PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Elaborate plumage due to testosterone?

In female barred buttonquails high testosterone levels correlate with elaborate plumage and good body condition

Elaborate plumage due to testosterone?
2011-10-22
(Press-News.org) In many bird species males have a more elaborate plumage than females. This elaborate plumage is often used to signal body condition, to intimidate rivals or to attract potential mates. In many cases plumage colouration also depends on the hormone testosterone. Christina Muck and Wolfgang Goymann from the Max Planck Institute for Ornithology in Seewiesen have now investigated whether this also holds true for sex role reversed bird species. In barred buttonquails that live in Southeast Asia, females are polygamous and pair with several males that incubate the eggs and raise the young. However, not only the behaviour, but also secondary sexual ornaments that depend on the male hormone testosterone are reversed between sexes.

Women who use typical male strategies to promote their careers are often not successful. Recent findings suggest that this strategy often leads to the opposite effect. Apparently certain behaviours are considered to be typical male, such as being offensive in business matters. Also in birds one can find clearly defined roles: The male defends a territory, courts a female and on top of has the better looks due to his elaborate plumage.

Colourful plumage and long feathers allow a male to express its quality and/or condition without further physical demonstration of its strength. With such features they may be able to avoid physical fights which are costly with respect to energy expenditure and the risk of injuries. The size and intensity of some parts of the plumage, for example the so-called black bib in house sparrows, depends on the male sex hormone testosterone; males with high testosterone levels also possess a larger and more intensely coloured bib.

There is hardly anything known regarding function and regulation of plumage colouration in female birds: females mostly have a dull plumage with almost no variation between individuals. However, in a few bird species sex roles are reversed: here, the females aggressively defend territories and court males. The latter incubate the eggs and care for the young without any help from the females. Only very few species are known to show such sex role reversal in behaviour and the evolutionary background is still unsolved.

Christina Muck and Wolfgang Goymann now found a relationship between plumage colouration, body weight and testosterone concentrations in female barred buttonquail, a bird species that lives in Southeast Asia. The researchers kept the birds in pairs for one year in large breeding boxes and regularly took blood samples to monitor the time course of testosterone levels. In addition they weighed the birds and took photographs of the black throat patch of females to determine its size and colour intensity on the computer. Males of this species are smaller than females and do not possess such a patch.

The researchers could first show that testosterone levels were similar in males and females and did not exhibit large seasonal changes. Moreover, testosterone levels were rather low which is common is species that do not show a pronounced seasonality. Nevertheless they found a strong relationship between the size and the intensity of the black throat patch and the testosterone levels in females. Moreover, in females there was a correlation between testosterone levels and female body condition. No such correlations existed in males.

"It is really remarkable", states Christina Muck, "that the sex role reversal in behaviours is accompanied by a reversed hormone dependency in the expression of secondary sexual characters". Thus, female button quails succeed when they not only adopt male behavioural strategies but also use the underlying physiological mechanisms.



INFORMATION:

Original paper:

Christina Muck, Wolfgang Goymann
Throat patch size and darkness co-varies with testosterone in females of a sex-role reversed species

Behavioural Ecology, in press


[Attachments] See images for this press release:
Elaborate plumage due to testosterone?

ELSE PRESS RELEASES FROM THIS DATE:

How Long do LASIK Results Last?

2011-10-22
LASIK vision correction is a long-term solution. The eye surgery changes the shape of your cornea, permanently altering the way that your eye receives light. The longevity of your LASIK results depends greatly on whether you will undergo age-related vision changes and if you had a stable prescription prior to surgery. During an initial LASIK consultation, your LASIK doctor will make sure you are a good candidate for the eye surgery. Vision after LASIK LASIK eye surgery changes the shape of your cornea, allowing your eye to correctly focus light for clear and precise ...

More African-Americans burdened by osteoarthritis in multiple large joints

2011-10-22
New research suggests African Americans have a higher burden of multiple, large-joint osteoarthritis (OA), and may not be recognized based on the current definition of "generalized OA." African Americans were also more likely to have knee OA, but less likely to be affected by hand OA than Caucasians according to the findings reported today in Arthritis & Rheumatism, a peer-reviewed journal of the American College of Rheumatology (ACR). OA is the most common type of arthritis and typically affects multiple joints. The National Institute of Arthritis and Musculoskeletal ...

Social Security Benefits for Those with Depression

2011-10-22
Clinical depression is a serious problem in the United States. According to estimates by the Washington University in Saint Louis School of Medicine, approximately 9.2 million Americans suffer from severe or clinical depression. By 2020, the World Health Organization (WHO) estimates that clinical depression will be the number two cause of "lost years of healthy life" worldwide. Fortunately, those who suffer from severe, debilitating depression can qualify for Social Security Disability (SSD) benefits. What Is Depression? Depression is much more than simply ...

European studies on risks of hepatocellular carcinoma

2011-10-22
Among known risk factors for hepatocellular cancer, smoking, obesity, and heavy alcohol consumption, along with chronic hepatitis B and C infection, contribute to a large share of the disease burden in Europe, according to a cohort study published online October 21 in the Journal of the National Cancer Institute. While a causal link between hepatitis B and C and hepatocellular cancer has been known for a few decades, tobacco smoking, obesity, and alcohol consumption are common risk factors, albeit with lower relative risks, that also contribute to the development of ...

