Featured Research

from universities, journals, and other organizations

Larger Horns A Gamble For Young Soay Sheep

Date:
May 20, 2008
Source:
Cell Press
Summary:
When it comes to winning mates, larger horns are an asset for male Soay sheep. But those that grow them may be putting their young lives on the line.

When it comes to winning mates, larger horns are an asset for male Soay sheep. But those that grow them may be putting their young lives on the line.
Credit: iStockphoto/Alan Crawford

When it comes to winning mates, larger horns are an asset for male Soay sheep. But those that grow them may be putting their young lives on the line, according to a study published online on May 15th in Current Biology.

The new findings show that allocation of resources to horn growth can spell the sheep's premature demise if the environment takes a turn for the worse.

"We find that large horns decrease males' first-year survival when environmental conditions are poor," said lead author Matthew Robinson of the University of Edinburgh. "Therefore, in an unpredictable environment, high allocation to early horn growth is a gamble, the pay-offs of which depend on the environmental conditions an individual encounters during its first year of life."

The researchers did not find any evidence that horn growth in later years decreases the animals' chances at survival, "so provided males survive their first winter, large horns will only serve to increase their mating success later in life as they are better able to compete with other males," Robinson added.

Previous studies showed that when environmental conditions worsen, male sheep are more likely to die than females. The researchers had also found evidence of a tradeoff between horn growth and lifespan in normal-horned Soay males.

To explore those links further in the new study, the researchers examined the relationships between horn length and fecundity, lifespan, and lifetime reproductive success (the total number of offspring sired by a male). Because they knew how the sheep were related to one another, they were also able to separate genetic and environmental influences on those fitness traits.

They found that horn growth was selected for under good environmental conditions but was selected against under poor environmental conditions. The results reveal that in unpredictable environments no single strategy may be optimal.

Such fluctuating selection is an "intuitively appealing" explanation for the maintenance of genetic diversity in secondary sexual traits, Robinson said. Although examples of fluctuating selection have been shown before, the new findings represent the only example, as far as the researchers know, of fluctuating selection on a secondary sexual trait in the wild.

The researchers include Matthew R. Robinson, University of Edinburgh, Edinburgh, UK, Macaulay Institute, Aberdeen, UK; Jill G. Pilkington, University of Edinburgh, Edinburgh, UK; Tim H. Clutton-Brock, University of Cambridge, Cambridge, UK; Josephine M. Pemberton, University of Edinburgh, Edinburgh, UK; and Loeske. E.B. Kruuk, University of Edinburgh, Edinburgh, UK.


Story Source:

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


Cite This Page:

Cell Press. "Larger Horns A Gamble For Young Soay Sheep." ScienceDaily. ScienceDaily, 20 May 2008. <www.sciencedaily.com/releases/2008/05/080515120810.htm>.
Cell Press. (2008, May 20). Larger Horns A Gamble For Young Soay Sheep. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2008/05/080515120810.htm
Cell Press. "Larger Horns A Gamble For Young Soay Sheep." ScienceDaily. www.sciencedaily.com/releases/2008/05/080515120810.htm (accessed July 30, 2014).

Share This




More Plants & Animals News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Otters Enjoy Water Slides at Japan Zoo

Raw: Otters Enjoy Water Slides at Japan Zoo

AP (July 30, 2014) River otters were hitting the water slides to beat the summer heatwave on Wednesday at Ichikawa City's Zoological and Botanical Garden. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Rodents Rampant in Gardens Around Louvre

Rodents Rampant in Gardens Around Louvre

AP (July 29, 2014) Food scraps and other items left on the grounds by picnickers brings unwelcome visitors to the grounds of the world famous and popular Louvre Museum in Paris. (July 29) Video provided by AP
Powered by NewsLook.com
Jane Goodall Warns Great Apes Face Extinction

Jane Goodall Warns Great Apes Face Extinction

AFP (July 29, 2014) The world's great apes face extinction within decades, renowned chimpanzee expert Jane Goodall warned Tuesday in a call to arms to ensure man's closest relatives are not wiped out. Duration: 00:58 Video provided by AFP
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