Data from: Baseline and stress-induced corticosterone levels are heritable and genetically correlated in a barn owl population

The hypothalamic-pituitary-adrenal (HPA) axis is responsible for the
regulation of corticosterone, a hormone that is essential in the mediation
of energy allocation and physiological stress. As a continuous source of
challenge and stress for organisms, the environment has promoted the
evolution of physiological adaptations and led to a great variation in
corticosterone profiles within or among individuals, populations and
species. In order to evolve via natural selection, corticosterone levels
do not only depend on the strength of selection exerted on them but also
on the extent to which the regulation of corticosterone is heritable.
Nevertheless, heritability of corticosterone profiles in wild populations
is still poorly understood. In this study, we estimated the heritability
of baseline and stress-induced corticosterone levels in barn owl (Tyto
alba) nestlings from 8 years of data, using a multivariate animal model
based on a behavioural pedigree. We found that baseline and stress-induced
corticosterone levels are strongly genetically correlated (r = 0.68 –
0.80) and that the heritability of stress-induced corticosterone levels
(h2 = 0.24 – 0.33) was moderate and similar to the heritability of
baseline corticosterone levels (h2 = 0.19 – 0.30). These findings suggest
that the regulation of stress-induced corticosterone and baseline levels
evolve at a similar pace when selection acts with the same intensity on
both traits, and that contrary to previous studies, the evolution of
baseline and stress-induced level is interdependent in barn owls, as they
may be strongly genetically correlated.