Rich-orange bills serve male puffins as extravagant displays calculated to dazzle females into believing they have the wherewithal to be handsome providers. Despite their usual sober black and white attire, these jaunty little seabirds project a comical appearance. Yet, there is nothing humorous about their marginal life in the North Pacific (or Atlantic). Out-smarting hungry predators, wresting a living from shrinking supplies of fish, and coping with the occasional oil spill take their toll. In the spring puffins take a break and head for the beach - to the precise location of their hatching. Since puffins usually mate for life and have but one puffling a year, males spare no expense in attracting just the right female. Contriving to make her swoon, male puffins bulk-up their stout little bills with arc-shaped plates and pump eye-catching bright orange pigments into their bare parts (bills, legs, and webbed feet). Are these lavish displays honest advertising? Do female puffins, like the young ladies in Jane Austin novels, have difficulty discriminating the genuine Mr. Darcy from the posturing of charlatans?
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144: 167617 A novel lipoprotein-mediated mechanism controlling sexual attractiveness in a colorful songbird. McGraw, Kevin J.; Parker, Robert S. Department of Neurobiology and Behavior, Cornell University, Ithaca, NY, USA. Physiology & Behavior 2006, 87 (1), 103-108 (Eng). Sexually selected traits like complex vocalizations or vibrant colors communicate reliable information about mate quality when they are costly to display. Although several general condition-dependent mechanisms underlying the acquisition of mating advertisements have been identified, the authors rarely know the precise physiol. and mol. challenges that animals must meet to develop their sexual ornaments. The flashy pigment-based colors commonly displayed by birds are ideal candidates for investigating the pathways and demands of sexual-signal expression, because the authors know the biochem. currency with which the trait is produced. Carotenoid colors in birds, for example, are derived from pigments that are acquired from the diet and assimilated into feathers and bare parts. In previous work, the authors showed that variation in the sexually attractive red carotenoid-colored beak of male zebra finches (Taeniopygia guttata) was predicted not by the amt. of food or pigments ingested, but by the levels of carotenoids that birds circulated in blood. Here the authors elucidate a novel physiol. mechanism by which birds are able to accumulate high levels of carotenoids in the body and develop a colorful bill. Carotenoids are transported through the bloodstream bound to lipoproteins. The authors assayed a crit. component of lipoprotein particles-cholesterol and found that males with higher cholesterol levels circulated more carotenoids and displayed redder beaks. Exptl. supplementation of dietary cholesterol elevated carotenoid levels in the blood and beak hue. Exptl. redns. in blood cholesterol, using the human lipid-lowering agent atorvastatin, diminished blood carotenoids and faded the beak; carotenoid and cholesterol levels were restored, however, by subsequent addn. of dietary cholesterol. These results suggest that the prodn. of...
139: 50042 Carotenoid Modulation of Immune Function and Sexual Attractiveness in Zebra Finches. Blount, Jonathan D.; Metcalfe, Neil B.; Birkhead, Tim R.; Surai, Peter F. Institute of Biomedical and Life Sciences, Division of Environmental and Evolutionary Biology, University of Glasgow, Glasgow, UK. Science 2003, 300(5616), 125-127 (Eng). One hypothesis for why females in many animal species frequently prefer to mate with the most elaborately ornamented males predicts that availability of carotenoid pigments is a potentially limiting factor for both ornament expression and immune function. An implicit assumption of this hypothesis is that males that can afford to produce more elaborate carotenoid-dependent displays must be healthier...
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Cholesterol
CAS Registry Number: 57-88-5
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Updated: 1/26/2009 2:20:08 PM
