Balancing between costs and benefits of maternal hormone deposition in avian eggs.
Avian eggs contain substantial amounts of maternal androgens, and several studies have indicated that these are beneficial for the chick. Nevertheless, there is a large and systematic variation in maternal hormone concentrations both within and between clutches. If maternal androgens also involve costs, this might explain why not all mothers put high levels of androgens in their clutches. However, the simultaneous occurrence of both benefits and costs has not yet been convincingly demonstrated. We show experimentally that yolk androgens suppress immune function and simultaneously stimulate growth in black-headed gull chicks. Thus, mothers face a trade-off between these costs and benefits and may tune hormone deposition to prevailing conditions that influence chick survival.
Groothuis
Tong G
TG
Department of Animal Behaviour, University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands. t.groothuis@biol.rug.nl
Eising
Corine M
CM
Dijkstra
Cor
C
Müller
Wendt
W
D000728:Androgens / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D046091:Charadriiformes / Q000196:embryology* / Q000254:growth & development / Q000276:immunology; D004530:Egg Yolk / Q000378:metabolism*; D009425:Nesting Behavior; D013601:T-Lymphocytes / Q000276:immunology
D000728:Androgens