Meeting Abstract

P2.50  Jan. 5  Variability in carotenoid accumulation among molting house finches WASHINGTON, L.L.*; MCGRAW, K.J.; Arizona State University Lauren.Washington@asu.edu

Many animals use diet-derived carotenoid pigments to become colorful and sexually attractive. Individuals that acquire the most carotenoids from food are thought to be the most colorful. However, many different carotenoids have been described, with some that may be more valuable for coloration than others. Few studies have analyzed carotenoids in relation to important demographic parameters (e.g. age, sex, season). We sampled blood from wild-caught, molting house finches on the ASU campus and determined carotenoid levels using HPLC. Male finches display carotenoid-containing plumage that varies from red to yellow; females prefer to mate with the reddest males. We detected a series of 6 carotenoids (lutein, zeaxanthin, dehydrolutein, &beta-cryptoxanthin, rubixanthin, and &beta-carotene), with two dietary xanthophylls (lutein and zeaxanthin) being predominant (75% of total). Xanthophyll concentrations in blood were low early in molt and high in the middle of molt. Males had higher carotenoid concentrations than females; this difference was driven solely by levels of &beta-cryptoxanthin (a precursor for red plumage pigments). Finally, young males had higher concentrations than adults, though this difference was due only to lutein. Ultimately, age and seasonal differences in carotenoid levels do not appear to be linked to development of optimal coloration, because lutein is driving these significant changes but produces yellow plumage color. Since males are redder and have higher &beta-cryptoxanthin levels than females, our data supports the strategy of acquiring as much &beta-cryptoxanthin as possible for bright pigmentation.