Selection on personality in a songbird affects maternal hormone levels tuned to its effect on timing of reproduction.
The increase or decrease in yolk androgens over the laying sequence of a clutch in birds may mitigate or enhance, respectively, the disadvantage of the last-hatched chicks, providing a potentially adaptive tool to adjust brood size to food conditions. This variation may involve a genetic component on which Darwinian selection can act. We found that two lines of a wild bird species selected for bold and shy personalities show, respectively, increased and decreased androgen concentrations over the laying sequence. The line showing the increase laid earlier in the season, when food conditions are normally sufficient to raise the whole brood. The line showing the decrease laid later, when food is normally scarce, which may facilitate brood reduction. The results indicate a correlated response in maternal hormone transfer to genetic selection on personality, which relates to ecological conditions.
Groothuis
Ton G G
TG
Department of Behavioural Biology, University of Groningen, PO Box 14, 9750 AA Haren, The Netherlands. a.g.g.groothuis@rug.nl
Carere
Claudio
C
Lipar
Joe
J
Drent
Piet J
PJ
Schwabl
Hubert
H
D000818:Animals; D003345:Corticosterone / Q000378:metabolism; D004530:Egg Yolk / Q000378:metabolism*; D005260:Female; D012739:Gonadal Steroid Hormones / Q000378:metabolism*; D052287:Oviparity; D010551:Personality; D012641:Selection, Genetic; D020308:Songbirds / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors
D012739:Gonadal Steroid Hormones; D003345:Corticosterone