Post by oldmike on Sept 30, 2006 17:10:41 GMT 7
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Evolution holds hope for ugly males. Females appear to invest extra energy in getting their poorer-quality offspring off to a good start, at least among house finches (Carpodacus mexicanus).
Female birds can deposit different amounts of health-promoting compounds in their eggs, depending on social and environmental conditions. Previous studies on zebra finches showed that females were more likely to invest in eggs fertilised by high-quality males.
Kristen Navara, now at Ohio State University in Columbus, expected to see the same pattern with house finches, in which red feathers are the hallmark of health. However, her measurements showed the opposite. Eggs from matings with less-attractive males, that is, those with drab plumage, contained 2.5 times more yolk antioxidants, including vitamin E and three carotenoids, which colour the plumage red. The study will appear in a future issue of Physiological and Biochemical Zoology.
That shows the house finches have a different strategy, Navara says. Their lifespan extends over only 1 or 2 mating seasons, so it makes sense for them to add health promoters to eggs fertilised by low-quality, "ugly" fathers in an attempt to compensate for their inadequacies. "They're trying to make the most of the reproductive event," she says.
Evolution holds hope for ugly males. Females appear to invest extra energy in getting their poorer-quality offspring off to a good start, at least among house finches (Carpodacus mexicanus).
Female birds can deposit different amounts of health-promoting compounds in their eggs, depending on social and environmental conditions. Previous studies on zebra finches showed that females were more likely to invest in eggs fertilised by high-quality males.
Kristen Navara, now at Ohio State University in Columbus, expected to see the same pattern with house finches, in which red feathers are the hallmark of health. However, her measurements showed the opposite. Eggs from matings with less-attractive males, that is, those with drab plumage, contained 2.5 times more yolk antioxidants, including vitamin E and three carotenoids, which colour the plumage red. The study will appear in a future issue of Physiological and Biochemical Zoology.
That shows the house finches have a different strategy, Navara says. Their lifespan extends over only 1 or 2 mating seasons, so it makes sense for them to add health promoters to eggs fertilised by low-quality, "ugly" fathers in an attempt to compensate for their inadequacies. "They're trying to make the most of the reproductive event," she says.