Can synchronizing feather-based measures of corticosterone and stable isotopes help us better understand habitat–physiology relationships?

Abstract

Physiological mechanisms link the environment with population dynamics, and glucocorticoid hormones are of particular interest because they respond adaptively to environmental change and can influence vertebrate reproduction and fitness. We tested a novel approach of synchronizing feather-based measures of corticosterone (the primary avian glucocorticoid; CORTf) and ratios of stable isotopes (SIs) of C (δ(13)C) and N (δ(15)N) to provide information about environmental conditions and an integrated physiological response to those conditions over the same period of feather synthesis. Using a fragmented metapopulation of Dupont's larks Chersophilus duponti, an endangered steppe songbird, we analyzed interrelationships among CORTf, δ(13)C, δ(15)N, and the physical environment, including measures of habitat loss and fragmentation. CORTf was not related to any habitat variable measured directly. However, we detected a significant spatial structure to CORTf values and food availability, with greater similarity in both at smaller spatial scales. Using SIs as proxies for the local environment, we found CORTf was negatively related to δ(13)C. Values of CORTf, δ(13)C, and the relationship between the two were likely driven by variation in agricultural land use surrounding lark habitat patches. Our feather-based approach revealed that individual physiology was sensitive to environmental conditions (e.g., an interaction of food availability and variation in habitat) at a local scale, but not patch or landscape scales. Combining CORTf and SIs may be a promising tool because it can provide individual-based information about habitat, physiology, and their relationship during the same time period.

Ecological relevance of biomarkers in monitoring studies of macro-invertebrates and fish in Mediterranean rivers

“…Nonetheless, immunoassays including white blood cells proliferation and macrophage burst and phagocytic activity can be used either in macro-invertebrates (Galloway and Depledge, 2001) or fish (Zelikoff et al, 2000), and also help disentangle stress from immune responses. The stress-fitness relationship is a pivotal topic in ecology but such relationship is still far from being clear (Fairhurst et al, 2013;Wikelski and Cooke, 2006). Fitness has been positively and negatively related to stress measures in several wild species but as far as we are aware, none of them have focused on wild free-living fish or macroinvertebrates of European Mediterranean rivers.…”

Experimental relationships between levels of corticosterone in plasma and feathers in a free-living bird

“…Work with birds has shown that feathers contain corticosterone (CORT) (Bortolotti et al, 2008;Koren et al, 2012), the primary avian GC. CORT in feathers (CORT f ) has been correlated with variation in parental provisioning (Fairhurst et al, 2012b), nest box microclimate (Fairhurst et al, 2012a), environmental enrichment (Fairhurst et al, 2011), expression of carotenoid-based signals (Bortolotti et al, 2009b;Mougeot et al, 2010;Kennedy et al, 2013), egg mass (Kouwenberg et al, 2013), stable isotopes of carbon (Fairhurst et al, 2013) and components of fitness (Bortolotti et al, 2008;Koren et al, 2012). This biomarker relates to diverse ecological factors, suggesting that it integrates CORT secretion in general, rather than expresses a response to any specific source of environmental variation.…”

Feather corticosterone evaluated by ELISA in broilers: A potential tool to evaluate broiler welfare

“…It has been used as a tool to associate physiology with feather coloration, feather quality, and social signals (Bortolotti et al, 2009b;Lattin et al, 2011;Kennedy et al, 2012;Martínez-Padilla et al, 2013). It has also been applied to assess health condition (Harms et al, 2010;Koren et al, 2012) and to comprehend relationships between habitat and animal physiology (Fairhurst et al, 2011(Fairhurst et al, , 2013, among other applications. Nonetheless, research in the possibilities and potential offered by this matrix is still in its beginnings, with important gaps hindering proper interpretation (Hõrak et al, 2013).…”