Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research: removal of dominant rivals causes male cichlid fish to undergo remarkable transformation

19.10.2005


In a new study of cichlid fish descended from others caught in East Africa’s Lake Tanganika, scientists have made some surprising observations about how those animals respond to changes in their environments known as "social opportunities."



Dr. Sabrina S. Burmeister, assistant professor of biology at the University of North Carolina at Chapel Hill’s College of Arts and Sciences, and colleagues found that subordinate male fish underwent a radical and rapid transformation when more dominant males were removed.

"When we took dominant cichlid males from an experimental tank, subordinate males started becoming dominant themselves in as few as two minutes," Burmeister said. "Their colors -- blue and yellow -- got much brighter, a black stripe we call an eye bar appeared near their eyes, and they became much more aggressive than they were before. The remaining males also quickly paid a lot more attention to females because for the first time, they had an opportunity to reproduce."


No one had any idea before that perceived changes in their social status could begin altering animals’ behavior and appearance so quickly, she said. Previous studies had shown the changes took as long as a week and were associated with increased fertility.

Burmeister’s report on her experiments, conducted at Stanford University, appears in the November issue of the scientific journal PloS Biology, which is being released today (Oct. 17). Co-authors are Drs. Erich D. Jarvis and Russell D. Fernald, neurobiologists at Duke University and Stanford, respectively.

The research is part of a larger effort to understand some of the most intriguing questions in all of biology -- how did brains evolve and how can the environment change an animal’s physiology through actions on its brain?

Such studies are relevant to humans since the hormones and genes involved are close to identical, she said. Obviously, such internal gene activity studies cannot be done directly in humans.

After observing the striking changes in appearance and personality, Burmeister and colleagues turned their attention to the inner workings of the fish’s gene-hormone interactions by analyzing brain tissue.

"The gene we focused on, egr-1, was a good candidate for study because it controls expression of other genes," Burmeister said. "We found that perception of social opportunity caused more egr-1 to be expressed in the hypothalamus, a region of the brain that controls fertility. We believe that in our fish, egr-1 turns on expression of a second gene, GnRH1, which produces a hormone necessary for reproduction."

The basic mechanisms that control reproduction in fish and in humans are the same and may be in all vertebrates, she said. The brain’s hypothalamus links the nervous system to hormonal systems.

"Reproductive physiology is often influenced by environmental factors, including social cues, the scientist said. "In humans, one of the best examples came from work by Dr. Martha McClintock showing that the menstrual cycles of women were influenced by olfactory cues from other women. Another group found that the timing of ovulation in women is influenced by olfactory cues from men."

In humans and many other mammals, olfactory cues -- various odors --provide important information about the social environment, Burmeister said. The situations are analogous -- social cues from the environment influence the reproductive system through GnRH neurons and create a "cascade" of molecular interactions that result in increased fertility.

The National Institutes of Health and the National Science Foundation supported the research.

David Williamson | EurekAlert!
Further information:
http://www.unc.edu

More articles from Studies and Analyses:

nachricht Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>