Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Overbearing colored light may reveal a second mechanism by which birds interpret magnetic signals

23.08.2005


Magnetic orientation is critical to the migratory success of many bird species. By studying the influence of light on the ability of migratory birds to orient to magnetic signals, researchers have found clues to suggest that birds’ orientation abilities may be more complex than previously thought and that birds may be able to interpret magnetic signals by more than one mechanism. The work is reported in Current Biology by a team including Thorsten Ritz, of the University of California, Irvine, and Wolfgang and Roswitha Wiltschko, of the University of Frankfurt, Germany.



It has been known for many years that birds possess a magnetic "inclination compass," which essentially allows birds to obtain directional information from the magnetic field by interpreting the angle of magnetic-field lines with regard to the horizon rather than by interpreting the magnetic field’s polarity. Previous work by Dr. Ritz had suggested that in interpreting magnetic signals, birds employed a so-called chemical compass that worked by way of chemical reactions in specialized photopigments in their eyes. The chemical-compass idea implied that magnetoreception was light dependent, and this possibility was subsequently given support by work from the Wiltschko team showing that the orientation of European robins, a night-migrating species, was influenced by the intensity of light in the blue-green spectrum.

In the present study, the Ritz and Wiltschko groups teamed up to analyze the orientation behavior under turquoise light in detail and revealed an unexpected phenomenon: Increasing the intensity of turquoise light changes the birds’ orientation significantly, in comparison to dimmer light levels. The researchers found that in dim turquoise light, similar to that found about 33 minutes after sunset, the birds show normal migratory orientation, with the seasonal shift between southerly directions in autumn and northerly directions in spring. Tests under specific magnetic conditions clearly showed that this orientation involved the inclination compass and suggested that it is based on the type of "chemical compass" processes predicted by the Ritz model.


However, the researchers also found that under brighter turquoise light, corresponding to light levels found 20 min after sunset, the birds still orient by the magnetic field, but they no longer show the seasonal change between spring and autumn and instead head north in both seasons. This behavior did not appear to involve the normal inclination-compass and chemical-compass mechanisms.

The new findings show that bright-colored light interferes with magnetoreception such that migratory birds can no longer obtain the information required to head into their migratory direction. The findings point to the existence of two distinct mechanisms of mechanoreception in the birds--an inclination compass and a polarity-driven compass. It is especially intriguing that under some conditions, birds appear to switch to the polarity-type magnetic response, which is based on a mechanism of a very different nature than that thought to contribute to the inclination mechanism.

Heidi Hardman | EurekAlert!
Further information:
http://www.current-biology.com
http://www.cell.com

More articles from Life Sciences:

nachricht A novel socio-ecological approach helps identifying suitable wolf habitats
17.02.2017 | Universität Zürich

nachricht New, ultra-flexible probes form reliable, scar-free integration with the brain
16.02.2017 | University of Texas at Austin

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Switched-on DNA

20.02.2017 | Materials Sciences

Second cause of hidden hearing loss identified

20.02.2017 | Health and Medicine

Prospect for more effective treatment of nerve pain

20.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>