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Breaking down seasonality : Androgen modulation and stress response in a highly stable environment

González-Gómez, Paulina L.; Merrill, Loren; Ellis, Vincenzo A. LU ; Venegas, Cristobal; Pantoja, Javiera I.; Vasquez, Rodrigo A. and Wingfield, John C (2013) In General and Comparative Endocrinology 191. p.1-12
Abstract

Previous studies show that most birds inhabiting temperate regions have well defined life history stages, and they modulate the production of testosterone (T) and corticosterone (CORT) in response to changes in seasonality. In this study we aimed to examine baseline and stress-induced levels of CORT and circulating T in relation with life history stages in the rufous-collared sparrow, Zonotrichia capensis. We carried out this study for a year in a population inhabiting riparian habitats in the Atacama Desert in Chile, one of the most climatically stable and driest places in the world. This environment shows minimal yearly change in average temperature and precipitation is virtually zero. We found individuals breeding, molting and... (More)

Previous studies show that most birds inhabiting temperate regions have well defined life history stages, and they modulate the production of testosterone (T) and corticosterone (CORT) in response to changes in seasonality. In this study we aimed to examine baseline and stress-induced levels of CORT and circulating T in relation with life history stages in the rufous-collared sparrow, Zonotrichia capensis. We carried out this study for a year in a population inhabiting riparian habitats in the Atacama Desert in Chile, one of the most climatically stable and driest places in the world. This environment shows minimal yearly change in average temperature and precipitation is virtually zero. We found individuals breeding, molting and overlapping breeding and molt year round, although most individuals were molting during March and in breeding condition during October. T levels were not related to individual breeding condition, and at population level they were not significantly different across sampling months. Baseline levels of CORT did not vary across the year. Stress-induced levels of CORT were suppressed during March when most of the birds were molting. This phenomenon was also observed in birds not molting during this period suggesting a mechanism other than molt in determining the stress-response suppression. Our results strongly suggest that in this study site, long-term extremely stable conditions could have relaxed the selective pressures over the timing of life history stages which was evidenced by the breeding and molt schedules, its overlap and endocrine profiles.

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Please use this url to cite or link to this publication:
author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Corticosterone, Desert, Endocrine mechanisms, Stable environments, Testosterone, Zonotrichia
in
General and Comparative Endocrinology
volume
191
pages
12 pages
publisher
Elsevier
external identifiers
  • scopus:84879174927
ISSN
0016-6480
DOI
10.1016/j.ygcen.2013.05.007
language
English
LU publication?
no
id
65a5eb70-4468-4096-a40e-4dc5dee9a146
date added to LUP
2017-05-09 17:18:26
date last changed
2018-01-07 12:02:40
@article{65a5eb70-4468-4096-a40e-4dc5dee9a146,
  abstract     = {<p>Previous studies show that most birds inhabiting temperate regions have well defined life history stages, and they modulate the production of testosterone (T) and corticosterone (CORT) in response to changes in seasonality. In this study we aimed to examine baseline and stress-induced levels of CORT and circulating T in relation with life history stages in the rufous-collared sparrow, Zonotrichia capensis. We carried out this study for a year in a population inhabiting riparian habitats in the Atacama Desert in Chile, one of the most climatically stable and driest places in the world. This environment shows minimal yearly change in average temperature and precipitation is virtually zero. We found individuals breeding, molting and overlapping breeding and molt year round, although most individuals were molting during March and in breeding condition during October. T levels were not related to individual breeding condition, and at population level they were not significantly different across sampling months. Baseline levels of CORT did not vary across the year. Stress-induced levels of CORT were suppressed during March when most of the birds were molting. This phenomenon was also observed in birds not molting during this period suggesting a mechanism other than molt in determining the stress-response suppression. Our results strongly suggest that in this study site, long-term extremely stable conditions could have relaxed the selective pressures over the timing of life history stages which was evidenced by the breeding and molt schedules, its overlap and endocrine profiles.</p>},
  author       = {González-Gómez, Paulina L. and Merrill, Loren and Ellis, Vincenzo A. and Venegas, Cristobal and Pantoja, Javiera I. and Vasquez, Rodrigo A. and Wingfield, John C},
  issn         = {0016-6480},
  keyword      = {Corticosterone,Desert,Endocrine mechanisms,Stable environments,Testosterone,Zonotrichia},
  language     = {eng},
  month        = {09},
  pages        = {1--12},
  publisher    = {Elsevier},
  series       = {General and Comparative Endocrinology},
  title        = {Breaking down seasonality : Androgen modulation and stress response in a highly stable environment},
  url          = {http://dx.doi.org/10.1016/j.ygcen.2013.05.007},
  volume       = {191},
  year         = {2013},
}