Featured Research

from universities, journals, and other organizations

Costs and benefits of testosterone in birds

Date:
May 20, 2010
Source:
University of Chicago Press Journals
Summary:
Do nice guys finish last, or will the meek inherit the earth? A new study suggests that, at least for birds, the right answer is somewhere in between.

Do nice guys finish last, or will the meek inherit the earth? A new study published in The American Naturalist suggests that, at least for birds, the right answer is somewhere in between.

Individual male birds can differ dramatically in their behavior, and this difference is often due in part to how much testosterone they produce. In many species, some males produce high testosterone and are more aggressive, while others produce lower levels and are more parental.

Testosterone and the behaviors it mediates may predict how well a male succeeds. For example, an aggressive male may be more likely to obtain high-quality territories that attract females. At the same time, aggression might pose a survival risk, because aggressive males might be more likely to engage in costly fights. These considerations suggest that hormones like testosterone might be under strong natural selection in the wild.

To test this idea, a team of researchers from Indiana University studied a common songbird, the dark-eyed junco in the Appalachian Mountains of Virginia. They tested how much testosterone a male could produce by using an injection of a hormone produced in the brain that causes the bird to increase its testosterone levels temporarily, mimicking what they do naturally when fighting with other males. The researchers then followed the birds, measuring their survival and success at reproduction, both in their own nest and those of their neighbors.

They found strong relationships between testosterone and both reproduction and survival, demonstrating that natural selection is currently acting on testosterone production in this population of juncos. The exact pattern of selection they found was surprising, however. "The males that did the best at both survival and reproduction had testosterone production very close to average," said Joel McGlothlin, the lead author of the study who is now a postdoctoral fellow at the University of Virginia. "It was bad to produce either really high or really low levels of testosterone." High-testosterone males did have one universal advantage -- they were more likely to be the genetic father of the offspring raised in their nests.

These results indicate that the trade-offs that testosterone regulates are quite complex. "It's not as simple as saying testosterone is good for reproduction and bad for survival," McGlothlin said. "Testosterone seems to underlie this delicate balance between competing traits and behaviors, and the right balance might be different for different males."


Story Source:

The above story is based on materials provided by University of Chicago Press Journals. Note: Materials may be edited for content and length.


Journal Reference:

  1. JoelW. McGlothlin, DanielleJ. Whittaker, SaraE. Schrock, NicoleM. Gerlach, JodieM. Jawor, EricA. Snajdr, EllenD. Ketterson. Natural Selection on Testosterone Production in a Wild Songbird Population. The American Naturalist, 2010; 175 (6): 687 DOI: 10.1086/652469

Cite This Page:

University of Chicago Press Journals. "Costs and benefits of testosterone in birds." ScienceDaily. ScienceDaily, 20 May 2010. <www.sciencedaily.com/releases/2010/05/100513112753.htm>.
University of Chicago Press Journals. (2010, May 20). Costs and benefits of testosterone in birds. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2010/05/100513112753.htm
University of Chicago Press Journals. "Costs and benefits of testosterone in birds." ScienceDaily. www.sciencedaily.com/releases/2010/05/100513112753.htm (accessed April 19, 2014).

Share This



More Plants & Animals News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Vermont Goat Meat Gives Refugees Taste of Home

Vermont Goat Meat Gives Refugees Taste of Home

AP (Apr. 18, 2014) Dairy farmers and ethnic groups in Vermont are both benefiting from a unique collaborative effort that's feeding a growing need for fresh and affordable goat meat. (April 18) Video provided by AP
Powered by NewsLook.com
First Ever 'Female Penis' Discovered In Animal Kingdom

First Ever 'Female Penis' Discovered In Animal Kingdom

Newsy (Apr. 18, 2014) Not only are these newly discovered bugs' sex organs reversed, but they also mate for up to 70 hours. Video provided by Newsy
Powered by NewsLook.com
Little Progress Made In Fighting Food Poisoning, CDC Says

Little Progress Made In Fighting Food Poisoning, CDC Says

Newsy (Apr. 18, 2014) A new report shows rates of two foodborne infections increased in the U.S. in recent years, while salmonella actually dropped 9 percent. Video provided by Newsy
Powered by NewsLook.com
The Great British Farmland Boom

The Great British Farmland Boom

Reuters - Business Video Online (Apr. 17, 2014) Britain's troubled Co-operative Group is preparing to cash in on nearly 18,000 acres of farmland in one of the biggest UK land sales in decades. As Ivor Bennett reports, the market timing couldn't be better, with farmland prices soaring over 270 percent in the last 10 years. Video provided by Reuters
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:
from the past week

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