Environmental dynamics influence scale cortisol levels in Mexican cavefish

Bauhus, Marc B.; Wander, Luise; Boy, David; Santacruz, Ana; Maldonado, Ernesto; Kurtz, Joachim; Kaiser, Sylvia; Peuß, Robert

Research article in digital collection | Preprint

Abstract

Cortisol is a key hormone involved in stress responses, and its regulation can vary across populations experiencing different environmental pressures. While short term changes in certain environmental factors can result in immediate changes in cortisol levels, it remains unclear whether variable and fluctuating environments affect lifetime stress responses of individuals. In this study, we estimated lifetime-experienced stress in cave- and surface-dwelling populations of Astyanax mexicanus. The advantage of this model is that different populations are confronted with varied dynamics of environmental change, making it an ideal study system to investigate lifetime stress responses upon environmental fluctuations. To estimate lifetime-experienced stress, we measured cortisol levels in the scales of A. mexicanus for the first time using an ELISA assay. We studied six populations from six different habitats (four cave and two surface habitats) that vary in their dynamics of abiotic factors. We analysed scale cortisol levels across two years to examine temporal changes and individual variability within and between populations. Our results show that increased fluctuations in abiotic parameters are associated with an increased cortisol level in scales and, in addition, an increased inter-individual variability within a population irrespective of cave or surface habitat. These findings highlight the influence of varying ecological conditions on lifetime-experienced stress in A. mexicanus, providing insight into potential adaptive mechanisms underlying stress regulation in extreme environments.

Details about the publication

Name of the repositorybioRxiv
StatusPublished
Release year2025 (03/01/2026)
Language in which the publication is writtenEnglish
DOI10.1101/2025.03.09.642216
Link to the full texthttps://www.biorxiv.org/content/10.1101/2025.03.09.642216v1
KeywordsStress; Environment; Scale Cortisol; Astyanax mexicanus

Authors from the University of Münster

Bauhus, Marc
Research Group Animal Evolutionary Ecology (Prof. Kurtz)
Kaiser, Sylvia
Institute for Neuro- and Behavioural Biology (INVB)
Kurtz, Joachim
Research Group Animal Evolutionary Ecology (Prof. Kurtz)
Peuß, Robert
Professur für Tierphysiologie (Prof. Rohner)