Feather color is more than skin deep

Apr 15, 2009

Where do birds get their red feathers from? According to Esther del Val, from the National History Museum in Barcelona, Spain, and her team, the red carotenoids that give the common crossbill (Loxia curvirostra) its red coloration are produced in the liver, not the skin, as previously thought. Their findings, published online in Springer's journal Naturwissenschaften, have implications for understanding the evolution of color signaling in bird species.

Carotenoids have important physiological functions, including antioxidant, immunomodulating, and photoprotectant properties. Carotenoid pigments are also used by many bird species as colorants, and are responsible for most of their red, orange and yellow coloration. In particular, carotenoid-red coloration in has been shown to act as an ornament, signaling the nutritional and health status of the individual and its ability to locate high quality resources. Recent studies have suggested that the transformation of carotenoid pigments takes place directly in the follicles during feather growth.

Del Val and her team show for the first time that, contrary to previous assumptions, the liver acts as the main site for the synthesis of carotenoids responsible for the birds' coloration, not the skin.

The researchers examined the carotenoid content of the liver, blood, skin and feathers of seven common crossbills (finches) in which adult males display carotenoid-based coloration on the throat, breast and rump. They were particularly interested in the anatomical origin of the birds' red plumage. They found the primary red feather of male crossbills in the birds' liver and blood, implying that the carotenoids are synthesized in the liver and then travel to the peripheral tissues via the .

Del Val concludes: "This surprising divergence with previous studies raises the question whether there are inter-specific differences in anatomical sites for conversion of carotenoids. Understanding inter-specific variation in mechanisms of color production may be the key to comprehend the different evolutionary pathways involved in color signaling."

More information: Del Val E et al (2009). The liver but not the skin is the site for conversion of a red carotenoid in a passerine bird. Naturwissenschaften. DOI 10.1007/s00114-009-0534-9

Source: Springer

Explore further: Mitochondrial metagenomics: How '-omics' is saving wild bees

Related Stories

Radical Scavengers in Red Smear Cheeses

Dec 15, 2008

(PhysOrg.com) -- Carotenoids not only give carrots and red smear cheeses, such as Munster, Limburger, and Romadur, their characteristic red color, but they also protect organisms from oxidative stress. A research team headed ...

Fossil feathers preserve evidence of color

Jul 09, 2008

The traces of organic material found in fossil feathers are remnants of pigments that once gave birds their color, according to Yale scientists whose paper in Biology Letters opens up the potential to dep ...

Brightly colored birds most affected by Chernobyl radiation

Jul 11, 2007

Brightly coloured birds are among the species most adversely affected by the high levels of radiation around the Chernobyl nuclear plant, ecologists have discovered. The findings – published online in the British Ecological ...

Recommended for you

Mitochondrial metagenomics: How '-omics' is saving wild bees

1 hour ago

Mitochondrial genome (mitogenome) database demonstrated its great value on detecting wild bees in UK farms via mitochondrial metagenomics pipeline, a new approach developed by scientists from the China National Genebank (CNGB), ...

Study shows grey squirrels are quick learners

23 hours ago

They may be viewed by some as an invasive species or a commonplace pest of public parks, but a new study from the University of Exeter has shown that grey squirrels are actually quick learners capable of ...

Age and fertility in social insects

Jul 06, 2015

A new research unit coordinated at the University of Freiburg tackles the question of why the otherwise usual trade-off between fecundity and lifespan in multicellular organisms is not present in social insects ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.