striped horse models. Suspecting that the striped horse would attract an intermediate number of flies between the white and dark models, the team was surprised to find that the striped model was the least attractive of all.
Finally, when the team measured the stripe widths and polarization patterns of light reflected from real zebra hides, they found that the zebra's pattern correlated well with the patterns that were least attractive to horseflies.
'We conclude that zebras have evolved a coat pattern in which the stripes are narrow enough to ensure minimum attractiveness to tabanid flies', says the team and they add, 'The selection pressure for striped coat patterns as a response to blood-sucking dipteran parasites is probably high in this region [Africa]'.
IF REPORTING ON THIS STORY, PLEASE MENTION THE JOURNAL OF EXPERIMENTAL BIOLOGY AS THE SOURCE AND, IF REPORTING ONLINE, PLEASE CARRY A LINK TO: http://jeb.biologists.org
REFERENCE: Egri, Á., Blahó, M., Kriska, G., Farkas, R., Gyurkovszky, M., Åkesson, S. and Horváth, G. (2012). Polarotactic tabanids find striped patterns with brightness and/or polarization modulation least attractive: an advantage of zebra stripes. J. Exp. Biol. 215, 736-745.
This article is posted on this site to give advance access to other authorised media who may wish to report on this story. Full attribution is required, and if reporting online a link to jeb.biologists.com is also required. The story posted here is COPYRIGHTED. Therefore advance permission is required before any and every reproduction of each article in full. PLEASE CONTACT email@example.com
Colorectal cancer: Increased life expectancy thanks to individualised therapies
20.02.2020 | Christian-Albrechts-Universität zu Kiel
Sweet beaks: What Galapagos finches and marine bacteria have in common
20.02.2020 | Max-Planck-Institut für Marine Mikrobiologie
The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.
Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...
Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.
Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...
Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices
The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...
Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.
Streaming films and music, scrolling through social media, and using cloud-based storage services are everyday activities now.
After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.
"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.
12.02.2020 | Event News
16.01.2020 | Event News
15.01.2020 | Event News
21.02.2020 | Medical Engineering
21.02.2020 | Health and Medicine
21.02.2020 | Physics and Astronomy