Qiviut cortisol in muskoxen as a potential tool for informing conservation strategies

Abstract

Muskoxen are increasingly exposed to multiple stressors that may impact their health and fitness. We measured stress hormones in their qiviut (wooly undercoat), and found differences across seasons, years and between sexes. Qiviut cortisol is a promising tool for guiding muskox conservation in a rapidly changing Arctic.

Testosterone in ancient hair from an extinct species

“…Hypothetically, measuring glucocorticoid concentrations of a large number of individuals (Di Francesco et al . ), over tens of thousands of years, may link changes in physiological processes with major climatic or other environmental changes, and changes in the mean level of population progesterone over time could suggest trends in reproductive output. Moreover, in keratinized tissues with seasonal growth patterns, such as woolly rhinoceros’ horns, steroid hormones could even be used to examine seasonal changes in the reproductive biology of extinct species.…”

“…The presence of testosterone in a pooled mammoth hair extract was confirmed with LC‐MS/MS using a similar sample preparation method as a recent study of cortisol in muskox qiviut (Di Francesco et al . ). The hair pool was gently washed by water for 3 min, rinsed with HPLC grade isopropyl alcohol, dried by paper towel and placed in a fume hood overnight.…”

“…, ; Koren & Geffen ; Di Francesco et al . ) on Siberian woolly mammoth hair shaft samples that had been previously utilized by Gilbert et al . (, ) for mitogenome sequencing.…”

Of 11 candidate steroids, corticosterone concentration standardized for mass is the most reliable steroid biomarker of nutritional stress across different feather types

“…In mass spectrometry, increasing the number of feathers extracted cannot circumvent this challenge, because background increases with the signal (Berk et al, ). The cold extraction methods used here were specifically chosen to reduce extraction of interfering compounds, yielding improvements in background (Di Francesco et al, ).…”

“…Tubes containing the standards and the feathers were capped and stored in a 4°C fridge for 20 hr, whereas the filter paper samples that were explicitly oils, esters, and waxes were incubated at −20°C for 20 hr. Cold extraction reduces interfering background by reducing the extraction of nonsteroid components of the feather matrix (Di Francesco et al, ). After the sample was gently removed, the extract was evaporated to dryness under N 2 at 40°C in a Techne Sample Concentrator and reconstituted with 150 (back and breast feathers of all birds, and primaries of captive‐reared birds) or 200 (tail feathers of all birds and primaries of wild‐caught birds) µl of H 2 O/MeOH (50/50, v/v).…”