TY - JOUR
T1 - Endocrine correlates of dominance in chicks of the blue-footed booby (sula nebouxii)
T2 - Testing the challenge hypothesis
AU - Ramos-Fernández, G.
AU - Núñez-de la Mora, A.
AU - Drummond, H.
AU - Wingfield, J. C.
N1 - Funding Information:
We thank the Mexican Navy for logistical support and the fishermen of Nayarit for help of all kinds. We thank Lynn Erckmann and Steve Schoech for help in the hormone analyses, and Carlos Valverde-R. for helpful comments on the manuscript. Financial support was provided by the Universidad Nacional Aut6noma de Mexico (DGAPA-UNAM IN211491), the National Geographic Society to H. Drummond (4535-91), and DCB9005081 and IBN9408013 from the National Science Foundation to J. Wingfield. The Secretaria de Desarrollo Urbano y Ecologia granted permissions to work on Isla Isabel.
PY - 2000/3/1
Y1 - 2000/3/1
N2 - Two-chick broods of the blue-footed booby develop a dominance relationship during the junior chick’s first 2 weeks of life, when behaviour of the subordinate chick is conditioned through aggression by its 4-day-older sibling. We used natural and experimental situations to test the Challenge Hypothesis, which predicts a rise in testosterone to regulate aggression only in socially unstable situations, and to investigate the role of corticosterone in the development of submissive behaviour in subordinates. In unmanipulated broods during the first 12 days, we found no differences among singletons, dominants and subordinates in testosterone levels, and corticosterone levels did not differ significantly. In experimental pairings of singleton/dominant and singleton/subordinate, testosterone was not detected and corticosterone increased significantly in dominants and singletons, but not in subordinates. These results indicate that the Challenge Hypothesis does not apply to these young birds. Whether or not circulating corticosterone regulates aggression in chicks awaits further experimentation.
AB - Two-chick broods of the blue-footed booby develop a dominance relationship during the junior chick’s first 2 weeks of life, when behaviour of the subordinate chick is conditioned through aggression by its 4-day-older sibling. We used natural and experimental situations to test the Challenge Hypothesis, which predicts a rise in testosterone to regulate aggression only in socially unstable situations, and to investigate the role of corticosterone in the development of submissive behaviour in subordinates. In unmanipulated broods during the first 12 days, we found no differences among singletons, dominants and subordinates in testosterone levels, and corticosterone levels did not differ significantly. In experimental pairings of singleton/dominant and singleton/subordinate, testosterone was not detected and corticosterone increased significantly in dominants and singletons, but not in subordinates. These results indicate that the Challenge Hypothesis does not apply to these young birds. Whether or not circulating corticosterone regulates aggression in chicks awaits further experimentation.
KW - Aggression
KW - Birds
KW - Challenge Hypothesis
KW - Corticosterone
KW - Dominance
KW - Hormones
KW - Testosterone
UR - http://www.scopus.com/inward/record.url?scp=0034162283&partnerID=8YFLogxK
U2 - 10.1080/03949370.2000.9728441
DO - 10.1080/03949370.2000.9728441
M3 - Artículo
SN - 0394-9370
VL - 12
SP - 27
EP - 34
JO - Ethology Ecology and Evolution
JF - Ethology Ecology and Evolution
IS - 1
ER -