Corticosterone levels predict survival probabilities of Galápagos marine iguanas during El Niño events

Romero, L. Michael; Wikelski, Martin

doi:10.1073/pnas.131091498

Cited by 448 publications

(318 citation statements)

References 32 publications

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“…For example, in the Swainson's thrush (Catharus ustulatus), individuals with naturally high baseline corticosterone levels during the nestling stages showed increased survival rate post-fledging compared to birds showing naturally low basal corticosterone concentrations (Rivers et al 2012). On the other hand, during severe naturally occurring stressful events, such as during the El Niño, corticosterone levels have been observed to increase disproportionately in Galapagos marine iguanas (Amblyrhynchus cristatus) and were negatively correlated with likelihood of survival (Romero & Wikelski 2001). …”

Section: Discussionmentioning

confidence: 99%

Repeated exposure to stressful conditions can have beneficial effects on survival

Marasco

Boner

Heidinger

et al. 2015

Experimental Gerontology

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Repeated exposure to stressful circumstances is generally thought to be associated with increased pathology and reduced longevity. However, growing lines of evidence suggest that the effects of environmental stressors on survival and longevity depend on a multitude of factors and, under some circumstances, might be positive rather than negative. Here, using the zebra finch (Taeniopygia guttata), we show that repeated exposure to stressful conditions (i.e. unpredictable food availability), which induced no changes in body mass, was associated with a decrease in mortality rate and an increase in the age of death. As expected, the treated birds responded to the unpredictable food supply by increasing baseline glucocorticoid stress hormone secretion and there were no signs of habituation of this hormonal response to the treatment across time. Importantly, and consistent with previous literature, the magnitude of hormone increase induced by the treatment was significant, but relatively mild, since the baseline glucocorticoid concentrations in the treated birds were substantially lower than the peak levels that occur during an acute stress response in this species. Taken together, these data demonstrate that protracted exposure to relatively mild stressful circumstances can have beneficial lifespan effects.Key-words. Chronic stress, unpredictable food availability, glucocorticoids, corticosterone, HPA axis, hormesis. IntroductionProtracted or repeated exposure to stressful stimuli, such as those experienced by individuals living in uncontrollable or highly unstable environments, can have wide ranging effects on animal physiology, but the extent to which these effects are adaptive is the subject of considerate debate (Broonstra 2013). In vertebrates, one of the main systems mediating responses to stressful environmental conditions is the Hypothalamic-Pituitary-Adrenal axis (HPA axis), which regulates both basal production and transient surges of circulating glucocorticoid stress hormones. Transient increases in circulating glucocorticoids are a highly conserved component of the vertebrate stress response and play a key role in initiating an array of metabolic changes intended to mobilise energy, including hepatic gluconeogenesis and inhibition of glucose uptake by peripheral tissues . These changes are thought to be vital for promoting short-term survival (Wingfield et al. 1998;Sapolsky 2000). At the same time, dynamic changes in basal level of glucocorticoids, such as those occurring across differing seasons within the same year in a variety of free-living vertebrate species, are also thought to be critical for survival (Romero 2002). Over a longer time scale, however, the repeated activation of the HPA axis may lead to a dysregulation and dysfunction of the stress axis (Sapolsky 2000).The predominant view is that repeated stress exposure, and the consequent prolonged elevation of glucocorticoid levels, is harmful since it can induce a large variety of downstream negative effects, including impairment of brai...

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Section: Discussionmentioning

confidence: 99%

Repeated exposure to stressful conditions can have beneficial effects on survival

Marasco

Boner

Heidinger

et al. 2015

Experimental Gerontology

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“…Baseline corticosterone levels were elevated once body condition dropped below a critical threshold. The rise in corticosterone was hypothesized to be an adaptive response to starvation [84]. Their study shows the selective consequences of variation in physiology affecting survival through El Niñ o events via food availability.…”

Section: Hormones and Potential Responses To Global Changementioning

confidence: 99%

“…Some studies have shown that elevated corticosterone may reduce fitness and survival, i.e. the corticosteronefitness hypothesis [145], through infertility, impaired resistance to disease and inhibition of growth [49,84]. In contrast, other studies suggest that elevated corticosterone promotes adaptive advantages to the individual forming the corticosterone-adaptation hypothesis, [131,146].…”

