Big brown bat plasma cortisol (CORT) concentrations by roost type
Description
These data were collected in 2022 and 2023 in northwestern Pennsylvania. The study species is the big brown bat (Eptesicus fuscus; EPFU) with adults and juveniles of both sexes included. The research question for which these data were collected was whether or not roost type affects stress response patterns in EPFU. The hypothesis tested was that circulating cortisol (CORT) levels differ between EPFU maternity colonies inhabiting three different man-made roost types: barns, dwellings, and bat boxes. We predicted that bat boxes may be less optimal roosting sites and that this suboptimal roosting environment would be reflected in both baseline and stress-induced CORT levels significantly differing from those of bats roosting in the other types of sites. There was no significant effect of roost type on CORT concentrations (p = 0.376). However, there was a trend for an interaction effect of roost type and reproductive status. Blood sample order (first vs. second) and mass each significantly affected CORT levels. These results may partially explain why this species has seemingly thrived in human-occupied landscapes. This dataset also increases the known range of adult big brown bat CORT contraptions compared to previously published values and is the first record of baseline CORT concentrations in volant juveniles.
Files
Steps to reproduce
Bats were caught via mist-netting, hand nets, and manual capture. Sample collection occurred at the site of capture. For each bat, the following was recorded/collected within the first three minutes of capture: species, sex, reproductive status, age, and initial blood sample. Blood sampling followed the methods of Smith et al. (2010) using sterile, single-use 29-gauge needles and 100uL heparinized hematocrit capillary tubes. Bats were assigned randomly to one of three treatment groups: Adrenocorticotropic Hormone Challenge (ACTH) group, Sham Control (SC), and Control (C). Bats in the ACTH group were weighed and given a subcutaneous injection of adrenocorticotropic hormone. Bats in the SC group were also weighed prior to receiving a subcutaneous injection of sterile saline. Individuals in the C group were weighed with no injection. After one hour, a second blood sample was collected. As soon as possible following collection, each blood sample was centrifuged; whole blood and plasma were transferred to individual 0.5mL microcentrifuge tubes and frozen. Plasma samples were analyzed in triplicate using enzyme-linked immunosorbent assay (ELISA) multispecies cortisol kits (Cat. #K003-H1W/H5W; Arbor Assays; Ann Arbor, MI, USA) and a xMarkTM microplate absorbance spectrophotometer (Bio-Rad, Hercules, CA, USA) plate reader. All statistical analyses were completed using RStudio (v2023.12.0, Posit Software, PBC). We used a linear mixed-effect model (LMM) to assess the impact of roost type on plasma CORT levels.
Institutions
- College of Saint Benedict and Saint John's UniversityMinnesota, Collegeville
- North Dakota State UniversityNorth Dakota, Fargo