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Fecal Glucocorticoid Analysis: Non-invasive Adrenal Monitoring in Equids
Published on: April 25, 2016
Within seasons and among years: when are corticosterone levels repeatable?
Jenny Q Ouyang1, Michaela Hau, Frances Bonier
1Department of Ecology and Evolutionary Biology, Guyot Hall, Princeton University, Princeton, NJ 08540, USA. jouyang@princeton.edu
Hormones and Behavior
|August 30, 2011
Summary
Hormonal traits, like corticosterone, show limited long-term consistency in wild birds. While baseline levels were repeatable within seasons, plasticity suggests hormones adapt to changing environmental and stress demands.
Area of Science:
- Endocrinology
- Behavioral Ecology
- Evolutionary Biology
Background:
- Hormones integrate environmental cues for life-history, behavior, and physiology.
- Individual consistency of endocrine traits is crucial for understanding selection pressures.
- Glucocorticoids (like corticosterone) manage homeostasis and stress responses.
Purpose of the Study:
- To assess the repeatability of plasma corticosterone concentrations in free-living passerines across multiple years.
- To determine if baseline and stress-induced corticosterone levels are consistent within and among individuals and seasons.
Main Methods:
- Investigated plasma corticosterone concentrations in two species of free-living passerines (great tits and tree swallows).
- Measured repeatability of baseline corticosterone within and across breeding seasons and years.
- Assessed repeatability of stress-induced corticosterone levels in great tits.
Main Results:
- Repeatability of baseline corticosterone was found within breeding seasons for both sexes of great tits and female tree swallows.
- No repeatability of baseline corticosterone was observed across seasons or years.
- Stress-induced corticosterone levels in great tits were not repeatable in either sex.
Conclusions:
- Plasma corticosterone concentrations (both baseline and stress-induced) appear to be plastic traits.
- This plasticity allows individuals to respond to varying long-term and acute demands.
- Individual differences in trait plasticity may influence behavioral and physiological responses to challenges.
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