TY - JOUR
T1 - Baseline corticosterone and stress response in the Thorn-tailed Rayadito (Aphrastura spinicauda) along a latitudinal gradient
AU - Quirici, Verónica
AU - Venegas, Cristóbal I.
AU - González-Gómez, Paulina L.
AU - Castaño-Villa, Gabriel J.
AU - Wingfield, John C.
AU - Vásquez, Rodrigo A.
N1 - Funding Information:
We warmly thank Juan Monardez, María Olga Bargsted, Nasrim Butler, Victor L. Gutiérrez and Cristian Celis for help with fieldwork, and Daniel Naya for statistical advice and help with data analysis. Two anonymous reviewers provided useful comments to improve a previous version of this manuscript. Funding was provided by FONDECYT Grant (No. 1100359 ) to V.Q., and Grants from FONDECYT (No. 1090794 ), ICM-005-002, and PFB-23-CONICYT to R.A.V. Essay work was supported by a USA National Science Foundation Grant (No. IOS-0750540 ) to J.C.W. Research was conducted under permit Nos. 5193 and 6295 issued by the Servicio Agrícola y Ganadero (SAG), Chile, with the supervision of the Ethics Committee of the Faculty of Sciences, Universidad de Chile. We thank Corporación Nacional Forestal (CONAF) for allowing our fieldwork at Fray Jorge National Park.
PY - 2014/3/1
Y1 - 2014/3/1
N2 - Glucocorticoids are essential for life and their secretion is regulated by the hypothalamic-pituitary-adrenal axis (HPA). The HPA axis is often divided into two components: baseline glucocorticoids levels and stress response glucocorticoids levels, which are affected by changes in ambient temperature and productivity among others factors. An approximation to evaluate how a species copes with these changes is to evaluate differences of this hormone amongst populations of the same species that inhabit places ideally presenting all the possible combinations of temperature and productivity. We aimed to evaluate whether environmental temperature or productivity, represent challenges in terms of stress in the Thorn-tailed Rayadito (Aphrastura spinicauda). We examined circulating baseline levels of CORT and stress responses from three populations, covering the whole geographic distribution of the species across large gradients in weather conditions. If low temperature influences baseline CORT levels, we expect higher levels of this hormone in the southernmost population (higher latitude). However, if productivity is the factor that influences baseline CORT levels, we expect the contrary pattern, that is, lower values of this hormone in the southernmost population (more productive environment). We observed that baseline CORT levels presented lower values in the southernmost population, supporting the environmental productivity hypothesis. Secondly, we tested the hypothesis that individuals breeding at higher latitudes should have a lower stress response than individuals breeding at lower latitudes. Contrary to our expectations, we found that stress response did not vary among populations in any of the three years. We concluded that low environmental temperatures did not represent a stress situation for the Thorn-tailed Rayadito if food abundance was sufficient to support energetic demands.
AB - Glucocorticoids are essential for life and their secretion is regulated by the hypothalamic-pituitary-adrenal axis (HPA). The HPA axis is often divided into two components: baseline glucocorticoids levels and stress response glucocorticoids levels, which are affected by changes in ambient temperature and productivity among others factors. An approximation to evaluate how a species copes with these changes is to evaluate differences of this hormone amongst populations of the same species that inhabit places ideally presenting all the possible combinations of temperature and productivity. We aimed to evaluate whether environmental temperature or productivity, represent challenges in terms of stress in the Thorn-tailed Rayadito (Aphrastura spinicauda). We examined circulating baseline levels of CORT and stress responses from three populations, covering the whole geographic distribution of the species across large gradients in weather conditions. If low temperature influences baseline CORT levels, we expect higher levels of this hormone in the southernmost population (higher latitude). However, if productivity is the factor that influences baseline CORT levels, we expect the contrary pattern, that is, lower values of this hormone in the southernmost population (more productive environment). We observed that baseline CORT levels presented lower values in the southernmost population, supporting the environmental productivity hypothesis. Secondly, we tested the hypothesis that individuals breeding at higher latitudes should have a lower stress response than individuals breeding at lower latitudes. Contrary to our expectations, we found that stress response did not vary among populations in any of the three years. We concluded that low environmental temperatures did not represent a stress situation for the Thorn-tailed Rayadito if food abundance was sufficient to support energetic demands.
KW - Environmental productivity
KW - Furnariidae
KW - Geographic range
KW - Southern hemisphere
UR - http://www.scopus.com/inward/record.url?scp=84892475225&partnerID=8YFLogxK
U2 - 10.1016/j.ygcen.2013.12.010
DO - 10.1016/j.ygcen.2013.12.010
M3 - Article
C2 - 24384532
AN - SCOPUS:84892475225
SN - 0016-6480
VL - 198
SP - 39
EP - 46
JO - General and Comparative Endocrinology
JF - General and Comparative Endocrinology
ER -