Knowledge Tree
emergency life history stage
Also known as: ELHS, physiological state level C
Facts (62)
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Allostasis revisited: A perception, variation, and risk framework frontiersin.org Sep 28, 2022 60 facts
referenceWhen an animal relies on cues indicating a threat to Potential Reproductive Potential (PRP) and responds with anticipatory elevation in glucocorticoid levels, it can lead to Emergency Life History Stage (ELHS) activation and/or homeostatic overload as described in the Reactive Scope model.
claimHomeostatic overload is most analogous to Type 2 allostatic overload, where prolonged high hormone levels are damaging but an Emergency Life History Stage (ELHS) is not triggered.
claimAllostatic overload Type 2 occurs when allostatic load is chronically high but the animal is not in a negative energy balance, and in this state, an emergency life-history stage (ELHS) is not triggered.
claimGlucocorticoid concentrations rise from level A (homeostatic level) to level B (reactive scope) as conditions deteriorate, and to level C (allostatic overload) when conditions become extreme, which triggers facultative responses such as the Emergency Life History Stage (ELHS).
claimThe effects of the emergency life-history stage (ELHS) at 'physiological state level C' are mediated primarily through the low-affinity glucocorticoid receptor.
claimAllostatic overload Type I, glucocorticoid excess, and Emergency Life History Stage (ELHS) activation occur when an animal's integrated perception yields a perceived Perceived Resource Potential (PRP) of less than or equal to 0.
claimStrategy 1 for Emergency Life History Stage (ELHS) activation involves glucocorticoids gradually elevating in inverse correlation with Potential Resource Availability (PRP) when PRP is low, reaching the threshold for ELHS activation only when PRP equals zero.
referenceError management theory suggests that the choice to respond or not to an expected cue provides information about the relative historical costs of different response errors in ELHS (Emergency Life History Stage) activation.
claimELHS activation, referred to as 'physiological state level C,' occurs when glucocorticoid concentrations are consistently elevated above the seasonal norm for the life-history stage, known as 'physiological state level B'.
claimAllostatic overload triggers an 'emergency life-history stage' (ELHS), which redirects an individual's physiology and behavior toward survival.
claimIndirect life-history factors (LPFs) do not constitute a direct threat to energy balance because they are typically brief, such as predation attempts, social challenges, or sudden extreme weather events, but they may elicit a glucocorticoid response that contributes to ELHS activation.
claimAnimals may favor the risk of a false negative error by relying on prolonged energy imbalance to trigger the emergency life-history stage (ELHS).
claimIf Emergency Life History Stage (ELHS) activation does not cause damage because it is short-lived, it falls within the range of reactive homeostasis and is considered a normal, adaptive response to an abnormal perturbation.
referenceHomeostatic overload is analogous to the 'level C' regulatory range described in Landys et al. (2006) and is most similar to Type 2 allostatic overload, where prolonged high hormone levels are damaging but an Emergency Life History Stage (ELHS) is not triggered.
claimThe decision to elevate glucocorticoid levels to engage the Emergency Life-History Stage (ELHS) resembles the decision prey animals make regarding flight-initiation-distance in response to a perceived predation threat.
claimIn birds, repeated acute stressors induce symptoms of chronic stress, suggesting that such events could cumulatively lead to Emergency Life History Stage (ELHS) activation.
claimIn Strategy 1 of endocrine response, glucocorticoids gradually elevate in inverse correlation with Potential Resource Predictability (PRP), reaching the Emergency Life History Stage (ELHS) activation threshold only when PRP equals zero.
claimThe Emergency Life History Stage (ELHS) is defined as a functional threshold where glucocorticoid elevation drives physiology.
claimAnimals may interpret stimuli previously classified as 'stressors' as cues to estimate the probability and severity of threats to their Perturbation Resistance Potential (PRP) when managing errors in decisions to engage the Emergency Life-History Stage (ELHS).
claimThe Emergency Life-History Stage (ELHS) is a conserved suite of physiological and behavioral responses driven by glucocorticoid action, characterized by the cessation of normal life-history stages and reproductive inhibition.
claimBoth allostasis and reactive scope models designate a point at which 'overload' results from elevated mediator levels, leading to the activation of the Emergency Life History Stage (ELHS) and/or physiological damage.
claimWord et al. (2022) highlight that glucocorticoid action has common but contradictory effects on locomotor activity, serving as a key example of how the Emergency Life-History Stage (ELHS) activation can have variable impacts.
claimError management theory can be applied to understand glucocorticoid responsiveness and the activation of the Emergency Life History Stage (ELHS).
claimAccording to error management theory, the direction of bias in an animal's response decision provides information about the relative historical costs of different response errors during Emergency Life History Stage (ELHS) activation.
claimGlucocorticoid suppression during Phase II starvation suggests a non-linear increase in glucocorticoids, which may be consistent with a strategy where glucocorticoids increase exponentially near the point where the potential reproductive period (PRP) is less than or equal to zero and the Emergency Life History Stage (ELHS) activation threshold is surpassed.
claimThe threshold at which the Emergency Life History Stage (ELHS) is activated is not clearly defined by receptor occupancy.
referenceLabile perturbation factors (LPFs) occur over varying time frames and are classified as either direct, necessitating a shift to the Emergency Life History Stage (ELHS), or indirect, where they may be disruptive and costly but do not initiate overload, according to Wingfield (2005) and Romero and Wingfield (2016).
claimWhen the consequences of false positive errors are sufficiently dire, selection may favor an increase in tolerance for false negative responses to reduce the probability of incorrectly activating the Emergency Life History Stage (ELHS) and inhibiting reproduction.
referenceSapolsky et al. (2000) and Vera et al. (2017) suggest that future research should address the preparative actions of glucocorticoids in the expression of the Emergency Life History Stage (ELHS) when environmental conditions worsen.
perspectiveWingfield et al. (2011) assert that Emergency Life History Stage (ELHS) activation is unfavorable or unlikely in environments with either extremely high or extremely low predictability over evolutionary time.
claimThe cost of activating the Emergency Life History Stage (ELHS) includes surrendering fitness-related investments associated with a normal life-history stage and potentially increasing the risk of damage associated with Type II/allostatic overload.
claimModeling the activation of the Emergency Life History Stage (ELHS) requires utilizing studies that address how animals use environmental information to make survival-related decisions.
claimThe activation of the Emergency Life History Stage (ELHS) is functionally comparable to a behavioral decision.
claimStrategy 2 for endocrine response involves an animal maintaining glucocorticoid levels near a seasonal baseline until PRP is critically low, at which point only a negative energy balance results in a rise in glucocorticoid levels that trigger the ELHS.
claimThe emergency life history stage (ELHS) is triggered when perturbation resistance potential is reduced near the zero point due to environmental perturbations, extreme weather, perceived predation risk, or fear, allowing coping mechanisms while suppressing normal life history stages.
claimAcute perturbations are known to influence subsequent physiological responsiveness and may cumulatively contribute toward the activation of the ELHS (Emergency Life History Stage).
claimThe framework of error management theory can be applied to glucocorticoid responsiveness leading to the activation of the Emergency Life-History Stage (ELHS).
claimIn Strategy 2 of endocrine response, an animal maintains glucocorticoid levels near a seasonal baseline until Potential Resource Predictability (PRP) is critically low, at which point only a negative energy balance triggers the Emergency Life History Stage (ELHS).
claimThe principles of error management theory regarding bias in decision-making can be applied to understanding glucocorticoid responsiveness and the activation of the Emergency Life History Stage (ELHS).
claimThe Emergency Life History Stage (ELHS) is induced by elevated secretion of glucocorticoid hormones.
claimThe elevation of glucocorticoids toward the threshold of Emergency Life History Stage (ELHS) activation is functionally similar to behavioral decisions made by animals.
claimThe impacts of Emergency Life-History Stage (ELHS) activation are influenced by behavioral and flexible consequences of glucocorticoid stimulation following neural integration and the endocrine decision to secrete glucocorticoids.
