Why do birds have red hair? According to Esther del Val, of the Barcelona, Spain Natural History Museum, and colleagues, the red pigment gives the cross-sparrow finch (Loxia curvirostra) the red coat, created in the liver, not skin like previous thoughts.
The new study shows that red pigments give crossbills sparrow red feathers created in the liver, not the skin as previously thought.
Their findings, published online in Springer's whole journal Naturwissenschaften, are important in understanding the evolution of color signals in birds.
Pigments have important physiological functions, including antioxidant, immune modulation, and optical protection properties. Pigments are also used by many birds as dyes, and are responsible for red, orange and yellow. Specifically, the red pigment in birds acts as a signal to show the health and nutrition status of an individual and its ability to find good food sources. Recent studies show that pigment changes take place directly in cocoons when hair grows.
Del Val and his team showed for the first time that, contrary to previous predictions, the liver is where pigmentation is responsible for the color of the hair, not the skin. The researchers examined the composition of pigments in the liver, blood, skin and hair of seven cross-sparrow finches, birds whose males have red breast hair, tail and neck. They are particularly interested in the anatomical origin of the red feathers of birds.They found that the male red-billed finch red pigments are located in the liver and blood, meaning that the pigment is synthesized in the liver and then transported to external tissues through the blood stream.
Del Val concluded : 'This surprising disagreement with previous studies raises the question of whether there are inter-species anatomical differences in pigmentation changes. Understanding the transformation of color formation mechanism among species may be the key to complete different evolutionary processes including color signals'.
Refer:
Val et al.Lỗi nhưng mà không phải là skins là việc để chuyển đổi của một Red carotenoid trong một passerine bird.Naturwissenschaften, 2009;DOI: 10.1007 / s00114-009-0534-9