Baseline corticosterone and stress response in the Thorn-tailed Rayadito (Aphrastura spinicauda) along a latitudinal gradient

Verónica Quirici, Cristóbal I. Venegas, Paulina L. González-Gómez, Gabriel J. Castaño-Villa, John C. Wingfield, Rodrigo A. Vásquez

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)39-46
Number of pages8
JournalGeneral and Comparative Endocrinology
Volume198
DOIs
Publication statusPublished - 1 Mar 2014

Keywords

  • Environmental productivity
  • Furnariidae
  • Geographic range
  • Southern hemisphere

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Endocrinology

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