TEMPE, Ariz. Mom may have been right all along, especially when we were hormone-raging teenagers, eat your veggies and good things will happen.

In a new physiological study of birds, a researcher at Arizona State University has found that carotenoids, the pigments that color carrots orange and corn yellow, have even deeper health benefits than originally thought. They appear to fight off the negative impacts that testosterone can have on an animals health.

The researchers, Kevin McGraw an assistant professor in ASUs School of Life Sciences and Daniel Ardia, of Franklin and Marshall College in Pennsylvania, focused their work on zebra finches, a common domesticated pet bird originally from Australia. Carotenoids are known to play several key roles in birds and fish, including contributing to their bright colors, which acts as a signal to attract potential mates. They also act as an antioxidant in the body, which improves immune system function.

Researchers in animal behavior often study what keeps sexual signals like bright colors or elaborate songs honest, or why all individuals cannot produce them ad nausea and try to get mates, said McGraw. The reason typically is that long tails and fancy dances incur costs. Testosterone, for example, has been thought of as a double-edged sword as it relates to sexual signals, because it enhances trait production but comes at a health price to the animal.

This study shows that testosterone may not be as costly as previously thought, so long as animals can nutritionally offset the immune detriments of testosterone. They may even experience a net health benefit as a result, explained McGraw, who studies the functions of naturally occurring chemicals in birds and their relationship to the birds colors and health.

In the case of the zebra finch, the cost is in the pigments having enough of them to develop a red beak and enough to combat testosterone, which you also need to be
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Contact: Skip Derra
skip.derra@asu.edu
480-965-4823
Arizona State University
11-Jun-2007