Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tropical birds sensitive to environmental cues that can be impacted by global warming

12.11.2004


Research provides information on brain changes that affect breeding in birds



A bird’s song is music to our ears -- and to the ears of his potential mates -- and a warning to other males to stay out of his territory. To Ignacio Moore, assistant professor of biology at Virginia Tech, bird songs were a curiosity that made him want to find out why birds sang at some times and not at others, at some places and not elsewhere.

Moore and University of Washington, Seattle, researchers John C. Wingfield in biology and Eliot A. Brenowitz in psychology, looked at seasonal changes in the brains of birds that account for their singing, which is a part of the male mating behavior. In the Nov. 10 issue of The Journal of Neuroscience, the official journal of the Society for Neuroscience, they report that birds in high latitudes are driven to sing by seasonal changes in the length of the day, which causes changes in the song-control nuclei of the brain. However, in the tropics, where the day length does not vary much by season, the propensity for birds to sing still changes, but is driven by environmental cues that vary by locale -- a fact that could mean those birds are more susceptible to global warming than birds in higher latitudes.


Correct timing of breeding is necessary for reproductive success, Moore said. Research by others has shown that testosterone is the main physiological cue regulating seasonal changes in the neural song-control system. Seasonal changes in the song-control system have been demonstrated by other scientists in all northern latitude species that have been investigated. But no one had researched whether seasonal changes occurred in the brains of birds in tropical areas where day-length changes are minimal. "We think it’s probably still testosterone that causes tropical birds to sing, but that the environmental cue is different," Moore said. The scientists wanted to determine whether "seasonal changes in brain structure can be mediated by local environmental cues."

Moore and his colleagues looked at two populations of the rufous-collared sparrow only 25 km apart. The two populations are at the same latitude but are on the east and west slopes of the Andes, which have very different climate patterns. "At the time of year when birds in the Papallacta population were breeding (August to September), birds in Pintag were in nonbreeding state," the researchers wrote in The Journal of Neuroscience ("Plasticity of the Avian Song Control System in Response to Localized Environmental Cues in an Equatorial Songbird"). "Correspondingly, the song control nuclei were fully grown in the breeding Papallacta population when they were regressed in the nonbreeding Pintag population. Singing behavior also changed seasonally in both populations.

"Our observations of seasonal brain plasticity in these tropical birds demonstrate that the vertebrate brain is extremely flexible and sensitive to diverse environmental cues that can time seasonal reproductive physiology and behavior," they wrote. While it is not yet known what environmental cues signal breeding time, Moore hypothesizes that it could be rainfall, temperature, or food availability -- or all these cues.

Human beings are contributing to global warming, which affects factors such as temperature and rainfall, and thus food availability, but does not affect the seasonal day-length changes of higher latitudes. Therefore, Moore said, global warming could change the brain functions of tropical birds and cause problems with the timing of their mating seasons. "We’re not going to change day length," he said. "We can change weather patterns. Studies show changes in the timing of breeding and migration in birds." Global warming could be the reason, he said, and, if the brain is truly sensitive to environmental cues, the changes due to global warming could have "effects we haven’t thought of before."

While Moore’s research was driven primarily by curiosity and not by conservation concerns, "you can’t save things if you don’t understand them," he said. "Every little bit of knowledge about how things works is useful." They will next try to determine which specific environmental cues are affecting tropical-bird mating processes. Moore’s research is funded through fellowships and grants from the Society for Neuroscience and the National Science Foundation.

Sally Harris | EurekAlert!
Further information:
http://www.vt.edu
http://www.jneurosci.org/

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

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

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>