Featured Research

from universities, journals, and other organizations

Elaborate bird plumage due to testosterone?

Date:
October 31, 2011
Source:
Max-Planck-Gesellschaft
Summary:
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. Researchers have now investigated whether this also holds true for sex role-reversed bird species.

Female barred buttonquails: their testosterone levels determine the size and colour intensity of their black throat patch.
Credit: Cornelia Voigt, MPI f. Ornithology

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.

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.


Story Source:

The above story is based on materials provided by Max-Planck-Gesellschaft. Note: Materials may be edited for content and length.


Journal Reference:

  1. Christina Muck, Wolfgang Goymann. Throat patch size and darkness co-varies with testosterone in females of a sex-role reversed species. Behavioral Ecology, 2011; (in press)

Cite This Page:

Max-Planck-Gesellschaft. "Elaborate bird plumage due to testosterone?." ScienceDaily. ScienceDaily, 31 October 2011. <www.sciencedaily.com/releases/2011/10/111021074732.htm>.
Max-Planck-Gesellschaft. (2011, October 31). Elaborate bird plumage due to testosterone?. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2011/10/111021074732.htm
Max-Planck-Gesellschaft. "Elaborate bird plumage due to testosterone?." ScienceDaily. www.sciencedaily.com/releases/2011/10/111021074732.htm (accessed October 23, 2014).

Share This



More Plants & Animals News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Working Mother DIY: Pumpkin Pom-Pom

Working Mother DIY: Pumpkin Pom-Pom

Working Mother (Oct. 22, 2014) How to make a pumpkin pom-pom. Video provided by Working Mother
Powered by NewsLook.com
Goofy Dinosaur Blends Barney and Jar Jar Binks

Goofy Dinosaur Blends Barney and Jar Jar Binks

AP (Oct. 22, 2014) A collection of dinosaur bones reveal a creature that is far more weird and goofy-looking than scientists originally thought when they found just the arm bones nearly 50 years ago, according to a new report in the journal Nature. (Oct. 22) Video provided by AP
Powered by NewsLook.com
San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

San Diego Zoo's White Rhinos Provide Hope for the Critically Endangered Species

Reuters - Light News Video Online (Oct. 22, 2014) The pair of rare white northern rhinos bring hope for their species as only six remain in the world. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
Raw: Bear Cub Strolls Through Oregon Drug Store

Raw: Bear Cub Strolls Through Oregon Drug Store

AP (Oct. 22, 2014) Shoppers at an Oregon drug store were surprised by a bear cub scurrying down the aisles this past weekend. (Oct. 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins