TY - JOUR
T1 - Are yolk androgens and carotenoids in barn swallow eggs related to parental quality?
AU - Safran, Rebecca J.
AU - Pilz, Kevin M.
AU - McGraw, Kevin J.
AU - Correa, Stephanie M.
AU - Schwabl, Hubert
N1 - Funding Information:
Acknowledgments John Anderson and Maura Byrne were invaluable during the field portion of this study. Funding for this study was obtained by the Cornell University chapter of Sigma Xi and the American Museum of Natural History. R.J. Safran was supported by an American Association of University Women Fellowship during data collection and a Princeton University Council on Science and Technology Fellowship during manuscript preparation; K.M. Pilz was supported by a Howard Hughes Medical Institute Predoctoral Fellowship, K.J. McGraw was supported by an EPA STAR Fellowship, and S. Correa was supported by a SUNY Minority Fellowship during the data collection phase of this project. We acknowledge the insightful comments of the Hau and Wikelski Labs at Princeton University, Ian Hartley, and two anonymous reviewers whose suggestions greatly improved our manuscript. Permission to collect eggs was granted by the US Fish and Wildlife Service and the New York Department of Environmental Conservation.
PY - 2008/1
Y1 - 2008/1
N2 - Recently, evidence is mounting that females can adaptively engineer the quality of their offspring via the deposition of yolk compounds, including carotenoids and androgens. In this study, we simultaneously consider how both carotenoids and androgens in egg yolk relate to parental quality in barn swallows (Hirundo rustica erythrogaster). First, we found no relationship between concentrations or amounts of yolk androgens and carotenoids. Yolk carotenoids decreased with laying order, whereas we found no relationship between yolk androgens and laying order. Second, we tested the Investment Hypothesis, which predicts that high-quality females or females paired to high quality mates, allocate differentially more of these yolk compounds to their offspring. For carotenoids, we mostly found evidence to counter predictions of the Investment hypothesis: (1) Carotenoid concentrations varied among females, (2) heavier eggs contained lower carotenoid concentrations, although heavier yolks contained greater amounts of carotenoids, (3) eggs of earlier-laying females had lower concentrations in their eggs, and (4) yolk carotenoids were not correlated with clutch size or male plumage ornamentation. For androgens, we found weak support for the Investment Hypothesis: (1) Yolk androgens varied among females, (2) heavier eggs and yolks contained greater amounts, although not concentrations of androgens, (3) females paired to more colorful males laid eggs with greater concentrations of androgens, and (4) no effects of laying date or morphological correlates of female quality on androgen concentrations in egg yolks. Overall, these findings suggest that each yolk compound may have different functions and therefore may be regulated by different mechanisms.
AB - Recently, evidence is mounting that females can adaptively engineer the quality of their offspring via the deposition of yolk compounds, including carotenoids and androgens. In this study, we simultaneously consider how both carotenoids and androgens in egg yolk relate to parental quality in barn swallows (Hirundo rustica erythrogaster). First, we found no relationship between concentrations or amounts of yolk androgens and carotenoids. Yolk carotenoids decreased with laying order, whereas we found no relationship between yolk androgens and laying order. Second, we tested the Investment Hypothesis, which predicts that high-quality females or females paired to high quality mates, allocate differentially more of these yolk compounds to their offspring. For carotenoids, we mostly found evidence to counter predictions of the Investment hypothesis: (1) Carotenoid concentrations varied among females, (2) heavier eggs contained lower carotenoid concentrations, although heavier yolks contained greater amounts of carotenoids, (3) eggs of earlier-laying females had lower concentrations in their eggs, and (4) yolk carotenoids were not correlated with clutch size or male plumage ornamentation. For androgens, we found weak support for the Investment Hypothesis: (1) Yolk androgens varied among females, (2) heavier eggs and yolks contained greater amounts, although not concentrations of androgens, (3) females paired to more colorful males laid eggs with greater concentrations of androgens, and (4) no effects of laying date or morphological correlates of female quality on androgen concentrations in egg yolks. Overall, these findings suggest that each yolk compound may have different functions and therefore may be regulated by different mechanisms.
KW - Barn swallow
KW - Hirundo rustica
KW - Investment hypothesis
KW - Maternal effects
KW - Yolk androgens
KW - Yolk carotenoids
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U2 - 10.1007/s00265-007-0470-7
DO - 10.1007/s00265-007-0470-7
M3 - Article
AN - SCOPUS:37349115291
SN - 0340-5443
VL - 62
SP - 427
EP - 438
JO - Behavioral Ecology and Sociobiology
JF - Behavioral Ecology and Sociobiology
IS - 3
ER -