Featured Research

from universities, journals, and other organizations

Testosterone regulates solo song of tropical birds

Date:
October 31, 2012
Source:
Max-Planck-Gesellschaft
Summary:
An experiment in females uncovers male hormonal mechanism.

A pair of white-browed sparrow weavers. In these African songbirds, which live in status-dependent groups, it is the dominant males that call the tune – only they sing a special, complex solo song at dawn. Females and subdominant males, by contrast, perform identical, alternating duets.
Credit: MPI for Ornithology

In male songbirds of the temperate zone, the concentration of sex hormones is rising in spring, which leads to an increase in song activity during the breeding season. In the tropics, there has been little evidence so far about such a clear relationship between hormonal action and behaviour, which is partly due to a lower degree of seasonal changes of the environment.

Researchers from the Max Planck Institute for Ornithology in Seewiesen have now discovered that in duetting African white-browed sparrow weavers, the solo song of dominant males is linked to elevated levels of testosterone. What is more, the male-typical solo song could be activated via testosterone treatment in female birds. The study thus shows a complex relationship between song behaviour and hormone concentration also in a tropical bird species.

In species of the temperate zone, circannual rhythms are triggered by seasonal fluctuations in day length. The longer days in spring are accompanied by an increase of steroid hormone levels that lead to the onset of breeding activities. Consequently, there are changes in behaviour and at least in male songbirds, there is a relationship between the incidence and complexity of songs and circulating testosterone concentrations. In the tropics, however, the situation is different. Birds often vocalise year-round, and there are suitable conditions for breeding during a more extended period compared to the temperate zone. In addition, in many species testosterone concentrations are at a low level throughout the year. The underlying mechanism responsible for the song changes of tropical birds therefore remains elusive.

Cornelia Voigt and Stefan Leitner from the Max Planck Institute for Ornithology now showed that testosterone plays a crucial role in the regulation of song behaviour in African white-browed sparrow weavers (Plocepasser mahali). These birds live in groups of two to ten individuals and are characterized by a status-dependent song, where only the dominant male sings a so-called "solo song," whereas females and subordinate males sing an alternating duet song. In a long-term study of sparrow weaver colonies in Southwestern Zimbabwe, the researchers found a relationship between hormone levels and solo song in males. Dominant males had higher testosterone values than subordinate birds, both in the early breeding season from October until December and in the late breeding season from January until March.

However, these hormone concentrations were much lower compared to those responsible for song changes in temperate zone species. It could well be that the slightly higher values of dominant males only reflect the hierarchical status itself and are not responsible for the activation of solo song. That testosterone indeed plays a role in solo singing could be proved in an experiment in females that were kept in aviaries next to their natural habitat. These females received a testosterone implant. Within a week they started to sing the male-typical solo song that was fully developed after one month and differed only in a few features from male song. "With this study, we could show that a special type of song, the solo song, can be activated by testosterone in both sexes. Moreover, females remain receptive for the male hormone testosterone," says Cornelia Voigt.


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. Cornelia Voigt, Stefan Leitner. Testosterone-dependency of male solo song in a duetting songbird — Evidence from females. Hormones and Behavior, 2012; DOI: 10.1016/j.yhbeh.2012.10.006

Cite This Page:

Max-Planck-Gesellschaft. "Testosterone regulates solo song of tropical birds." ScienceDaily. ScienceDaily, 31 October 2012. <www.sciencedaily.com/releases/2012/10/121031132750.htm>.
Max-Planck-Gesellschaft. (2012, October 31). Testosterone regulates solo song of tropical birds. ScienceDaily. Retrieved April 20, 2014 from www.sciencedaily.com/releases/2012/10/121031132750.htm
Max-Planck-Gesellschaft. "Testosterone regulates solo song of tropical birds." ScienceDaily. www.sciencedaily.com/releases/2012/10/121031132750.htm (accessed April 20, 2014).

Share This



More Plants & Animals News

Sunday, April 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Mich. Boy Unearths 10,000-Year-Old Mastodon Tooth

Mich. Boy Unearths 10,000-Year-Old Mastodon Tooth

Newsy (Apr. 20, 2014) A 9-year-old Michigan boy was exploring a creek when he came across a 10,000-year-old tooth from a prehistoric mastodon. Video provided by Newsy
Powered by NewsLook.com
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
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. Video provided by Newsy
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

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