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 Modern genetic sequencing tools give clearer picture of how corals are related
17.08.2017 | University of Washington

nachricht The irresistible fragrance of dying vinegar flies
16.08.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Climate change: In their old age, trees still accumulate large quantities of carbon

17.08.2017 | Earth Sciences

Modern genetic sequencing tools give clearer picture of how corals are related

17.08.2017 | Life Sciences

Superconductivity research reveals potential new state of matter

17.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>