Section: Hormonal Effects On Components Of Fitnessmentioning

confidence: 99%

Hormonally mediated maternal effects, individual strategy and global change

Meylan¹,

Miles

Clobert

2012

Phil. Trans. R. Soc. B

108

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A challenge to ecologists and evolutionary biologists is predicting organismal responses to the anticipated changes to global ecosystems through climate change. Most evidence suggests that short-term global change may involve increasing occurrences of extreme events, therefore the immediate response of individuals will be determined by physiological capacities and life-history adaptations to cope with extreme environmental conditions. Here, we consider the role of hormones and maternal effects in determining the persistence of species in altered environments. Hormones, specifically steroids, are critical for patterning the behaviour and morphology of parents and their offspring. Hence, steroids have a pervasive influence on multiple aspects of the offspring phenotype over its lifespan. Stress hormones, e.g. glucocorticoids, modulate and perturb phenotypes both early in development and later into adulthood. Females exposed to abiotic stressors during reproduction may alter the phenotypes by manipulation of hormones to the embryos. Thus, hormone-mediated maternal effects, which generate phenotypic plasticity, may be one avenue for coping with global change. Variation in exposure to hormones during development influences both the propensity to disperse, which alters metapopulation dynamics, and population dynamics, by affecting either recruitment to the population or subsequent life-history characteristics of the offspring. We suggest that hormones may be an informative index to the potential for populations to adapt to changing environments.

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“…Our results support the flexible time budget hypothesis, with parents at both Pribilof Islands experiencing relatively poor foraging conditions, but maintaining similar chick-provisioning rates and fledging success by spending more time foraging than Bogoslof birds. However, this flexibility is not without its potential long-term costs, and high levels of CORT (Brown et al, 2005;Kitaysky et al 2007Kitaysky et al , 2010Romero and Wikelski, 2001), and increased parental effort (Golet et al, 1998) may be detrimental to adult survival. Although colony attendance differed among colonies by only 3 min h À 1 , this translates to an extra 48 min in a 16 h day diverted to foraging.…”

Section: Colony Attendancementioning

confidence: 99%

“…Individuals have been shown to respond to a number of stressors such as challenging environmental conditions, parasites, and predators by increasing secretion of CORT (e.g., Raouf et al, 2006;Romero et al, 2000). Levels have also been shown to be elevated during food shortages (Kitaysky et al, 1999a(Kitaysky et al, , 1999b, and in individuals in poor body condition (Kitaysky et al, 1999b;Romero and Wikelski, 2001; but see Schultner et al, 2013). Studies of seabirds have shown that the secretion of CORT is largely driven by changes in food (Benowitz-Fredericks et al, 2008;Kitaysky et al, 1999bKitaysky et al, , 2007Kitaysky et al, , 2010, and a strong negative correlation between CORT and fish abundance has been demonstrated in a number of seabird populations, including common murres (Uria aalge; Kitaysky et al, 2007).…”

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confidence: 99%

Does location really matter? An inter-colony comparison of seabirds breeding at varying distances from productive oceanographic features in the Bering Sea

Harding

Paredes

Suryan

et al. 2013

Deep Sea Research Part II: Topical Studies in Oceanography

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a b s t r a c tCentral place foragers, such as breeding seabirds, need to commute between their nests and foraging grounds, thus close proximity of the breeding colony to productive oceanographic features might be beneficial for seabird reproduction. We tested this hypothesis by investigating the at-sea foraging and breeding behavior of thick-billed murres (Uria lomvia) nesting at three colonies (Bogoslof, St. Paul, and St. George Islands) in the Bering Sea located at different distances from the productive continental shelf-break. We found that distances to feeding areas differed only during night trips among colonies. St. Paul murres foraged entirely on the shelf, whereas St. George murres commuted to the continental shelf-break at night and foraged on the shelf during the day. Bogoslof murres foraged in oceanic waters in close proximity to the colony. Murres breeding at the both Pribilof colonies spent less time attending nests and had higher levels of stress hormone corticosterone compared to murres breeding at Bogoslof, although chick-provisioning rates and fledging success were similar among the three colonies. Lower nest attendance and higher corticosterone suggest lower food availability in the Pribilof domain compared to the Bogoslof region. Murres breeding at the Pribilofs used different foraging strategies to buffer effects of food shortages on their reproduction: flight costs associated with longer distance night trips at St. George were presumably balanced by benefits of higher density and/or more lipid rich prey in the continental shelf-break regions, whereas the additional distance of St. Paul from the continental shelf-break may have outweighed any energetic gain. Murres exhibited a remarkable degree of plasticity of foraging strategies in response to changes in their food availability, but the breeding success of murres did not reflect either food limitations or the colony proximity to productive oceanographic features.

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Corticosterone levels predict survival probabilities of Galápagos marine iguanas during El Niño events

Cited by 448 publications

References 32 publications

Repeated exposure to stressful conditions can have beneficial effects on survival

Repeated exposure to stressful conditions can have beneficial effects on survival

Hormonally mediated maternal effects, individual strategy and global change

Does location really matter? An inter-colony comparison of seabirds breeding at varying distances from productive oceanographic features in the Bering Sea

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