Contrasting fecal corticosterone metabolite levels in captive and free‐living colonial tuco‐tucos (Ctenomys sociabilis)

Abstract

The environment in which an animal lives can profoundly influence its biology, including physiological responses to external stressors. To examine the effects of environmental conditions on physiological stress reactions in colonial tuco-tucos (Ctenomys sociabilis), we measured glucocorticoid (GC) levels in captive and free-living members of this species of social, subterranean rodent. Analyses of plasma and fecal samples revealed immunoreactive corticosterone (metabolites) to be the most prevalent GC in this species. An adrenocorticotropic hormone challenge confirmed that fecal corticosterone metabolites are responsive to exogenous stressors and provided validation of the commercial enzyme immunoassay kit used to detect these metabolites. Comparisons of adult female C. sociabilis from natural and captive environments revealed significantly higher baseline concentrations of corticosterone metabolites and significantly greater individual variation in metabolite concentrations among free-living animals. These findings suggest that the natural environment in which these animals occur is more challenging and more variable than the captive housing conditions employed. In addition to providing the first evaluation of GC levels in captive and wild colonial tuco-tucos, our findings indicate that the influence of environmental conditions on stress physiology may have important implications for understanding the social behavior of this species in the laboratory and the field.

Monitoring physiological stress in semi-free ranging populations of an endangered Australian marsupial, the Greater Bilby (Macrotis lagotis)

“…Based on our findings of difference in mean FCM between the semi-wild and captive populations, we suggest that the wide range of unpredictable environment within the two fenced reserves (SW1 and SW2) sampled for this study are generally more challenging than the predictable stimuli (such as adequate security and environmental enrichment) offered in captivity. Similar results have also been reported in the Tuco-tuco (Ctenoours sociabilis) (Woodruff et al 2010), and yellow-bellied marmot (Marmota flaviventris) (Smith et al 2012). …”

Decreased Fecal Corticosterone Levels Due to Domestication: A Comparison Between the White‐Backed Munia (Lonchura striata) and Its Domesticated Strain, the Bengalese Finch (Lonchura striata var. domestica) With a Suggestion for Complex Song Evolution

“…On the other hand, high CORT levels could be produced in WBMs under captive conditions because of continuous stress from confinement itself or from exposure to humans. Previous results indicated that baseline CORT levels in captive individuals were lower than those in free‐living individuals in some species (Künzl and Sachser, ; Romero and Wingfield, ; Woodruff et al, ). Marra et al () reported that basal CORT levels in captive birds were higher than in free‐living individuals in the white‐throated sparrow ( Zonotrichia albicollis ) and the white‐crowned sparrow ( Zonotrichia leucophrys ).…”

Male convict cichlid 11-ketotestosterone levels throughout the reproductive cycle: an exploratory profile study in laboratory and field populations

“…The majority of behavioral neuroendocrinological experiments on vertebrates have been performed within the laboratory setting, likely due to the obvious advantages of being able to control for variables and the ease of assay-work at the bench top ( Calisi & Bentley, 2009 ). Yet, evidence has shown that stark differences can be seen between laboratory and wild-populations in terms of both their behavior and measured hormone-levels (e.g., Cardwell et al, 1996 ; Woodruff, Lacey & Bentley, 2010 ; Dickens & Bentley, 2014 ; and those reviewed by Calisi & Bentley, 2009 ). In a comparison of wild and captive male cowbirds ( Molothrus ater ), for example, substantial differences were seen in the levels of circulating testosterone.…”