Whither the challenge hypothesis?

JC Wingfield, M Ramenofsky, RE Hegner… - Hormones and Behavior, 2020‏ - Elsevier
Almost fifty years ago the advent of assay methods to measure circulating levels of
hormones revolutionized endocrinology in relation to investigations of free-living and captive …

Hormonal, behavioral, and life-history traits exhibit correlated shifts in relation to population establishment in a novel environment

JW Atwell, GC Cardoso, DJ Whittaker… - The American …, 2014‏ - journals.uchicago.edu
Climate change, habitat alteration, range expansions, and biological invasions are all
predicted to require rapid shifts in multiple traits including behavior and life history, both for …

Decoupling pioneering traits from latitudinal patterns in a North American bird experiencing a southward range shift

L Siefferman, AB Bentz… - Journal of Animal Ecology, 2023‏ - Wiley Online Library
Ecogeographic rules describe spatial patterns in biological trait variation and shed light on
the drivers of such variation. In animals, a consensus is emerging that 'pioneering'traits may …

Divergence along the gonadal steroidogenic pathway: implications for hormone-mediated phenotypic evolution

KA Rosvall, CMB Burns, SP Jayaratna… - Hormones and …, 2016‏ - Elsevier
Across a range of taxa, hormones regulate suites of traits that influence survival and
reproductive success; however, the mechanisms by which hormone-mediated traits evolve …

On the existence and potential functions of low-amplitude vocalizations in North American birds

DG Reichard, JF Welklin - The Auk: Ornithological Advances, 2015‏ - academic.oup.com
Research on acoustic communication has focused predominantly on high-amplitude, long-
range vocalizations that are easily recognized from a distance by the human ear. However …

The telomere regulatory gene POT1 responds to stress and predicts performance in nature: Implications for telomeres and life history evolution

SE Wolf, TL Sanders, SE Beltran… - Molecular …, 2022‏ - Wiley Online Library
Telomeres are emerging as correlates of fitness‐related traits and may be important
mediators of ecologically relevant variation in life history strategies. Growing evidence …

[PDF][PDF] Low-amplitude songs produced by male dark-eyed juncos (Junco hyemalis) differ when sung during intra-and inter-sexual interactions

DG Reichard, RJ Rice, EM Schultz… - …, 2013‏ - patricellilab.faculty.ucdavis.edu
The function and relative importance of low-amplitude (quiet) acoustic signals remains a
poorly understood aspect of animal communication. Research in songbirds has …

Gonads and the evolution of hormonal phenotypes

KA Rosvall, CM Bergeon Burns… - Integrative and …, 2016‏ - academic.oup.com
Hormones are dynamic signaling molecules that influence gene activity and phenotype, and
they are thus thought to play a central role in phenotypic evolution. In vertebrates, many …

Baseline and stress-induced levels of corticosterone in male and female Afrotropical and European temperate stonechats during breeding

B Apfelbeck, B Helm, JC Illera, KG Mortega… - BMC Evolutionary …, 2017‏ - Springer
Background Latitudinal variation in avian life histories falls along a slow-fast pace of life
continuum: tropical species produce small clutches, but have a high survival probability …

Hypothalamic–pituitary–adrenal axis activity is not elevated in a songbird (Junco hyemalis) preparing for migration

CM Bauer, KB Needham, CN Le, EC Stewart… - General and …, 2016‏ - Elsevier
During spring, increasing daylengths stimulate gonadal development in migratory birds.
However, late-stage reproductive development is typically postponed until migration has …