Journal
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
Volume 267, Issue 1451, Pages 1451-1456Publisher
ROYAL SOC
DOI: 10.1098/rspb.2000.1163
Keywords
avian brood reduction; Falco sparverius; hatching asynchrony; maternal androgens; parental favouritism; parent-offspring conflict
Categories
Funding
- NIMH NIH HHS [MH 49877] Funding Source: Medline
Ask authors/readers for more resources
Females may favour some offspring over others by differential deposition of yolk hormones. In American kestrels (Falco sparverius), we found that yolks of eggs laid late in the sequence of a clutch had more testosterone (T) and androstenedione (A(4)) than yolks of first-laid eggs. To investigate the effects of these yolk androgens on nestling 'fitness', we injected both T and A(4) into the yolks of first-laid eggs and compared their hatching time, nestling growth and nestling survival with those of first laid eggs in which we injected vehicle as a control. Compared to controls, injection of T and A, at a dose intended to increase their levels to those of later-laid eggs delayed hatching and reduced nestling growth and survival rates. Yolk androgen treatment of egg 1 had no effect on survival of siblings hatching from subsequently laid eggs. The adverse actions of yolk androgen treatment in the kestrel are in contrast to the favourable actions of yolk T treatment found previously in canaries (Serinus canaria). Additional studies are necessary in order to determine whether the deposition of yolk androgens is an adaptive form of parental favouritism or an adverse by-product of endocrine processes during egg formation. Despite its adaptive significance, such 'transgenerational' effects of steroid hormones may have helped to evolutionarily shape the hormonal mechanisms regulating reproduction.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available