Sex differences in yolk hormones depend on maternal social status in Leghorn chickens (Gallus gallus domesticus)

Wendt Mueller, Corine M. Eising, Cornelis Dijkstra, Ton G.G. Groothuis

Research output: Contribution to journalArticleAcademicpeer-review

123 Citations (Scopus)
334 Downloads (Pure)

Abstract

Maternal hormones are known to be present in avian eggs and can have beneficial effects on chick development. Recently, differences in avian yolk steroid concentrations between the sexes have been demonstrated, and in this context steroids have been proposed to be part of the avian sex-determining mechanism. In our study, we show that it is very unlikely that androgen concentrations alone are the decisive part of the sex-determining mechanism. We found that sex-specific differences in the yolk hormones strongly depend on the social rank of the mother. First, dominant females, but not subdominant females, allocated significantly more testosterone to male eggs than to female eggs. Second, subordinate females increased the testosterone concentrations of female eggs.

This pattern of yolk hormone deposition can be functionally explained. In polygynous species such as the chicken, reproductive success is more variable in males than in females. Parental investment in sons or daughters is therefore expected to occur in direct relation to parental rearing capacities. We found that the social status of a hen was indeed negatively correlated with her maternal capacities (for example, body mass, egg mass). Differential androgen deposition might thus provide a mechanism for adaptive maternal investment depending on both the sex of the egg and the social status of the mother.

Original languageEnglish
Pages (from-to)2249-2255
Number of pages7
JournalProceedings of the Royal Society of London. Series B, Biological Sciences
Volume269
Issue number1506
DOIs
Publication statusPublished - 7-Nov-2002

Keywords

  • maternal effects
  • yolk androgens
  • social dominance
  • sex ratio
  • domestic chicken
  • TESTOSTERONE LEVELS
  • ZEBRA FINCH
  • EGGS
  • ANDROGENS
  • DOMINANCE
  • BIRDS
  • ATTRACTIVENESS
  • INVESTMENT
  • MECHANISM
  • SELECTION

Cite this