claimElevated glucocorticoid levels indicate a perception of perturbation and systemic activation of the Emergency Life History Stage (ELHS). These levels are more reliable as an indicator in less-responsive individuals favoring Type 2 error, though Type 1 error in hormone response is propagated to the outcome.
claimIn highly predictable environments, animals may not respond to many cues but are expected to initiate an Emergency Life History Stage (ELHS) in response to irrefutable cues like prolonged negative energy balance.
claimAn organism engaging in decision-making about activating the Emergency Life-History Stage (ELHS) must navigate the risks of remaining in its normal seasonal life-history stage to face an energetic crisis unprepared versus reducing the duration over which such a crisis can be survived.
claimNeural integration can influence behavioral outcomes and alter target tissue sensitivity via physiological pathways, potentially reshaping the physiology of the Emergency Life-History Stage (ELHS).
claimThe emergency life-history stage (ELHS) is a physiological state triggered by allostatic overload that redirects physiology and behavior toward individual survival, often interrupting normal life history stages.
claimActivation of the 'emergency life-history stage' (ELHS), referred to as 'physiological state level C', occurs when glucocorticoid concentrations are consistently elevated above the seasonal norm for the life-history stage, which is referred to as 'physiological state level B'.
claimThe emergency life-history stage (ELHS) is induced by the elevated secretion of glucocorticoid hormones.
claimElevated glucocorticoid levels indicate a perception of perturbation and systemic activation of the Emergency Life History Stage (ELHS).
claimIn the context of the emergency life-history stage (ELHS), stimuli traditionally labeled as 'stressors' can be reclassified as cues that animals use to assess the probability and severity of threats to their perturbation resistance potential (PRP).
claimStrategy 1 for endocrine response involves glucocorticoids gradually elevating in direct inverse correlation with the difference between allostatic load and resource availability (PRP) when PRP is low, reaching the ELHS activation threshold only when PRP equals zero.
claimBusch et al. (2008a,b) suggest that acute perturbations may cumulatively contribute toward the activation of the Emergency Life History Stage (ELHS).
claimType 1 allostatic overload may lead to homeostatic overload, but this is not always the case; if Emergency Life History Stage (ELHS) activation is short-lived and does not cause damage, it falls within the range of reactive homeostasis.
claimElevated glucocorticoid levels increase the probability that additional perturbations will lead to Emergency Life History Stage (ELHS) activation.
claimBaseline glucocorticoid levels in blood tend to increase slowly as environmental conditions deteriorate, increasing allostatic load, until conditions become extreme, at which point glucocorticoid levels increase rapidly to level C, triggering facultative responses such as the Emergency Life History Stage (ELHS).
claimThe conserved nature of the Emergency Life-History Stage (ELHS) response allows for variable associations with diverse behavioral outcomes.
claimStrategy 2 for Emergency Life History Stage (ELHS) activation involves an animal maintaining glucocorticoid levels near a seasonal baseline until Potential Resource Availability (PRP) is critically low, at which point negative energy balance triggers a rise in glucocorticoids and ELHS activation.
claimThe 'emergency life-history stage' (ELHS) often interrupts normal life history stages, with the extent of the interruption depending on the intensity and duration of the perturbation and individual trade-off decisions.
claimWhen environmental conditions become extreme, glucocorticoid levels increase rapidly to level C as a result of allostatic overload, which triggers facultative responses such as the Emergency Life History Stage (ELHS).
Stress and Animal Health: Physiological Mechanisms and ... - Nature nature.com 1 fact
referenceJohn C. Wingfield et al. authored the paper 'Ecological bases of hormone-behavior interactions: The "emergency life history stage"', published in American Zoologist in 1998, which explores the concept of an emergency life history stage in the context of hormone-behavior interactions.
Understanding Allostasis: Stability Through Change - Cannelevate cannelevate.com.au Jan 2, 2026 1 fact
claimType 1 allostatic overload activates an 'emergency life history stage' characterized by a shift to survival mode, escape responses, and decreased thyroid hormone (T3) levels to conserve energy; it can resolve once the perturbation passes and resources become available.