Pastoralists in drought-stricken Kenya receive insurance payouts for massive livestock losses

2011-10-22
MARSABIT, KENYA (21 October 2011) – In the midst of a drought-induced food crisis affecting millions in the Horn of Africa, an innovative insurance program for poor livestock keepers is making its first payouts today, providing compensation for some 650 insured herders in northern Kenya's vast Marsabit District who have lost up to a third of their animals. Known as Index Based Livestock Insurance or IBLI, payouts are triggered when satellite images show that grazing lands in the region have deteriorated to the point that herders are expected to be losing more than 15 ...

New discoveries on the state of hemoglobin in living red blood cells

New discoveries on the state of hemoglobin in living red blood cells
2011-10-22
Professor Qin Wenbin from BaoTou Medical College first identified the hemoglobin (Hb) A2 phenomenon 30 years ago. His first paper on this phenomenon was published in Acta Biochimica et Biophysica Sinica, in Chinese, in 1981. Subsequent research investigating its mechanism was published in Chinese in the Chinese Biochemical Journal and Progress in Biochemistry and Biophysics in 1991 and more recently in Electrophoresis, in 2010. Using electrophoretic methods, he discovered that Hb is re-released in living red blood cells (RBCs) and demonstrated the significance of this process ...

New Study: Anesthesia Death Rate Rising, Older Patients at Risk

2011-10-22
After decades of decline, the worldwide death rate from full anesthesia is quietly creeping higher. According to an article recently published in the German Medical Association's official international science journal, the death rate during full anesthesia has reached approximately seven patients per million. In contrast, deaths from full anesthesia only affected four patients per million at the end of the 1980s. This disturbing trend may serve as a wakeup call to alert doctors that special precautions are warranted when anesthetizing at risk patients. Reasons Anesthesia ...

New instrument helps researchers see how diseases start and develop in minute detail

2011-10-22
Magnetic resonance imaging (MRI) is an established technique which over the years has made it possible for researchers and healthcare professionals to study biological phenomena in the body without using ionising radiation, for example X-rays. The images produced by normal MRI are, to put it simply, pictures of water in the body, since the body is largely made up of water. MRI produces images of the hydrogen nuclei in water molecules. It can also be used to study other types of nuclei in many other interesting molecules. The only problem is that the concentration of ...

No simultaneous warming of Northern and Southern hemispheres as a result of climate change for 20,000 years

2011-10-22
However, Svante Björck, a climate researcher at Lund University in Sweden, has now shown that global warming, i.e. simultaneous warming events in the northern and southern hemispheres, have not occurred in the past 20 000 years, which is as far back as it is possible to analyse with sufficient precision to compare with modern developments. Svante Björck's study thus goes 14 000 years further back in time than previous studies have done. "What is happening today is unique from a historical geological perspective", he says. Svante Björck has gone through the global ...

Digital worlds can help autistic children to develop social skills

2011-10-22
The benefits of virtual worlds can be used to help autistic children develop social skills beyond their anticipated levels, suggest early findings from new research funded by the Economic and Social Research Council (ESRC). Researchers on the Echoes Project have developed an interactive environment which uses multi-touch screen technology where virtual characters on the screener act to children's actions in real time. During sessions in the virtual environment, primary school children experiment with different social scenarios, allowing the researchers to compare their ...

LAST 30 PRESS RELEASES:

NASA scientists find new human-caused shifts in global water cycle

This tiny galaxy is answering some big questions

Large and small galaxies may grow in ways more similar than expected

The ins and outs of quinone carbon capture

Laboratory for Laser Energetics at the University of Rochester launches IFE-STAR ecosystem and workforce development initiatives

Most advanced artificial touch for brain-controlled bionic hand

Compounding drought and climate effects disrupt soil water dynamics in grasslands

Multiyear “megadroughts” becoming longer and more severe under climate change

Australopithecines at South African cave site were not eating substantial amounts of meat

An AI model developed to design proteins simulates 500 million years of protein evolution in developing new fluorescent protein

Fine-tuned brain-computer interface makes prosthetic limbs feel more real

New chainmail-like material could be the future of armor

The megadroughts are upon us

Eavesdropping on organs: Immune system controls blood sugar levels

Quantum engineers ‘squeeze’ laser frequency combs to make more sensitive gas sensors

New study reveals how climate change may alter hydrology of grassland ecosystems

Polymer research shows potential replacement for common superglues with a reusable and biodegradable alternative 

Research team receives $1.5 million to study neurological disorders linked to long COVID

Research using non-toxic bacteria to fight high-mortality cancers prepares for clinical trials

Do parents really have a favorite child? Here’s what new research says

Mussel bed surveyed before World War II still thriving

ACS Annual Report: Cancer mortality continues to drop despite rising incidence in women; rates of new diagnoses under 65 higher in women than men

Fewer skin ulcers in Werner syndrome patients treated with pioglitazone

Study finds surprising way that genetic mutation causes Huntington’s disease, transforming understanding of the disorder

DNA motors found to switch gears

Human ancestor thrived longer in harsher conditions than previous estimates

Evolution: Early humans adapted to extreme desert conditions over one million years ago

Race and ethnicity and diffusion of telemedicine in Medicaid for schizophrenia care after onset of the COVID-19 pandemic

Changes in support for advance provision and over-the-counter access to medication abortion

Protein level predicts immunotherapy response in bowel cancer

[Press-News.org] Elaborate plumage due to testosterone?
In female barred buttonquails high testosterone levels correlate with elaborate plumage and good body condition