No island-effect on glucocorticoid levels for a rodent from a near-shore archipelago

Abstract

Island rodents are often larger and live at higher population densities than their mainland counterparts, characteristics that have been referred to as ''island syndrome''. Island syndrome has been well studied, but few studies have tested for island-mainland differences in stress physiology. We evaluated island syndrome within the context of stress physiology of white-footed mice (Peromyscus leucopus) captured from 11 islands and five mainland sites in Thousand Islands National Park, Ontario, Canada. Stress physiology was evaluated by quantifying corticosterone (a stress biomarker), the primary glucocorticoid in mice, from hair and its related metabolites from fecal samples. White-footed mice captured in this near-shore archipelago did not display characteristics of island syndrome, nor differences in levels of hair corticosterone or fecal corticosterone metabolites compared with mainland mice. We suggest that island white-footed mice experience similar degrees of stress in the Thousand Islands compared with the mainland. Although we did not find evidence of island syndrome or differences in glucocorticoid levels, we identified relationships between internal (sex, body mass) and external (season) factors and our hormonal indices of stress in whitefooted mice. . ArensA, McNab BK. 2001. The comparative energetics of caviomorph rodents. Comparative Biochemistry and Physiology Part A 130:105-122. Barrett K, Anderson WB, Wait DA, Grismer LL, Polis GA, Rose MD. 2005. Marine subsidies alter the diet and abundance of insular and coastal lizard populations. Dewsbury DA, Baumgardner DJ, Evans RL, Webster DG. 1980. Sexual dimorphism for body mass in 13 taxa of muroid rodents under laboratory conditions. Journal of Mammalogy 61:146-149 DOI 10.2307/1379975. Erickson RL, Browne CA, Lucki I. 2017. Hair corticsterone measurement in mouse models of type 1 and type 2 diabetes mellitus. Physiology and Behavior 178:166-171 hormone research in uncontrolled, natural environments: the problem with sex, diet, metabolic rate and the individual: non-invasive hormone research. Methods in Ecology and Evolution 3:757-765 Harper GA, Rutherford M. 2016. Home range and population density of black rats (Rattus rattus) on a seabird island: a case for a marine subsidised effect? New Zealand Journal of Ecology 40:219-228. Harper JM, Austad SN. 2000. Fecal glucocorticoids: a noninvasive method of measuring adrenal activity in wild and captive rodents. Physiological and Biochemical Zoology: Ecological and Evolutionary Approaches 73:12-22 DOI 10.1086/316721. Harper JM, Austad SN. 2001. Effect of capture and season on fecal glucocorticoid levels in deer mice (peromyscus maniculatus) and red-backed voles (clethrionomys gapperi). General and Comparative Endocrinology 123:337-344 DOI 10.1006/gcen.2001.7682. Hayssen V, Harper JM, DeFina R. 2002. Fecal corticosteroids in agouti and non-agouti deer mice (Peromyscus maniculatus). Comparative Biochemistry and Physiology Part . Holding ML, Frazier JA, Dorr SW, Pollock NB, Muelleman PJ, Branske A, Henningsen SN...

Physical Injuries and Hair Corticosterone Concentration in Rabbit Kits from Single- and Group-Housed Does Kept on a Commercial Farm

“…It is possible that the GC response of males and females depends on the type of stressor and the age of the rabbits. Considering other species where the hair GC concentration was measured, in polar bears [17,45] and black bears [46], as well as in non-human primates [47], an influence of sex was found, but not in wild house mice [48], wild white-footed mice [49], rats [50], and in grizzly bears [51]. However, it must be taken into account that the animals in all these studies were already sexually mature, which could also be an explanation for why there was no difference between male and female kits in our study.…”

Seasonal Hair Glucocorticoid Fluctuations in Wild Mice (Phyllotis darwini) within a Semi-Arid Landscape in North-Central Chile

“…To measure HCC, we followed the protocols outlined by Mastromonaco et al (2014) [52] and Stewart et al (2020) [53]. Initially, two to three weeks after sampling, samples were subjected to a washing step to remove potential surface contaminants.…”