Featured Research

from universities, journals, and other organizations

Parasite arms race spurs color change in bird eggs

Date:
April 16, 2012
Source:
University of Chicago Press Journals
Summary:
The eggs laid by two African bird species have evolved different color patterns over a period of just 40 years, according to new research. The quick change appears to be driven by an unwanted guest in the nest.

Prinia bird.
Credit: Dubults / Fotolia

The eggs laid by two African bird species have evolved different color patterns over a period of just 40 years, according to new research published in The American Naturalist. The quick change appears to be driven by an unwanted guest in the nest.

Related Articles


Cuckoo finches are brood parasites. They lay their eggs in the nests of other bird species, hoping to trick someone else into raising their young. To help keep their imposter eggs from being evicted, the cuckoo eggs have evolved to look a lot like those of its most common target, the tawny-flanked prinia. But prinias have evolved a defense. Their eggs have complex patterns of spots and squiggles and can vary substantially in color from female to female. The variable colors and patterns mean the cuckoo eggs aren't always a good match, and prinias can often spot them and toss them out of the nest.

University of Cambridge researchers Claire Spottiswoode and Martin Stevens show that the cuckoo's mimicry -- and the prinia's defenses against it -- have caused the appearance of both species' eggs to change over time.

In the course of their research in Zambia, Spottiswoode and Stevens noticed that cuckoo and prinia eggs they were seeing in the wild differed markedly from those in a museum collection made at their study site. "For example, 30 years ago, cuckoo finches predominantly laid eggs that look red to our eyes, but now lay mainly blue ones," Stevens said. "Prinias in turn now more commonly lay olive-colored eggs, perhaps to escape their pursuing parasite."

To test these observations, the researchers used computer models that quantified changes on spot pattern and color in past and present eggs. Their models were calibrated to view the eggs through a bird's eyes, which are better than ours at seeing colors and distinguishing ultraviolet light.

The models confirmed the observation. The eggs are changing colors, and fast. The changes detected in this study happened over the course of just 40 years, a period "that is a mere blink of an evolutionary eye," Stevens said.

The research offers a prime example of an evolutionary arms race between parasite and host, the researchers say. The dominant color pattern of prinia eggs serves as a good defense only until the cuckoos catch up. At that point, natural selection should begin favor prinias that lay eggs with new colors, which make the cuckoo eggs stand out. In effect, the two species appear to be locked in a perpetual race around the color specrum.

"Just as humans need to invent new drugs to defeat evolving bacteria and viruses, so host defenses undergo rapid changes to evade cuckoos," Spottiswoode said.


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. Claire N. Spottiswoode, Martin Stevens. Host-Parasite Arms Races and Rapid Changes in Bird Egg Appearance. The American Naturalist, 2012; 179 (5): 633 DOI: 10.1086/665031

Cite This Page:

University of Chicago Press Journals. "Parasite arms race spurs color change in bird eggs." ScienceDaily. ScienceDaily, 16 April 2012. <www.sciencedaily.com/releases/2012/04/120416113107.htm>.
University of Chicago Press Journals. (2012, April 16). Parasite arms race spurs color change in bird eggs. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2012/04/120416113107.htm
University of Chicago Press Journals. "Parasite arms race spurs color change in bird eggs." ScienceDaily. www.sciencedaily.com/releases/2012/04/120416113107.htm (accessed October 25, 2014).

Share This



More Plants & Animals News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. 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:

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